false--12-31 Q3 2020 0000352541 0000052485 0000107832 381232 374246 26.24 28.28 1000000 1000000 0.355 1.065 0.38 1.14 0.01 2.50 5.00 0.01 2.50 5.00 480000000 24000000 18000000 480000000 24000000 18000000 13370788 13236601 13370788 13236601 0000352541 2020-01-01 2020-09-30 0000352541 lnt:WplMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember 2020-09-30 0000352541 2020-09-30 0000352541 lnt:WplMember 2020-09-30 0000352541 2019-07-01 2019-09-30 0000352541 2020-07-01 2020-09-30 0000352541 2019-01-01 2019-09-30 0000352541 2019-12-31 0000352541 2019-09-30 0000352541 2018-12-31 0000352541 lnt:IplMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember 2019-12-31 0000352541 lnt:IplMember 2018-12-31 0000352541 lnt:IplMember 2019-09-30 0000352541 lnt:WplMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember 2019-12-31 0000352541 lnt:WplMember 2018-12-31 0000352541 lnt:WplMember 2019-09-30 0000352541 us-gaap:AccountingStandardsUpdate201613Member 2019-12-31 0000352541 lnt:ElectricTransmissionCostRecoveryMember 2020-09-30 0000352541 lnt:WplMember lnt:ElectricTransmissionCostRecoveryMember 2020-09-30 0000352541 lnt:WplMember us-gaap:RemovalCostsMember 2019-12-31 0000352541 lnt:WplMember us-gaap:RemovalCostsMember 2020-09-30 0000352541 lnt:IplMember us-gaap:DeferredDerivativeGainLossMember 2020-09-30 0000352541 us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2020-09-30 0000352541 lnt:WplMember lnt:ElectricTransmissionCostRecoveryMember 2019-12-31 0000352541 lnt:ElectricTransmissionCostRecoveryMember 2019-12-31 0000352541 lnt:IplMember lnt:ElectricTransmissionCostRecoveryMember 2019-12-31 0000352541 lnt:WplEarningsSharingMechanismMember 2020-09-30 0000352541 lnt:TaxRelatedMember 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2019-12-31 0000352541 us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2019-12-31 0000352541 lnt:WplMember lnt:CommodityCostRecoveryMember 2020-09-30 0000352541 lnt:WestRiversideLiquidatedDamagesMember 2020-09-30 0000352541 lnt:IplMember lnt:TaxRelatedMember 2020-09-30 0000352541 us-gaap:DeferredDerivativeGainLossMember 2020-09-30 0000352541 lnt:CommodityCostRecoveryMember 2019-12-31 0000352541 lnt:WplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2020-09-30 0000352541 lnt:WplMember lnt:TaxRelatedMember 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2019-12-31 0000352541 lnt:WplMember lnt:TaxRelatedMember 2019-12-31 0000352541 lnt:IplMember lnt:CommodityCostRecoveryMember 2020-09-30 0000352541 us-gaap:RemovalCostsMember 2019-12-31 0000352541 lnt:IplMember us-gaap:DeferredDerivativeGainLossMember 2019-12-31 0000352541 lnt:IplMember lnt:TaxRelatedMember 2019-12-31 0000352541 us-gaap:RemovalCostsMember 2020-09-30 0000352541 us-gaap:DeferredDerivativeGainLossMember 2019-12-31 0000352541 lnt:WplMember lnt:CommodityCostRecoveryMember 2019-12-31 0000352541 lnt:WplMember lnt:WplEarningsSharingMechanismMember 2020-09-30 0000352541 lnt:WplEarningsSharingMechanismMember 2019-12-31 0000352541 lnt:IplMember us-gaap:RemovalCostsMember 2020-09-30 0000352541 lnt:WplMember us-gaap:DeferredDerivativeGainLossMember 2020-09-30 0000352541 lnt:TaxRelatedMember 2019-12-31 0000352541 lnt:CommodityCostRecoveryMember 2020-09-30 0000352541 lnt:IplMember us-gaap:RemovalCostsMember 2019-12-31 0000352541 lnt:WplMember lnt:WestRiversideLiquidatedDamagesMember 2020-09-30 0000352541 lnt:WplMember lnt:WplEarningsSharingMechanismMember 2019-12-31 0000352541 lnt:WplMember us-gaap:DeferredDerivativeGainLossMember 2019-12-31 0000352541 lnt:IplMember lnt:ElectricTransmissionCostRecoveryMember 2020-09-30 0000352541 lnt:WestRiversideLiquidatedDamagesMember 2019-12-31 0000352541 lnt:IplMember lnt:CommodityCostRecoveryMember 2019-12-31 0000352541 lnt:IplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2020-09-30 0000352541 us-gaap:DeferredDerivativeGainLossMember 2019-12-31 0000352541 lnt:IplMember lnt:AssetsRetiredEarlyMember 2019-12-31 0000352541 lnt:EmissionAllowancesMember 2019-12-31 0000352541 lnt:WplMember us-gaap:AssetRetirementObligationCostsMember 2020-09-30 0000352541 lnt:DAECPPAMember 2020-09-30 0000352541 lnt:IplMember us-gaap:AssetRetirementObligationCostsMember 2020-09-30 0000352541 lnt:WplMember lnt:AssetsRetiredEarlyMember 2019-12-31 0000352541 us-gaap:AssetRetirementObligationCostsMember 2020-09-30 0000352541 us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2019-12-31 0000352541 lnt:IplMember us-gaap:DeferredDerivativeGainLossMember 2019-12-31 0000352541 lnt:IplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2019-12-31 0000352541 lnt:WplMember us-gaap:DeferredDerivativeGainLossMember 2020-09-30 0000352541 us-gaap:PensionAndOtherPostretirementPlansCostsMember 2019-12-31 0000352541 lnt:IplMember us-gaap:DeferredIncomeTaxChargesMember 2019-12-31 0000352541 lnt:AssetsRetiredEarlyMember 2020-09-30 0000352541 us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2020-09-30 0000352541 lnt:WplMember us-gaap:DeferredIncomeTaxChargesMember 2020-09-30 0000352541 us-gaap:AssetRetirementObligationCostsMember 2019-12-31 0000352541 lnt:WplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2020-09-30 0000352541 lnt:IplMember us-gaap:PensionAndOtherPostretirementPlansCostsMember 2019-12-31 0000352541 lnt:IplMember lnt:DAECPPAMember 2019-12-31 0000352541 lnt:WplMember us-gaap:PensionAndOtherPostretirementPlansCostsMember 2019-12-31 0000352541 lnt:DAECPPAMember 2019-12-31 0000352541 lnt:IplMember lnt:AssetsRetiredEarlyMember 2020-09-30 0000352541 lnt:IplMember lnt:EmissionAllowancesMember 2020-09-30 0000352541 lnt:IplMember us-gaap:DeferredDerivativeGainLossMember 2020-09-30 0000352541 lnt:IplMember us-gaap:PensionAndOtherPostretirementPlansCostsMember 2020-09-30 0000352541 lnt:AssetsRetiredEarlyMember 2019-12-31 0000352541 lnt:WplMember us-gaap:PensionAndOtherPostretirementPlansCostsMember 2020-09-30 0000352541 lnt:WplMember us-gaap:AssetRetirementObligationCostsMember 2019-12-31 0000352541 us-gaap:DeferredIncomeTaxChargesMember 2020-09-30 0000352541 lnt:IplMember lnt:EmissionAllowancesMember 2019-12-31 0000352541 us-gaap:DeferredIncomeTaxChargesMember 2019-12-31 0000352541 lnt:EmissionAllowancesMember 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherRegulatoryAssetsLiabilitiesMember 2019-12-31 0000352541 lnt:WplMember us-gaap:DeferredDerivativeGainLossMember 2019-12-31 0000352541 us-gaap:DeferredDerivativeGainLossMember 2020-09-30 0000352541 us-gaap:PensionAndOtherPostretirementPlansCostsMember 2020-09-30 0000352541 lnt:WplMember us-gaap:DeferredIncomeTaxChargesMember 2019-12-31 0000352541 lnt:IplMember us-gaap:DeferredIncomeTaxChargesMember 2020-09-30 0000352541 lnt:WplMember lnt:AssetsRetiredEarlyMember 2020-09-30 0000352541 lnt:IplMember us-gaap:AssetRetirementObligationCostsMember 2019-12-31 0000352541 lnt:IplMember lnt:DAECPPAMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CatastropheMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CatastropheMember 2020-08-01 2020-08-31 0000352541 lnt:DAECPPAMember 2020-09-01 2020-09-30 0000352541 lnt:IplMember lnt:ElectricTransmissionCostRecoveryMember 2020-04-01 2020-06-30 0000352541 lnt:IplMember srt:ScenarioForecastMember us-gaap:CatastropheMember 2020-12-31 0000352541 us-gaap:CatastropheMember 2020-09-30 0000352541 lnt:IplMember us-gaap:FinanceReceivablesMember 2020-09-30 0000352541 lnt:IplMember us-gaap:FinanceReceivablesMember 2019-12-31 0000352541 lnt:IplMember srt:MaximumMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember srt:WeightedAverageMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember srt:WeightedAverageMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember srt:MaximumMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember srt:WeightedAverageMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember srt:MaximumMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember srt:WeightedAverageMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember srt:MaximumMember 2020-01-01 2020-09-30 0000352541 lnt:InvestmentInAtcMember 2020-07-01 2020-09-30 0000352541 lnt:InvestmentInAtcMember 2020-01-01 2020-09-30 0000352541 lnt:NonutilityWindInvestmentInOklahomaMember 2020-01-01 2020-09-30 0000352541 lnt:InvestmentInAtcMember 2019-07-01 2019-09-30 0000352541 lnt:OtherEquityMethodInvestmentsMember 2019-01-01 2019-09-30 0000352541 lnt:OtherEquityMethodInvestmentsMember 2020-01-01 2020-09-30 0000352541 lnt:NonutilityWindInvestmentInOklahomaMember 2019-07-01 2019-09-30 0000352541 lnt:OtherEquityMethodInvestmentsMember 2019-07-01 2019-09-30 0000352541 lnt:InvestmentInAtcMember 2019-01-01 2019-09-30 0000352541 lnt:OtherEquityMethodInvestmentsMember 2020-07-01 2020-09-30 0000352541 lnt:NonutilityWindInvestmentInOklahomaMember 2020-07-01 2020-09-30 0000352541 lnt:NonutilityWindInvestmentInOklahomaMember 2019-01-01 2019-09-30 0000352541 us-gaap:RetainedEarningsMember 2020-01-01 2020-09-30 0000352541 us-gaap:RetainedEarningsMember 2019-09-30 0000352541 us-gaap:PreferredStockMember 2018-12-31 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2018-12-31 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-12-31 0000352541 us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-09-30 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-09-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2020-01-01 2020-09-30 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2018-12-31 0000352541 us-gaap:RetainedEarningsMember 2018-12-31 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2020-01-01 2020-09-30 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-01-01 2019-09-30 0000352541 us-gaap:CommonStockMember 2019-12-31 0000352541 us-gaap:RetainedEarningsMember 2019-12-31 0000352541 us-gaap:AccountingStandardsUpdate201613Member us-gaap:RetainedEarningsMember 2020-01-01 2020-09-30 0000352541 us-gaap:PreferredStockMember 2019-12-31 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2019-12-31 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2019-09-30 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2020-01-01 2020-09-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000352541 us-gaap:CommonStockMember 2018-12-31 0000352541 us-gaap:CommonStockMember 2020-09-30 0000352541 us-gaap:PreferredStockMember 2020-09-30 0000352541 us-gaap:RetainedEarningsMember 2019-01-01 2019-09-30 0000352541 us-gaap:CommonStockMember 2019-09-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2020-09-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2019-12-31 0000352541 us-gaap:RetainedEarningsMember 2020-09-30 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2020-09-30 0000352541 us-gaap:PreferredStockMember 2019-09-30 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2020-09-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2019-09-30 0000352541 lnt:WplMember us-gaap:CommonStockMember 2018-12-31 0000352541 lnt:WplMember us-gaap:CommonStockMember 2019-12-31 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2020-09-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2019-12-31 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2020-09-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2019-12-31 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:CommonStockMember 2020-09-30 0000352541 lnt:WplMember us-gaap:CommonStockMember 2019-09-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2018-12-31 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2019-09-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2019-09-30 0000352541 lnt:IplMember us-gaap:PreferredStockMember 2020-09-30 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2020-06-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2019-09-30 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:PreferredStockMember 2019-09-30 0000352541 lnt:IplMember us-gaap:CommonStockMember 2020-06-30 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2019-06-30 0000352541 lnt:IplMember us-gaap:PreferredStockMember 2019-06-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2020-06-30 0000352541 lnt:IplMember us-gaap:CommonStockMember 2020-09-30 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2019-09-30 0000352541 lnt:IplMember us-gaap:PreferredStockMember 2020-06-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2019-06-30 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2020-09-30 0000352541 lnt:IplMember 2019-06-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember 2020-06-30 0000352541 lnt:IplMember us-gaap:CommonStockMember 2019-06-30 0000352541 lnt:IplMember us-gaap:CommonStockMember 2019-09-30 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2020-09-30 0000352541 us-gaap:RetainedEarningsMember 2020-07-01 2020-09-30 0000352541 us-gaap:RetainedEarningsMember 2019-07-01 2019-09-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2019-07-01 2019-09-30 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2020-06-30 0000352541 2020-06-30 0000352541 us-gaap:PreferredStockMember 2019-06-30 0000352541 us-gaap:RetainedEarningsMember 2019-06-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2020-07-01 2020-09-30 0000352541 us-gaap:CommonStockMember 2020-06-30 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2019-07-01 2019-09-30 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2020-06-30 0000352541 us-gaap:CommonStockMember 2019-06-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2019-06-30 0000352541 2019-06-30 0000352541 us-gaap:PreferredStockMember 2020-06-30 0000352541 us-gaap:AccumulatedOtherComprehensiveIncomeMember 2019-06-30 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2020-07-01 2020-09-30 0000352541 us-gaap:DeferredCompensationShareBasedPaymentsMember 2019-06-30 0000352541 us-gaap:RetainedEarningsMember 2020-06-30 0000352541 us-gaap:AdditionalPaidInCapitalMember 2020-06-30 0000352541 lnt:IplMember us-gaap:PreferredStockMember 2019-12-31 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2019-12-31 0000352541 lnt:IplMember us-gaap:PreferredStockMember 2018-12-31 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:CommonStockMember 2019-12-31 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2018-12-31 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2018-12-31 0000352541 lnt:IplMember us-gaap:RetainedEarningsMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2019-12-31 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:AdditionalPaidInCapitalMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:CommonStockMember 2018-12-31 0000352541 lnt:WplMember us-gaap:CommonStockMember 2020-06-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2019-06-30 0000352541 lnt:WplMember 2020-06-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2019-06-30 0000352541 lnt:WplMember us-gaap:CommonStockMember 2019-06-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember 2019-06-30 0000352541 lnt:WplMember us-gaap:RetainedEarningsMember 2020-06-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember us-gaap:AdditionalPaidInCapitalMember 2020-06-30 0000352541 us-gaap:ForwardContractsMember 2020-01-01 2020-09-30 0000352541 us-gaap:ForwardContractsMember 2020-01-01 2020-03-31 0000352541 us-gaap:ForwardContractsMember 2020-03-31 0000352541 us-gaap:ForwardContractsMember 2019-11-01 2019-11-30 0000352541 us-gaap:ForwardContractsMember 2019-11-30 0000352541 lnt:AlliantEnergyFinanceLLCMember lnt:TermLoanCreditAgreementThroughMarchTwoThousandTwentyTwoMember lnt:TermLoanCreditAgreementMember 2020-09-30 0000352541 lnt:AlliantEnergyFinanceLLCMember lnt:TermLoanCreditAgreementThroughAprilTwoThousandandTwentyMember lnt:TermLoanCreditAgreementMember 2020-03-01 2020-03-31 0000352541 lnt:WplMember lnt:FourPointSixPercentDebentureDueTwoThousandTwentyMember lnt:DebenturesMember 2020-06-30 0000352541 lnt:WplMember lnt:ThreePointSixFivePercentDebenturesDueTwoThousandFiftyMember lnt:DebenturesMember 2020-09-30 0000352541 lnt:IplMember lnt:TwoPointThreePercentSeniorDebenturesDueTwoThousandThirtyMember lnt:SeniorDebenturesMember 2020-06-01 2020-06-30 0000352541 lnt:IplMember lnt:ThreePointSixFivePercentSeniorDebenturesDueTwoThousandTwentyMember lnt:SeniorDebenturesMember 2020-06-01 2020-06-30 0000352541 lnt:WplMember lnt:ThreePointSixFivePercentDebenturesDueTwoThousandFiftyMember lnt:DebenturesMember 2020-04-01 2020-04-30 0000352541 lnt:AlliantEnergyFinanceLLCMember lnt:TermLoanCreditAgreementThroughMarchTwoThousandTwentyTwoMember lnt:TermLoanCreditAgreementMember 2020-03-01 2020-03-31 0000352541 lnt:IplMember lnt:TwoPointThreePercentSeniorDebenturesDueTwoThousandThirtyMember lnt:SeniorDebenturesMember 2020-09-30 0000352541 lnt:WplMember lnt:FourPointSixPercentDebentureDueTwoThousandTwentyMember lnt:DebenturesMember 2020-06-01 2020-06-30 0000352541 lnt:IplMember lnt:ThreePointSixFivePercentSeniorDebenturesDueTwoThousandTwentyMember lnt:SeniorDebenturesMember 2020-06-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:SteamMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:RetailIndustrialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 us-gaap:AllOtherSegmentsMember 2019-07-01 2019-09-30 0000352541 lnt:SteamMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:RetailResidentialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:WholesaleMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:WholesaleMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:RetailIndustrialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 us-gaap:AllOtherSegmentsMember 2020-07-01 2020-09-30 0000352541 us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:SteamMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:TransportationandOtherMember us-gaap:AllOtherSegmentsMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:RetailIndustrialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:RetailCommercialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:RetailResidentialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 us-gaap:OtherCustomerMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:RetailIndustrialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:WholesaleMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:WholesaleMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:RetailCommercialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:WholesaleMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:RetailResidentialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:WholesaleMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:RetailCommercialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:RetailCommercialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:TransportationandOtherMember us-gaap:AllOtherSegmentsMember 2020-07-01 2020-09-30 0000352541 lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:GasMember 2019-07-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:ElectricMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:RetailResidentialMember lnt:GasMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:ElectricMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:SteamMember lnt:OtherUtilityMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:RetailCommercialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailCommercialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:SteamMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:SteamMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:WholesaleMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailResidentialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:RetailIndustrialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailCommercialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 us-gaap:OtherCustomerMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailResidentialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 us-gaap:OtherCustomerMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:TransportationandOtherMember us-gaap:AllOtherSegmentsMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailIndustrialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:RetailCommercialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 us-gaap:AllOtherSegmentsMember 2020-01-01 2020-09-30 0000352541 lnt:WholesaleMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailResidentialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 us-gaap:AllOtherSegmentsMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:WholesaleMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:WholesaleMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:RetailIndustrialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:RetailCommercialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:TransportationandOtherMember us-gaap:AllOtherSegmentsMember 2019-01-01 2019-09-30 0000352541 lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:WholesaleMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailIndustrialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:RetailIndustrialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailIndustrialMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:RetailResidentialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:WholesaleMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailCommercialMember lnt:ElectricMember 2019-01-01 2019-09-30 0000352541 lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:RetailResidentialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:ElectricMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:RetailResidentialMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 us-gaap:OtherCustomerMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherCustomerMember lnt:GasMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:SteamMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherCustomerMember lnt:GasMember 2020-01-01 2020-09-30 0000352541 lnt:SteamMember lnt:OtherUtilityMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:DomesticCountryMember 2020-09-30 0000352541 us-gaap:DomesticCountryMember 2020-09-30 0000352541 lnt:WplMember us-gaap:StateAndLocalJurisdictionMember 2020-09-30 0000352541 lnt:WplMember us-gaap:DomesticCountryMember 2020-09-30 0000352541 us-gaap:StateAndLocalJurisdictionMember 2020-09-30 0000352541 lnt:IplMember us-gaap:StateAndLocalJurisdictionMember 2020-09-30 0000352541 lnt:WplMember us-gaap:PensionPlansDefinedBenefitMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember us-gaap:PensionPlansDefinedBenefitMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember us-gaap:PensionPlansDefinedBenefitMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-09-30 0000352541 us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-09-30 0000352541 us-gaap:PensionPlansDefinedBenefitMember 2020-07-01 2020-09-30 0000352541 us-gaap:PensionPlansDefinedBenefitMember 2020-01-01 2020-09-30 0000352541 us-gaap:PensionPlansDefinedBenefitMember 2019-07-01 2019-09-30 0000352541 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2020-07-01 2020-09-30 0000352541 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-07-01 2019-09-30 0000352541 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-09-30 0000352541 us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2020-01-01 2020-09-30 0000352541 us-gaap:RestrictedStockUnitsRSUMember 2020-01-01 2020-09-30 0000352541 lnt:PerformanceRestrictedStockUnitMember 2020-01-01 2020-09-30 0000352541 us-gaap:PerformanceSharesMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:PensionPlansDefinedBenefitMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:PensionPlansDefinedBenefitMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:PensionPlansDefinedBenefitMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember us-gaap:OtherPostretirementBenefitPlansDefinedBenefitMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:PensionPlansDefinedBenefitMember 2019-01-01 2019-09-30 0000352541 lnt:OmnibusIncentivePlanMember 2020-01-01 2020-09-30 0000352541 srt:MinimumMember 2020-01-01 2020-09-30 0000352541 srt:MaximumMember 2020-01-01 2020-09-30 0000352541 lnt:FtrsMwhsMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember srt:NaturalGasPerThousandCubicFeetMember us-gaap:CommodityMember 2020-09-30 0000352541 lnt:WplMember srt:FuelMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember srt:NaturalGasPerThousandCubicFeetMember us-gaap:CommodityMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CoalContractMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:CoalContractMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:FtrsMwhsMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember srt:FuelMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 us-gaap:CoalContractMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 srt:FuelMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 srt:NaturalGasPerThousandCubicFeetMember us-gaap:CommodityMember 2020-09-30 0000352541 lnt:IplMember lnt:FtrsMwhsMember us-gaap:CommodityMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:CommodityContractMember 2019-12-31 0000352541 us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:WplMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2019-12-31 0000352541 us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2019-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2020-06-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2020-06-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2019-06-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2019-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2019-06-30 0000352541 lnt:IplMember us-gaap:FairValueInputsLevel2Member 2020-09-30 0000352541 lnt:IplMember us-gaap:FairValueInputsLevel3Member 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-09-30 0000352541 lnt:IplMember us-gaap:FairValueInputsLevel1Member 2019-12-31 0000352541 lnt:IplMember us-gaap:FairValueInputsLevel2Member 2019-12-31 0000352541 lnt:IplMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member 2019-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member 2020-09-30 0000352541 lnt:IplMember us-gaap:FairValueInputsLevel1Member 2020-09-30 0000352541 lnt:IplMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000352541 lnt:IplMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member 2019-12-31 0000352541 us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2019-01-01 2019-09-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2020-01-01 2020-09-30 0000352541 us-gaap:CommodityContractMember 2020-01-01 2020-09-30 0000352541 us-gaap:CommodityContractMember 2019-01-01 2019-09-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2019-09-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2018-12-31 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2019-12-31 0000352541 us-gaap:CommodityContractMember 2019-09-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2020-09-30 0000352541 us-gaap:CommodityContractMember 2018-12-31 0000352541 us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:WplMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000352541 lnt:WplMember us-gaap:FairValueInputsLevel2Member 2020-09-30 0000352541 lnt:WplMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-09-30 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member 2019-12-31 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member 2019-12-31 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member 2020-09-30 0000352541 lnt:WplMember us-gaap:FairValueInputsLevel2Member 2019-12-31 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-09-30 0000352541 lnt:WplMember us-gaap:FairValueInputsLevel1Member 2020-09-30 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member 2020-09-30 0000352541 lnt:WplMember us-gaap:FairValueInputsLevel3Member 2020-09-30 0000352541 lnt:WplMember us-gaap:FairValueInputsLevel1Member 2019-12-31 0000352541 lnt:WplMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member 2020-09-30 0000352541 lnt:WplMember us-gaap:CommodityContractMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000352541 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member 2020-09-30 0000352541 us-gaap:FairValueInputsLevel1Member 2020-09-30 0000352541 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member 2020-09-30 0000352541 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel2Member 2019-12-31 0000352541 us-gaap:FairValueInputsLevel3Member 2020-09-30 0000352541 us-gaap:FairValueInputsLevel2Member 2019-12-31 0000352541 us-gaap:FairValueInputsLevel2Member 2020-09-30 0000352541 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member 2019-12-31 0000352541 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-09-30 0000352541 us-gaap:CommodityContractMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000352541 us-gaap:FairValueInputsLevel3Member 2019-12-31 0000352541 us-gaap:CarryingReportedAmountFairValueDisclosureMember 2019-12-31 0000352541 us-gaap:CommodityContractMember us-gaap:CarryingReportedAmountFairValueDisclosureMember 2020-09-30 0000352541 us-gaap:FairValueInputsLevel1Member 2019-12-31 0000352541 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel3Member 2019-12-31 0000352541 us-gaap:CommodityContractMember us-gaap:FairValueInputsLevel1Member 2020-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2019-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2018-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:DeferredProceedsOfReceivablesSoldMember 2018-12-31 0000352541 lnt:IplMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2020-07-01 2020-09-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2019-07-01 2019-09-30 0000352541 us-gaap:CommodityContractMember 2019-06-30 0000352541 us-gaap:CommodityContractMember 2019-07-01 2019-09-30 0000352541 us-gaap:CommodityContractMember 2020-07-01 2020-09-30 0000352541 us-gaap:CommodityContractMember 2020-06-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2019-06-30 0000352541 lnt:DeferredProceedsOfReceivablesSoldMember 2020-06-30 0000352541 lnt:WplMember lnt:ExcludingFinancialTransmissionRightsMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:ExcludingFinancialTransmissionRightsMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember lnt:ExcludingFinancialTransmissionRightsMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:ExcludingFinancialTransmissionRightsMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:WplMember lnt:ExcludingFinancialTransmissionRightsMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:WplMember lnt:FinancialTransmissionRightsMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:WplMember lnt:FinancialTransmissionRightsMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember lnt:ExcludingFinancialTransmissionRightsMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:IplMember lnt:FinancialTransmissionRightsMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:FinancialTransmissionRightsMember us-gaap:CommodityContractMember 2020-09-30 0000352541 lnt:FinancialTransmissionRightsMember us-gaap:CommodityContractMember 2019-12-31 0000352541 lnt:IplMember lnt:FinancialTransmissionRightsMember us-gaap:CommodityContractMember 2020-09-30 0000352541 us-gaap:NaturalGasProcessingPlantMember 2020-09-30 0000352541 lnt:IplMember us-gaap:NaturalGasProcessingPlantMember 2020-09-30 0000352541 lnt:IplMember srt:MaximumMember us-gaap:NaturalGasProcessingPlantMember 2020-01-01 2020-09-30 0000352541 srt:MinimumMember us-gaap:NaturalGasProcessingPlantMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember srt:MinimumMember us-gaap:NaturalGasProcessingPlantMember 2020-01-01 2020-09-30 0000352541 srt:MaximumMember us-gaap:NaturalGasProcessingPlantMember 2020-01-01 2020-09-30 0000352541 lnt:WhitingPetroleumCorporationMember 2020-07-01 2020-09-30 0000352541 lnt:WhitingPetroleumCorporationMember 2020-01-01 2020-09-30 0000352541 us-gaap:IndemnificationGuaranteeMember lnt:PurchasedPowerMember 2020-09-30 0000352541 lnt:IplMember lnt:FederalEnergyRegulatoryCommissionMember 2020-01-01 2020-09-30 0000352541 lnt:FederalEnergyRegulatoryCommissionMember 2020-05-01 2020-05-31 0000352541 lnt:IplMember us-gaap:IndemnificationGuaranteeMember 2020-09-30 0000352541 us-gaap:IndemnificationGuaranteeMember 2020-09-30 0000352541 lnt:WhitingPetroleumCorporationMember 2020-03-31 0000352541 lnt:WplMember lnt:CapitalPurchaseObligationMember 2020-01-01 2020-09-30 0000352541 lnt:FederalEnergyRegulatoryCommissionMember 2019-01-01 2019-12-31 0000352541 lnt:WhitingPetroleumCorporationMember 2020-09-30 0000352541 lnt:WplMember lnt:FederalEnergyRegulatoryCommissionMember 2020-01-01 2020-09-30 0000352541 lnt:CapitalPurchaseObligationMember 2020-01-01 2020-09-30 0000352541 lnt:WhitingPetroleumCorporationMember us-gaap:AccountingStandardsUpdate201613Member 2019-12-31 0000352541 lnt:WplMember us-gaap:PublicUtilitiesInventoryNaturalGasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:CoalSupplyAgreementsMember 2020-01-01 2020-09-30 0000352541 us-gaap:PublicUtilitiesInventoryNaturalGasMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:LongTermPurchaseCommitmentsOtherMember 2020-01-01 2020-09-30 0000352541 lnt:LongTermPurchaseCommitmentsOtherMember 2020-01-01 2020-09-30 0000352541 us-gaap:CoalSupplyAgreementsMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:LongTermPurchaseCommitmentsOtherMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember us-gaap:CoalSupplyAgreementsMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember us-gaap:PublicUtilitiesInventoryNaturalGasMember 2020-01-01 2020-09-30 0000352541 us-gaap:UnregulatedOperationMember us-gaap:AllOtherSegmentsMember 2019-01-01 2019-09-30 0000352541 lnt:UtilityBusinessMember 2020-01-01 2020-09-30 0000352541 us-gaap:UnregulatedOperationMember us-gaap:AllOtherSegmentsMember 2020-01-01 2020-09-30 0000352541 lnt:UtilityBusinessMember 2019-01-01 2019-09-30 0000352541 us-gaap:UnregulatedOperationMember us-gaap:AllOtherSegmentsMember 2020-07-01 2020-09-30 0000352541 lnt:UtilityBusinessMember 2020-07-01 2020-09-30 0000352541 lnt:UtilityBusinessMember 2019-07-01 2019-09-30 0000352541 us-gaap:UnregulatedOperationMember us-gaap:AllOtherSegmentsMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember us-gaap:SubsidiaryOfCommonParentMember 2019-12-31 0000352541 lnt:WplMember lnt:CorporateServicesMember us-gaap:SubsidiaryOfCommonParentMember 2020-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember us-gaap:SubsidiaryOfCommonParentMember 2019-12-31 0000352541 lnt:IplMember lnt:CorporateServicesMember us-gaap:SubsidiaryOfCommonParentMember 2020-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2020-07-01 2020-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2020-01-01 2020-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2020-07-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2019-07-01 2019-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionSalesCreditedMember us-gaap:SubsidiaryOfCommonParentMember 2019-07-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2020-01-01 2020-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2019-01-01 2019-09-30 0000352541 lnt:WplMember lnt:CorporateServicesMember lnt:TransmissionPurchasesBilledMember us-gaap:SubsidiaryOfCommonParentMember 2019-01-01 2019-09-30 0000352541 lnt:IplMember lnt:CorporateServicesMember lnt:AdministrativeandGeneralServicesBillingsMember us-gaap:SubsidiaryOfCommonParentMember 2020-01-01 2020-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:WplOwedAtcMember us-gaap:EquityMethodInvesteeMember 2020-09-30 0000352541 lnt:WplMember lnt:AmericanTransmissionCompanyLlcAtcMember us-gaap:EquityMethodInvesteeMember 2020-04-01 2020-06-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:WplOwedAtcMember us-gaap:EquityMethodInvesteeMember 2019-12-31 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:AtcBillingsToWplMember us-gaap:EquityMethodInvesteeMember 2019-01-01 2019-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:WplBillingsToAtcMember us-gaap:EquityMethodInvesteeMember 2019-07-01 2019-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:WplBillingsToAtcMember us-gaap:EquityMethodInvesteeMember 2020-01-01 2020-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:WplBillingsToAtcMember us-gaap:EquityMethodInvesteeMember 2020-07-01 2020-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:AtcBillingsToWplMember us-gaap:EquityMethodInvesteeMember 2020-01-01 2020-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:AtcBillingsToWplMember us-gaap:EquityMethodInvesteeMember 2019-07-01 2019-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:AtcBillingsToWplMember us-gaap:EquityMethodInvesteeMember 2020-07-01 2020-09-30 0000352541 lnt:AmericanTransmissionCompanyLlcAtcMember lnt:WplBillingsToAtcMember us-gaap:EquityMethodInvesteeMember 2019-01-01 2019-09-30 xbrli:shares iso4217:USD xbrli:shares xbrli:pure iso4217:USD lnt:customer lnt:Dekatherms utreg:T utreg:gal utreg:MWh
Table of Contents
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 10-Q

☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the quarterly period ended September 30, 2020
or
☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
For the transition period from to
Name of Registrant, State of Incorporation, Address of Principal Executive Offices, Telephone Number, Commission File Number, IRS Employer Identification Number
ALLIANT ENERGY CORP ORATION
(a Wisconsin Corporation)
4902 N. Biltmore Lane
Madison, Wisconsin 53718
Telephone (608) 458-3311
Commission File Number - 1-9894
IRS Employer Identification Number - 39-1380265
INTERSTATE POWER & LIGHT CO MPANY
(an Iowa corporation)
Alliant Energy Tower
Cedar Rapids, Iowa 52401
Telephone (319) 786-4411
Commission File Number - 1-4117
IRS Employer Identification Number - 42-0331370
WISCONSIN POWER & LIGHT CO MPANY
(a Wisconsin corporation)
4902 N. Biltmore Lane
Madison, Wisconsin 53718
Telephone (608) 458-3311
Commission File Number - 0-337
IRS Employer Identification Number - 39-0714890
This combined Form 10-Q is separately filed by Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company. Information contained in the Form 10-Q relating to Interstate Power and Light Company and Wisconsin Power and Light Company is filed by each such registrant on its own behalf. Each of Interstate Power and Light Company and Wisconsin Power and Light Company makes no representation as to information relating to registrants other than itself.
Securities registered pursuant to Section 12(b) of the Act:
Alliant Energy Corporation, Common Stock, $0.01 Par Value, Trading Symbol LNT, Nasdaq Global Select Market
Interstate Power and Light Company, 5.100% Series D Cumulative Perpetual Preferred Stock, $0.01 Par Value, Trading Symbol IPLDP, Nasdaq Global Select Market
Indicate by check mark whether the registrants (1) have filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrants were required to file such reports), and (2) have been subject to such filing requirements for the past 90 days.
Alliant Energy Corporation - Yes ☒ No ☐
Interstate Power and Light Company - Yes ☒ No ☐
Wisconsin Power and Light Company - Yes ☒ No ☐
Indicate by check mark whether the registrants have submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrants were required to submit such files).
Alliant Energy Corporation - Yes ☒ No ☐
Interstate Power and Light Company - Yes ☒ No ☐
Wisconsin Power and Light Company - Yes ☒ No ☐
Indicate by check mark whether the registrants are large accelerated filers, accelerated filers, non-accelerated filers, smaller reporting companies, or emerging growth companies. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.
Alliant Energy Corporation - Large Accelerated Filer ☒ Accelerated Filer ☐ Non-accelerated Filer ☐ Smaller Reporting Company ☐ Emerging Growth Company ☐
Interstate Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐
Wisconsin Power and Light Company - Large Accelerated Filer ☐ Accelerated Filer ☐ Non-accelerated Filer ☒ Smaller Reporting Company ☐ Emerging Growth Company ☐
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.
Alliant Energy Corporation ☐
Interstate Power and Light Company ☐
Wisconsin Power and Light Company ☐
Indicate by check mark whether the registrants are shell companies (as defined in Rule 12b-2 of the Exchange Act).
Alliant Energy Corporation - Yes ☐ No ☒
Interstate Power and Light Company - Yes ☐ No ☒
Wisconsin Power and Light Company - Yes ☐ No ☒
Number of shares outstanding of each class of common stock as of September 30, 2020:
Alliant Energy Corporation, Common Stock, $0.01 par value, 249,760,663 shares outstanding
Interstate Power and Light Company, Common Stock, $2.50 par value, 13,370,788 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)
Wisconsin Power and Light Company, Common Stock, $5 par value, 13,236,601 shares outstanding (all outstanding shares are owned beneficially and of record by Alliant Energy Corporation)

Table of Contents
TABLE OF CONTENTS

| Page
Definitions | 1
Forward-looking Statements | 1
Part I. Financial Information | 3
Item 1. Condensed Consolidated Financial Statements (Unaudited) | 3
Alliant Energy Corporation | 3
Interstate Power and Light Company | 6
Wisconsin Power and Light Company | 9
Combined Notes to Condensed Consolidated Financial Statements | 12
1. Summary of Significant Accounting Policies | 12
2. Regulatory Matters | 13
3. Receivables | 14
4. Investments | 14
5. Common Equity | 15
6. Debt | 17
7. Revenues | 18
8. Income Taxes | 19
9. Benefit Plans | 19
10. Asset Retirement Obligations | 20
11. Derivative Instruments | 20
12. Fair Value Measurements | 21
13. Commitments and Contingencies | 23
14. Segments of Business | 25
15. Related Parties | 26
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of Operations | 27
Item 3. Quantitative and Qualitative Disclosures About Market Risk | 36
Item 4. Controls and Procedures | 37
Part II. Other Information | 37
Item 1A. Risk Factors | 37
Item 2. Unregistered Sales of Equity Securities and Use of Proceeds | 38
Item 6. Exhibits | 38
Signatures | 39

Table of Contents
DEFINITIONS
The following abbreviations or acronyms used in this report are defined below:

Abbreviation or Acronym | Definition | Abbreviation or Acronym | Definition
2019 Form 10-K | Combined Annual Report on Form 10-K filed by Alliant Energy, IPL and WPL for the year ended Dec. 31, 2019 | GAAP | U.S. generally accepted accounting principles
AEF | Alliant Energy Finance, LLC | IPL | Interstate Power and Light Company
Alliant Energy | Alliant Energy Corporation | IUB | Iowa Utilities Board
ATC | American Transmission Company LLC | MDA | Management’s Discussion and Analysis of Financial Condition and Results of Operations
ATC Holdings | Interest in American Transmission Company LLC and ATC Holdco LLC | MISO | Midcontinent Independent System Operator, Inc.
Corporate Services | Alliant Energy Corporate Services, Inc. | MW | Megawatt
COVID-19 | Novel coronavirus | MWh | Megawatt-hour
DAEC | Duane Arnold Energy Center | N/A | Not applicable
Dth | Dekatherm | Note(s) | Combined Notes to Condensed Consolidated Financial Statements
EGU | Electric generating unit | OPEB | Other postretirement benefits
EPA | U.S. Environmental Protection Agency | PPA | Purchased power agreement
EPS | Earnings per weighted average common share | PSCW | Public Service Commission of Wisconsin
Federal Tax Reform | Tax Cuts and Jobs Act | U.S. | United States of America
FERC | Federal Energy Regulatory Commission | West Riverside | West Riverside Energy Center
Financial Statements | Condensed Consolidated Financial Statements | Whiting Petroleum | Whiting Petroleum Corporation
FTR | Financial transmission right | WPL | Wisconsin Power and Light Company

FORWARD-LOOKING STATEMENTS
Statements contained in this report that are not of historical fact are forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995. These forward-looking statements can be identified as such because the statements include words such as “may,” “believe,” “expect,” “anticipate,” “plan,” “project,” “will,” “projections,” “estimate,” or other words of similar import. Similarly, statements that describe future financial performance or plans or strategies are forward-looking statements. Such forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements. Some, but not all, of the risks and uncertainties of Alliant Energy, IPL and WPL that could materially affect actual results include:

• | IPL’s and WPL’s ability to obtain adequate and timely rate relief to allow for, among other things, the recovery of and/or the return on costs, including fuel costs, operating costs, transmission costs, deferred expenditures, deferred tax assets, tax expense, capital expenditures, and remaining costs related to EGUs that may be permanently closed and certain other retired assets, decreases in sales volumes, earning their authorized rates of return, and the payments to their parent of expected levels of dividends;

• | federal and state regulatory or governmental actions, including the impact of legislation, and regulatory agency orders;

• | the direct or indirect effects resulting from the COVID-19 pandemic on sales volumes, margins, operations, employees, contractors, vendors, the ability to complete construction projects, supply chains, customers’ inability to pay bills, suspension of disconnects and waiving of late fees applied to past due accounts, the market value of the assets that fund pension plans and the potential for additional funding requirements, the ability of counterparties to meet their obligations, compliance with regulatory requirements, the ability to implement regulatory plans, economic conditions and access to capital markets;

• | the impact of customer- and third party-owned generation, including alternative electric suppliers, in IPL’s and WPL’s service territories on system reliability, operating expenses and customers’ demand for electricity;

• | the impact of energy efficiency, franchise retention and customer disconnects on sales volumes and margins;

• | the impact that price changes may have on IPL’s and WPL’s customers’ demand for electric, gas and steam services and their ability to pay their bills;

• | the ability to utilize tax credits and net operating losses generated to date, and those that may be generated in the future, before they expire;

• | the direct or indirect effects resulting from terrorist incidents, including physical attacks and cyber attacks, or responses to such incidents;

• | the impact of penalties or third-party claims related to, or in connection with, a failure to maintain the security of personally identifiable information, including associated costs to notify affected persons and to mitigate their information security concerns;

• | any material post-closing payments related to any past asset divestitures, including the sale of Whiting Petroleum, which could result from, among other things, indemnification agreements, warranties, guarantees or litigation;

| 1 |

Table of Contents

• | employee workforce factors, including changes in key executives, ability to hire and retain employees with specialized skills, ability to create desired corporate culture, collective bargaining agreements and negotiations, work stoppages or restructurings;

• | weather effects on results of utility operations;

• | issues associated with environmental remediation and environmental compliance, including compliance with all environmental and emissions permits, the Coal Combustion Residuals Rule, future changes in environmental laws and regulations, including federal, state or local regulations for carbon dioxide emissions reductions from new and existing fossil-fueled EGUs, and litigation associated with environmental requirements;

• | increased pressure from customers, investors and other stakeholders to more rapidly reduce carbon dioxide emissions;

• | the ability to defend against environmental claims brought by state and federal agencies, such as the EPA, state natural resources agencies or third parties, such as the Sierra Club, and the impact on operating expenses of defending and resolving such claims;

• | continued access to the capital markets on competitive terms and rates, and the actions of credit rating agencies;

• | inflation and interest rates;

• | the ability to complete construction of solar projects within the cost caps set by regulators and to meet all requirements to qualify for the full level of renewable tax credits;

• | changes in the price of delivered natural gas, purchased electricity and coal due to shifts in supply and demand caused by market conditions and regulations;

• | disruptions in the supply and delivery of natural gas, purchased electricity and coal;

• | the direct or indirect effects resulting from breakdown or failure of equipment in the operation of electric and gas distribution systems, such as mechanical problems and explosions or fires, and compliance with electric and gas transmission and distribution safety regulations, including regulations promulgated by the Pipeline and Hazardous Materials Safety Administration;

• | issues related to the availability and operations of EGUs, including start-up risks, breakdown or failure of equipment, performance below expected or contracted levels of output or efficiency, operator error, employee safety, transmission constraints, compliance with mandatory reliability standards and risks related to recovery of resulting incremental costs through rates;

• | impacts that excessive heat, storms or natural disasters may have on Alliant Energy’s, IPL’s and WPL’s operations and recovery of costs associated with restoration activities, including those related to the August 2020 derecho windstorm, or on the operations of Alliant Energy’s investments;

• | Alliant Energy’s ability to sustain its dividend payout ratio goal;

• | changes to costs of providing benefits and related funding requirements of pension and OPEB plans due to the market value of the assets that fund the plans, economic conditions, financial market performance, interest rates, timing and form of benefits payments, life expectancies and demographics;

• | material changes in employee-related benefit and compensation costs;

• | risks associated with operation and ownership of non-utility holdings;

• | changes in technology that alter the channels through which customers buy or utilize Alliant Energy’s, IPL’s or WPL’s products and services;

• | impacts on equity income from unconsolidated investments from valuations and potential changes to ATC’s authorized return on equity;

• | impacts of IPL’s future tax benefits from Iowa rate-making practices, including deductions for repairs expenditures, allocation of mixed service costs and state depreciation, and recoverability of the associated regulatory assets from customers, when the differences reverse in future periods;

• | the impacts of changes in tax rates, including adjustments made to deferred tax assets and liabilities;

• | changes to the creditworthiness of counterparties with which Alliant Energy, IPL and WPL have contractual arrangements, including participants in the energy markets and fuel suppliers and transporters;

• | current or future litigation, regulatory investigations, proceedings or inquiries;

• | reputational damage from negative publicity, protests, fines, penalties and other negative consequences resulting in regulatory and/or legal actions;

• | the effect of accounting standards issued periodically by standard-setting bodies;

• | the ability to successfully complete tax audits and changes in tax accounting methods with no material impact on earnings and cash flows; and

• | other factors listed in MDA and Item 1A Risk Factors, as well as Risk Factors in Item 1A in the 2019 Form 10-K.

Alliant Energy, IPL and WPL each assume no obligation, and disclaim any duty, to update the forward-looking statements in this report, except as required by law.

| 2 |

Table of Contents
PART I. FINANCIAL INFORMATION
ITEM 1. CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)
ALLIANT ENERGY CORPORATION
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

| For the Three Months |  | For the Nine Months
| Ended September 30, |  | Ended September 30,
| 2020 |  | 2019 |  | 2020 |  | 2019
| (in millions, except per share amounts)
Revenues: |  |  |  |  |  |  |
Electric utility |  | $852 |  |  |  | $916 |  |  |  | $2,257 |  |  |  | $2,350 |
Gas utility | 42 |  |  | 42 |  |  | 253 |  |  | 323 |
Other utility | 10 |  |  | 11 |  |  | 32 |  |  | 33 |
Non-utility | 16 |  |  | 21 |  |  | 57 |  |  | 62 |
Total revenues | 920 |  |  | 990 |  |  | 2,599 |  |  | 2,768 |
Operating expenses: |  |  |  |  |  |  |
Electric production fuel and purchased power | 179 |  |  | 219 |  |  | 527 |  |  | 602 |
Electric transmission service | 132 |  |  | 127 |  |  | 326 |  |  | 363 |
Cost of gas sold | 11 |  |  | 9 |  |  | 117 |  |  | 151 |
Other operation and maintenance | 143 |  |  | 174 |  |  | 465 |  |  | 527 |
Depreciation and amortization | 156 |  |  | 144 |  |  | 454 |  |  | 424 |
Taxes other than income taxes | 27 |  |  | 27 |  |  | 82 |  |  | 84 |
Total operating expenses | 648 |  |  | 700 |  |  | 1,971 |  |  | 2,151 |
Operating income | 272 |  |  | 290 |  |  | 628 |  |  | 617 |
Other (income) and deductions: |  |  |  |  |  |  |
Interest expense | 68 |  |  | 68 |  |  | 207 |  |  | 204 |
Equity income from unconsolidated investments, net | (15 | ) |  | (12 | ) |  | (46 | ) |  | (35 | )
Allowance for funds used during construction | (13 | ) |  | (22 | ) |  | (51 | ) |  | (66 | )
Other | 3 |  |  | 4 |  |  | 7 |  |  | 11 |
Total other (income) and deductions | 43 |  |  | 38 |  |  | 117 |  |  | 114 |
Income before income taxes | 229 |  |  | 252 |  |  | 511 |  |  | 503 |
Income tax expense (benefit) | (20 | ) |  | 23 |  |  | (47 | ) |  | 49 |
Net income | 249 |  |  | 229 |  |  | 558 |  |  | 454 |
Preferred dividend requirements of Interstate Power and Light Company | 3 |  |  | 3 |  |  | 8 |  |  | 8 |
Net income attributable to Alliant Energy common shareowners |  | $246 |  |  |  | $226 |  |  |  | $550 |  |  |  | $446 |
Weighted average number of common shares outstanding: |  |  |  |  |  |  |
Basic | 249.7 |  |  | 239.1 |  |  | 247.9 |  |  | 237.7 |
Diluted | 250.0 |  |  | 239.9 |  |  | 248.1 |  |  | 238.2 |
Earnings per weighted average common share attributable to Alliant Energy common shareowners: |  |  |  |  |  |  |
Basic |  | $0.99 |  |  |  | $0.95 |  |  |  | $2.22 |  |  |  | $1.88 |
Diluted |  | $0.98 |  |  |  | $0.94 |  |  |  | $2.22 |  |  |  | $1.87 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 3 |

Table of Contents
ALLIANT ENERGY CORPORATION
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

| September 30, 2020 |  | December 31, 2019
| (in millions, except per share and share amounts)
ASSETS |  |  |
Current assets: |  |  |
Cash and cash equivalents |  | $189 |  |  |  | $16 |
Accounts receivable, less allowance for expected credit losses | 399 |  |  | 402 |
Production fuel, at weighted average cost | 62 |  |  | 78 |
Gas stored underground, at weighted average cost | 48 |  |  | 49 |
Materials and supplies, at weighted average cost | 113 |  |  | 100 |
Regulatory assets | 74 |  |  | 87 |
Prepaid gross receipts tax | 30 |  |  | 42 |
Other | 118 |  |  | 102 |
Total current assets | 1,033 |  |  | 876 |
Property, plant and equipment, net | 14,199 |  |  | 13,527 |
Investments: |  |  |
ATC Holdings | 328 |  |  | 320 |
Other | 150 |  |  | 148 |
Total investments | 478 |  |  | 468 |
Other assets: |  |  |
Regulatory assets | 1,762 |  |  | 1,758 |
Deferred charges and other | 68 |  |  | 72 |
Total other assets | 1,830 |  |  | 1,830 |
Total assets |  | $17,540 |  |  |  | $16,701 |

LIABILITIES AND EQUITY |  |  |
Current liabilities: |  |  |
Current maturities of long-term debt |  | $7 |  |  |  | $657 |
Commercial paper | 422 |  |  | 337 |
Accounts payable | 417 |  |  | 422 |
Regulatory liabilities | 163 |  |  | 212 |
Other | 286 |  |  | 426 |
Total current liabilities | 1,295 |  |  | 2,054 |
Long-term debt, net (excluding current portion) | 6,574 |  |  | 5,533 |
Other liabilities: |  |  |
Deferred tax liabilities | 1,803 |  |  | 1,714 |
Regulatory liabilities | 1,188 |  |  | 1,212 |
Pension and other benefit obligations | 423 |  |  | 484 |
Other | 348 |  |  | 299 |
Total other liabilities | 3,762 |  |  | 3,709 |
Commitments and contingencies (Note 13) |  |  |  |  |
Equity: |  |  |
Alliant Energy Corporation common equity: |  |  |
Common stock - $0.01 par value - 480,000,000 shares authorized; 249,760,663 and 245,022,800 shares | 2 |  |  | 2 |
Additional paid-in capital | 2,693 |  |  | 2,446 |
Retained earnings | 3,026 |  |  | 2,766 |
Accumulated other comprehensive income (loss) | (1 | ) |  | 1 |
Shares in deferred compensation trust - 374,246 and 381,232 shares at a weighted average cost of $28.28 and $26.24 per share | (11 | ) |  | (10 | )
Total Alliant Energy Corporation common equity | 5,709 |  |  | 5,205 |
Cumulative preferred stock of Interstate Power and Light Company | 200 |  |  | 200 |
Total equity | 5,909 |  |  | 5,405 |
Total liabilities and equity |  | $17,540 |  |  |  | $16,701 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 4 |

Table of Contents
ALLIANT ENERGY CORPORATION
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

| For the Nine Months
| Ended September 30,
| 2020 |  | 2019
| (in millions)
Cash flows from operating activities: |  |  |
Net income |  | $558 |  |  |  | $454 |
Adjustments to reconcile net income to net cash flows from operating activities: |  |  |
Depreciation and amortization | 454 |  |  | 424 |
Deferred tax expense (benefit) and tax credits | (48 | ) |  | 53 |
Equity component of allowance for funds used during construction | (36 | ) |  | (46 | )
Other | 19 |  |  | 17 |
Other changes in assets and liabilities: |  |  |
Accounts receivable | (316 | ) |  | (359 | )
Regulatory liabilities | (72 | ) |  | (12 | )
Deferred income taxes | 143 |  |  | 45 |
Pension and other benefit obligations | (61 | ) |  | (33 | )
DAEC PPA amendment buyout payment | (110 | ) |  | — |
Other | (95 | ) |  | (34 | )
Net cash flows from operating activities | 436 |  |  | 509 |
Cash flows used for investing activities: |  |  |
Construction and acquisition expenditures: |  |  |
Utility business | (935 | ) |  | (1,004 | )
Other | (39 | ) |  | (71 | )
Cash receipts on sold receivables | 318 |  |  | 256 |
Other | (23 | ) |  | (42 | )
Net cash flows used for investing activities | (679 | ) |  | (861 | )
Cash flows from financing activities: |  |  |
Common stock dividends | (281 | ) |  | (253 | )
Proceeds from issuance of common stock, net | 241 |  |  | 185 |
Proceeds from issuance of long-term debt | 1,050 |  |  | 950 |
Payments to retire long-term debt | (654 | ) |  | (253 | )
Net change in commercial paper | 85 |  |  | (92 | )
Other | (22 | ) |  | (11 | )
Net cash flows from financing activities | 419 |  |  | 526 |
Net increase in cash, cash equivalents and restricted cash | 176 |  |  | 174 |
Cash, cash equivalents and restricted cash at beginning of period | 18 |  |  | 26 |
Cash, cash equivalents and restricted cash at end of period |  | $194 |  |  |  | $200 |
Supplemental cash flows information: |  |  |
Cash (paid) refunded during the period for: |  |  |
Interest |  | ($197 | ) |  |  | ($195 | )
Income taxes, net |  | $6 |  |  |  | $1 |
Significant non-cash investing and financing activities: |  |  |
Accrued capital expenditures |  | $202 |  |  |  | $254 |
Beneficial interest obtained in exchange for securitized accounts receivable |  | $201 |  |  |  | $237 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 5 |

Table of Contents
INTERSTATE POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

| For the Three Months |  | For the Nine Months
| Ended September 30, |  | Ended September 30,
| 2020 |  | 2019 |  | 2020 |  | 2019
| (in millions)
Revenues: |  |  |  |  |  |  |
Electric utility |  | $519 |  |  |  | $561 |  |  |  | $1,332 |  |  |  | $1,373 |
Gas utility | 24 |  |  | 25 |  |  | 141 |  |  | 188 |
Steam and other | 10 |  |  | 11 |  |  | 31 |  |  | 32 |
Total revenues | 553 |  |  | 597 |  |  | 1,504 |  |  | 1,593 |
Operating expenses: |  |  |  |  |  |  |
Electric production fuel and purchased power | 102 |  |  | 127 |  |  | 304 |  |  | 339 |
Electric transmission service | 93 |  |  | 92 |  |  | 212 |  |  | 257 |
Cost of gas sold | 6 |  |  | 6 |  |  | 63 |  |  | 80 |
Other operation and maintenance | 85 |  |  | 100 |  |  | 269 |  |  | 306 |
Depreciation and amortization | 89 |  |  | 84 |  |  | 264 |  |  | 243 |
Taxes other than income taxes | 16 |  |  | 14 |  |  | 45 |  |  | 46 |
Total operating expenses | 391 |  |  | 423 |  |  | 1,157 |  |  | 1,271 |
Operating income | 162 |  |  | 174 |  |  | 347 |  |  | 322 |
Other (income) and deductions: |  |  |  |  |  |  |
Interest expense | 35 |  |  | 32 |  |  | 104 |  |  | 93 |
Allowance for funds used during construction | (6 | ) |  | (11 | ) |  | (21 | ) |  | (34 | )
Other | 1 |  |  | 2 |  |  | 3 |  |  | 5 |
Total other (income) and deductions | 30 |  |  | 23 |  |  | 86 |  |  | 64 |
Income before income taxes | 132 |  |  | 151 |  |  | 261 |  |  | 258 |
Income tax expense (benefit) | (19 | ) |  | 7 |  |  | (37 | ) |  | 11 |
Net income | 151 |  |  | 144 |  |  | 298 |  |  | 247 |
Preferred dividend requirements | 3 |  |  | 3 |  |  | 8 |  |  | 8 |
Net income available for common stock |  | $148 |  |  |  | $141 |  |  |  | $290 |  |  |  | $239 |

Earnings per share data is not disclosed given Alliant Energy Corporation is the sole shareowner of all shares of IPL’s common stock outstanding during the periods presented.
Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 6 |

Table of Contents
INTERSTATE POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

| September 30, 2020 |  | December 31, 2019
| (in millions, except per share and share amounts)
ASSETS |
Current assets: |  |  |
Cash and cash equivalents |  | $185 |  |  |  | $9 |
Accounts receivable, less allowance for expected credit losses | 219 |  |  | 203 |
Production fuel, at weighted average cost | 45 |  |  | 47 |
Gas stored underground, at weighted average cost | 21 |  |  | 22 |
Materials and supplies, at weighted average cost | 63 |  |  | 55 |
Regulatory assets | 52 |  |  | 44 |
Other | 53 |  |  | 29 |
Total current assets | 638 |  |  | 409 |
Property, plant and equipment, net | 7,818 |  |  | 7,481 |
Other assets: |  |  |
Regulatory assets | 1,366 |  |  | 1,356 |
Deferred charges and other | 36 |  |  | 31 |
Total other assets | 1,402 |  |  | 1,387 |
Total assets |  | $9,858 |  |  |  | $9,277 |

LIABILITIES AND EQUITY |
Current liabilities: |  |  |
Current maturities of long-term debt |  | $— |  |  |  | $200 |
Accounts payable | 231 |  |  | 207 |
Regulatory liabilities | 117 |  |  | 116 |
Other | 198 |  |  | 307 |
Total current liabilities | 546 |  |  | 830 |
Long-term debt, net (excluding current portion) | 3,344 |  |  | 2,947 |
Other liabilities: |  |  |
Deferred tax liabilities | 1,028 |  |  | 1,008 |
Regulatory liabilities | 574 |  |  | 599 |
Pension and other benefit obligations | 149 |  |  | 168 |
Other | 287 |  |  | 253 |
Total other liabilities | 2,038 |  |  | 2,028 |
Commitments and contingencies (Note 13) |  |  |  |  |
Equity: |  |  |
Interstate Power and Light Company common equity: |  |  |
Common stock - $2.50 par value - 24,000,000 shares authorized; 13,370,788 shares outstanding | 33 |  |  | 33 |
Additional paid-in capital | 2,693 |  |  | 2,348 |
Retained earnings | 1,004 |  |  | 891 |
Total Interstate Power and Light Company common equity | 3,730 |  |  | 3,272 |
Cumulative preferred stock | 200 |  |  | 200 |
Total equity | 3,930 |  |  | 3,472 |
Total liabilities and equity |  | $9,858 |  |  |  | $9,277 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 7 |

Table of Contents
INTERSTATE POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

| For the Nine Months
| Ended September 30,
| 2020 |  | 2019
| (in millions)
Cash flows from operating activities: |  |  |
Net income |  | $298 |  |  |  | $247 |
Adjustments to reconcile net income to net cash flows from operating activities: |  |  |
Depreciation and amortization | 264 |  |  | 243 |
Equity component of allowance for funds used during construction | (15 | ) |  | (25 | )
Deferred tax benefit and tax credits | (42 | ) |  | (14 | )
Other | 6 |  |  | 2 |
Other changes in assets and liabilities: |  |  |
Accounts receivable | (337 | ) |  | (365 | )
Regulatory assets | (32 | ) |  | (13 | )
Deferred income taxes | 62 |  |  | 32 |
Pension and other benefit obligations | (19 | ) |  | (13 | )
DAEC PPA amendment buyout payment | (110 | ) |  | — |
Other | (56 | ) |  | 45 |
Net cash flows from operating activities | 19 |  |  | 139 |
Cash flows used for investing activities: |  |  |
Construction and acquisition expenditures | (465 | ) |  | (696 | )
Cash receipts on sold receivables | 318 |  |  | 256 |
Other | (55 | ) |  | (44 | )
Net cash flows used for investing activities | (202 | ) |  | (484 | )
Cash flows from financing activities: |  |  |
Common stock dividends | (177 | ) |  | (126 | )
Capital contributions from parent | 345 |  |  | 100 |
Proceeds from issuance of long-term debt | 400 |  |  | 600 |
Payments to retire long-term debt | (200 | ) |  | — |
Net change in commercial paper | — |  |  | (50 | )
Other | (9 | ) |  | (6 | )
Net cash flows from financing activities | 359 |  |  | 518 |
Net increase in cash, cash equivalents and restricted cash | 176 |  |  | 173 |
Cash, cash equivalents and restricted cash at beginning of period | 9 |  |  | 12 |
Cash, cash equivalents and restricted cash at end of period |  | $185 |  |  |  | $185 |
Supplemental cash flows information: |  |  |
Cash (paid) refunded during the period for: |  |  |
Interest |  | ($109 | ) |  |  | ($94 | )
Income taxes, net |  | ($12 | ) |  |  | $8 |
Significant non-cash investing and financing activities: |  |  |
Accrued capital expenditures |  | $150 |  |  |  | $180 |
Beneficial interest obtained in exchange for securitized accounts receivable |  | $201 |  |  |  | $237 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 8 |

Table of Contents
WISCONSIN POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED)

| For the Three Months |  | For the Nine Months
| Ended September 30, |  | Ended September 30,
| 2020 |  | 2019 |  | 2020 |  | 2019
| (in millions)
Revenues: |  |  |  |  |  |  |
Electric utility |  | $333 |  |  |  | $355 |  |  |  | $925 |  |  |  | $977 |
Gas utility | 18 |  |  | 17 |  |  | 112 |  |  | 135 |
Other | — |  |  | — |  |  | 1 |  |  | 1 |
Total revenues | 351 |  |  | 372 |  |  | 1,038 |  |  | 1,113 |
Operating expenses: |  |  |  |  |  |  |
Electric production fuel and purchased power | 78 |  |  | 92 |  |  | 223 |  |  | 263 |
Electric transmission service | 39 |  |  | 36 |  |  | 114 |  |  | 106 |
Cost of gas sold | 4 |  |  | 3 |  |  | 53 |  |  | 71 |
Other operation and maintenance | 65 |  |  | 62 |  |  | 172 |  |  | 188 |
Depreciation and amortization | 65 |  |  | 59 |  |  | 186 |  |  | 177 |
Taxes other than income taxes | 11 |  |  | 12 |  |  | 35 |  |  | 35 |
Total operating expenses | 262 |  |  | 264 |  |  | 783 |  |  | 840 |
Operating income | 89 |  |  | 108 |  |  | 255 |  |  | 273 |
Other (income) and deductions: |  |  |  |  |  |  |
Interest expense | 26 |  |  | 25 |  |  | 78 |  |  | 77 |
Allowance for funds used during construction | (6 | ) |  | (11 | ) |  | (29 | ) |  | (31 | )
Other | 1 |  |  | 1 |  |  | 3 |  |  | 4 |
Total other (income) and deductions | 21 |  |  | 15 |  |  | 52 |  |  | 50 |
Income before income taxes | 68 |  |  | 93 |  |  | 203 |  |  | 223 |
Income tax expense (benefit) | (5 | ) |  | 17 |  |  | (17 | ) |  | 40 |
Net income |  | $73 |  |  |  | $76 |  |  |  | $220 |  |  |  | $183 |

Earnings per share data is not disclosed given Alliant Energy Corporation is the sole shareowner of all shares of WPL’s common stock outstanding during the periods presented.
Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 9 |

Table of Contents
WISCONSIN POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED BALANCE SHEETS (UNAUDITED)

| September 30, 2020 |  | December 31, 2019
| (in millions, except per share and share amounts)
ASSETS |  |  |
Current assets: |  |  |
Cash and cash equivalents |  | $2 |  |  |  | $4 |
Accounts receivable, less allowance for expected credit losses | 170 |  |  | 191 |
Production fuel, at weighted average cost | 17 |  |  | 31 |
Gas stored underground, at weighted average cost | 27 |  |  | 27 |
Materials and supplies, at weighted average cost | 48 |  |  | 43 |
Regulatory assets | 22 |  |  | 43 |
Prepaid gross receipts tax | 30 |  |  | 42 |
Other | 22 |  |  | 62 |
Total current assets | 338 |  |  | 443 |
Property, plant and equipment, net | 5,977 |  |  | 5,638 |
Other assets: |  |  |
Regulatory assets | 396 |  |  | 402 |
Deferred charges and other | 33 |  |  | 24 |
Total other assets | 429 |  |  | 426 |
Total assets |  | $6,744 |  |  |  | $6,507 |

LIABILITIES AND EQUITY |  |  |
Current liabilities: |  |  |
Current maturities of long-term debt |  | $— |  |  |  | $150 |
Commercial paper | 139 |  |  | 168 |
Accounts payable | 126 |  |  | 160 |
Regulatory liabilities | 46 |  |  | 96 |
Other | 117 |  |  | 116 |
Total current liabilities | 428 |  |  | 690 |
Long-term debt, net (excluding current portion) | 2,130 |  |  | 1,783 |
Other liabilities: |  |  |
Deferred tax liabilities | 696 |  |  | 626 |
Regulatory liabilities | 614 |  |  | 613 |
Finance lease obligations - Sheboygan Falls Energy Facility | 44 |  |  | 51 |
Pension and other benefit obligations | 189 |  |  | 211 |
Other | 161 |  |  | 169 |
Total other liabilities | 1,704 |  |  | 1,670 |
Commitments and contingencies (Note 13) |  |  |
Equity: |  |  |
Wisconsin Power and Light Company common equity: |  |  |
Common stock - $5 par value - 18,000,000 shares authorized; 13,236,601 shares outstanding | 66 |  |  | 66 |
Additional paid-in capital | 1,459 |  |  | 1,434 |
Retained earnings | 957 |  |  | 864 |
Total Wisconsin Power and Light Company common equity | 2,482 |  |  | 2,364 |
Total liabilities and equity |  | $6,744 |  |  |  | $6,507 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 10 |

Table of Contents
WISCONSIN POWER AND LIGHT COMPANY
CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)

| For the Nine Months
| Ended September 30,
| 2020 |  | 2019
| (in millions)
Cash flows from operating activities: |  |  |
Net income |  | $220 |  |  |  | $183 |
Adjustments to reconcile net income to net cash flows from operating activities: |  |  |
Depreciation and amortization | 186 |  |  | 177 |
Deferred tax expense (benefit) and tax credits | (9 | ) |  | 55 |
Other | (8 | ) |  | (8 | )
Other changes in assets and liabilities: |  |  |
Regulatory liabilities | (61 | ) |  | (29 | )
Deferred income taxes | 79 |  |  | 16 |
Other | (5 | ) |  | (34 | )
Net cash flows from operating activities | 402 |  |  | 360 |
Cash flows used for investing activities: |  |  |
Construction and acquisition expenditures | (470 | ) |  | (308 | )
Other | 5 |  |  | (27 | )
Net cash flows used for investing activities | (465 | ) |  | (335 | )
Cash flows from (used for) financing activities: |  |  |
Common stock dividends | (127 | ) |  | (108 | )
Capital contributions from parent | 25 |  |  | 100 |
Proceeds from issuance of long-term debt | 350 |  |  | 350 |
Payments to retire long-term debt | (150 | ) |  | (250 | )
Net change in commercial paper | (29 | ) |  | (105 | )
Other | (8 | ) |  | (11 | )
Net cash flows from (used for) financing activities | 61 |  |  | (24 | )
Net increase (decrease) in cash, cash equivalents and restricted cash | (2 | ) |  | 1 |
Cash, cash equivalents and restricted cash at beginning of period | 4 |  |  | 9 |
Cash, cash equivalents and restricted cash at end of period |  | $2 |  |  |  | $10 |
Supplemental cash flows information: |  |  |
Cash (paid) refunded during the period for: |  |  |
Interest |  | ($71 | ) |  |  | ($74 | )
Income taxes, net |  | $5 |  |  |  | ($7 | )
Significant non-cash investing and financing activities: |  |  |
Accrued capital expenditures |  | $50 |  |  |  | $70 |

Refer to accompanying Combined Notes to Condensed Consolidated Financial Statements.

| 11 |

Table of Contents
ALLIANT ENERGY CORPORATION
INTERSTATE POWER AND LIGHT COMPANY
WISCONSIN POWER AND LIGHT COMPANY
COMBINED NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS (UNAUDITED)
NOTE 1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
NOTE 1(a) General - The interim unaudited Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Accordingly, certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted, although management believes that the disclosures are adequate to make the information presented not misleading. These Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the latest combined Annual Report on Form 10-K.
In the opinion of management, all adjustments, which unless otherwise noted are normal and recurring in nature, necessary for a fair presentation of the results of operations, financial position and cash flows have been made. Results for the nine months ended September 30, 2020 are not necessarily indicative of results that may be expected for the year ending December 31, 2020.
In March 2020, COVID-19 was declared a global pandemic, which has resulted in widespread travel restrictions, closures of commercial spaces and industrial facilities, and more people working from home in Alliant Energy’s service territories. For the three and nine months ended September 30, 2020, Alliant Energy, IPL and WPL considered the impact of COVID-19 on their overall business operations, financial condition, results of operations and cash flows, along with assumptions and estimates used. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy, IPL and WPL have experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. The degree to which the COVID-19 pandemic may impact Alliant Energy, IPL and WPL in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities.
A change in management’s estimates or assumptions could have a material impact on financial condition and results of operations during the period in which such change occurred. Certain prior period amounts in the Financial Statements and Notes have been reclassified to conform to the current period presentation for comparative purposes.
NOTE 1(b) Cash and Cash Equivalents - At September 30, 2020, Alliant Energy’s and IPL’s cash and cash equivalents included $183 million and $183 million of money market fund investments, with weighted average interest rates of 0.1% and 0.1%, respectively.
NOTE 1(c) Current Expected Credit Losses Estimates - Current expected credit losses are estimated for trade and other receivables and credit exposures on guarantees of the performance by third parties. The current expected credit losses for short-term trade receivables are based on estimates of losses resulting from the inability of customers to make required payments. The methodology used to estimate losses is based on historical write-offs, regional economic conditions, significant events that could impact collectability, such as impacts related to COVID-19, the derecho windstorm and related regulatory actions, and forecasted changes to the accounts receivable aging portfolio and write-offs. The current expected credit losses related to guarantees of the performance by third parties are estimated using both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts.
NOTE 1(d) New Accounting Standards -
Credit Losses - In June 2016, the Financial Accounting Standards Board issued an accounting standard requiring use of a current expected credit loss model rather than an incurred loss method, which is intended to result in more timely recognition of credit losses on trade receivables, certain other assets and off-balance sheet credit exposures. Alliant Energy, IPL and WPL adopted this standard on January 1, 2020 using a modified retrospective method of adoption, which required cumulative effect adjustments to retained earnings on January 1, 2020. IPL and WPL did not record a cumulative effect adjustment to retained earnings and Alliant Energy recorded a pre-tax $12 million (after-tax $9 million) cumulative effect adjustment to decrease retained earnings related to Alliant Energy’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum (refer to Note 13(c) for further discussion). This adjustment is included in “Adoption of new accounting standard” in Alliant Energy’s summary of changes in shareowners’ equity in Note 5 for the nine months ended September 30, 2020.

| 12 |

Table of Contents
NOTE 2. REGULATORY MATTERS
Regulatory Assets and Regulatory Liabilities -
Regulatory assets were comprised of the following items (in millions):

| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $877 |  |  |  | $818 |  |  |  | $829 |  |  |  | $777 |  |  |  | $48 |  |  |  | $41 |
Pension and OPEB costs | 492 |  |  | 524 |  |  | 247 |  |  | 263 |  |  | 245 |  |  | 261 |
Assets retired early | 118 |  |  | 134 |  |  | 79 |  |  | 88 |  |  | 39 |  |  | 46 |
Asset retirement obligations | 115 |  |  | 112 |  |  | 79 |  |  | 76 |  |  | 36 |  |  | 36 |
IPL’s DAEC PPA amendment | 110 |  |  | 108 |  |  | 110 |  |  | 108 |  |  | — |  |  | — |
Derivatives | 20 |  |  | 39 |  |  | 8 |  |  | 18 |  |  | 12 |  |  | 21 |
Emission allowances | 19 |  |  | 21 |  |  | 19 |  |  | 21 |  |  | — |  |  | — |
Other | 85 |  |  | 89 |  |  | 47 |  |  | 49 |  |  | 38 |  |  | 40 |
|  | $1,836 |  |  |  | $1,845 |  |  |  | $1,418 |  |  |  | $1,400 |  |  |  | $418 |  |  |  | $445 |

Regulatory liabilities were comprised of the following items (in millions):

| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Tax-related |  | $746 |  |  |  | $836 |  |  |  | $334 |  |  |  | $351 |  |  |  | $412 |  |  |  | $485 |
Cost of removal obligations | 371 |  |  | 388 |  |  | 241 |  |  | 257 |  |  | 130 |  |  | 131 |
Electric transmission cost recovery | 62 |  |  | 88 |  |  | 30 |  |  | 51 |  |  | 32 |  |  | 37 |
Derivatives | 40 |  |  | 20 |  |  | 27 |  |  | 17 |  |  | 13 |  |  | 3 |
WPL’s West Riverside liquidated damages | 36 |  |  | — |  |  | — |  |  | — |  |  | 36 |  |  | — |
Commodity cost recovery | 22 |  |  | 24 |  |  | 19 |  |  | 9 |  |  | 3 |  |  | 15 |
WPL’s earnings sharing mechanism | 22 |  |  | 22 |  |  | — |  |  | — |  |  | 22 |  |  | 22 |
Other | 52 |  |  | 46 |  |  | 40 |  |  | 30 |  |  | 12 |  |  | 16 |
|  | $1,351 |  |  |  | $1,424 |  |  |  | $691 |  |  |  | $715 |  |  |  | $660 |  |  |  | $709 |

Tax-related - Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities are primarily related to excess deferred tax benefits resulting from the remeasurement of accumulated deferred income taxes caused by Federal Tax Reform. During the nine months ended September 30, 2020, Alliant Energy’s, IPL’s and WPL’s tax-related regulatory liabilities decreased primarily from returning a portion of these excess deferred tax benefits back to customers.
IPL’s DAEC PPA amendment - In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. The payment was recorded as a reduction to “Other current liabilities” on Alliant Energy’s and IPL’s balance sheets and was included in “DAEC PPA amendment buyout payment” in Alliant Energy’s and IPL’s cash flows used for operating activities for the nine months ended September 30, 2020. The buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 through the end of 2025.
Electric transmission cost recovery - In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates, which resulted in a corresponding reduction to “Electric transmission service” expense in Alliant Energy’s and IPL’s income statements for the nine months ended September 30, 2020.
Refer to Note 13(f) for discussion of refunds received by IPL and WPL in 2020 related to MISO transmission owner return on equity complaints.
WPL’s West Riverside liquidated damages - Pursuant to terms included in the related West Riverside construction procurement contracts, WPL reached agreement with the contractor on liquidated damages in the third quarter of 2020. A significant portion of the liquidated damages was settled by WPL offsetting amounts owed to the contractor that were previously withheld for payment, which were non-cash investing activities. The liquidated damages are expected to be returned to WPL’s customers as determined in future regulatory proceedings.
August 2020 Derecho Windstorm - In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration and rebuilding efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. IPL’s current estimate of the total cost of the windstorm is approximately $140 million, and as of September 30, 2020, approximately $130 million was recorded substantially to “Property, plant and equipment, net” on Alliant Energy’s and IPL’s balance sheets. Tax benefits and the incremental operation and maintenance expenses resulting from the windstorm were deferred and recorded

| 13 |

Table of Contents
as a net regulatory liability of $7 million as of September 30, 2020, which is included in “Other” regulatory liabilities in the above table. In November 2020, IPL filed a request with the IUB for utilization of a regulatory account to track certain incremental costs and benefits incurred resulting from the windstorm until IPL’s next rate proceeding.
NOTE 3. RECEIVABLES
Note 3(a) Accounts Receivable - Details for accounts receivable included on the balance sheets were as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Customer |  | $95 |  |  |  | $92 |  |  |  | $— |  |  |  | $— |  |  |  | $86 |  |  |  | $84 |
Unbilled utility revenues | 62 |  |  | 82 |  |  | — |  |  | — |  |  | 62 |  |  | 82 |
Deferred proceeds | 201 |  |  | 188 |  |  | 201 |  |  | 188 |  |  | — |  |  | — |
Other | 54 |  |  | 47 |  |  | 20 |  |  | 16 |  |  | 33 |  |  | 31 |
Allowance for expected credit losses | (13 | ) |  | (7 | ) |  | (2 | ) |  | (1 | ) |  | (11 | ) |  | (6 | )
|  | $399 |  |  |  | $402 |  |  |  | $219 |  |  |  | $203 |  |  |  | $170 |  |  |  | $191 |

Note 3(b) Sales of Accounts Receivable - IPL maintains a Receivables Purchase and Sale Agreement (Receivables Agreement) whereby it may sell its customer accounts receivables, unbilled revenues and certain other accounts receivables to a third party through wholly-owned and consolidated special purpose entities. The transfers of receivables meet the criteria for sale accounting established by the transfer of financial assets accounting rules. As of September 30, 2020, IPL had $109 million of available capacity under its sales of accounts receivable program. IPL’s maximum and average outstanding cash proceeds (based on daily outstanding balances) related to the sales of accounts receivable program for the three and nine months ended September 30 were as follows (in millions):

| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
Maximum outstanding aggregate cash proceeds |  | $1 |  |  |  | $103 |  |  |  | $96 |  |  |  | $108 |
Average outstanding aggregate cash proceeds | 1 |  |  | 45 |  |  | 12 |  |  | 43 |

The attributes of IPL’s receivables sold under the Receivables Agreement were as follows (in millions):

| September 30, 2020 |  | December 31, 2019
Customer accounts receivable |  | $148 |  |  |  | $125 |
Unbilled utility revenues | 67 |  |  | 95 |
Other receivables | — |  |  | 1 |
Receivables sold to third party | 215 |  |  | 221 |
Less: cash proceeds | 1 |  |  | 27 |
Deferred proceeds | 214 |  |  | 194 |
Less: allowance for expected credit losses | 13 |  |  | 6 |
Fair value of deferred proceeds |  | $201 |  |  |  | $188 |

As of September 30, 2020, outstanding receivables past due under the Receivables Agreement were $27 million. Additional attributes of IPL’s receivables sold under the Receivables Agreement for the three and nine months ended September 30 were as follows (in millions):

| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
Collections |  | $561 |  |  |  | $592 |  |  |  | $1,555 |  |  |  | $1,636 |
Write-offs, net of recoveries | 1 |  |  | 3 |  |  | 4 |  |  | 11 |

NOTE 4. INVESTMENTS
Unconsolidated Equity Investments - Alliant Energy’s equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three and nine months ended September 30 was as follows (in millions):

| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
ATC Holdings |  | ($11 | ) |  |  | ($11 | ) |  |  | ($36 | ) |  |  | ($30 | )
Non-utility wind farm in Oklahoma | (2 | ) |  | — |  |  | (6 | ) |  | (3 | )
Other | (2 | ) |  | (1 | ) |  | (4 | ) |  | (2 | )
|  | ($15 | ) |  |  | ($12 | ) |  |  | ($46 | ) |  |  | ($35 | )

| 14 |

Table of Contents
NOTE 5. COMMON EQUITY
Common Share Activity - A summary of Alliant Energy’s common stock activity was as follows:

Shares outstanding, January 1, 2020 | 245,022,800 |
Equity forward agreements | 4,275,127 |
Shareowner Direct Plan | 364,531 |
Equity-based compensation plans | 98,205 |
Shares outstanding, September 30, 2020 | 249,760,663 |

Equity Forward Agreements - In November 2019, Alliant Energy entered into forward sale agreements with a counterparty in connection with a public offering of 4,275,127 shares of Alliant Energy common stock. The initial forward sale price of $52.235 per share was subject to daily adjustment based on a floating interest rate factor, and decreased by other fixed amounts specified in the forward sale agreements. In the first quarter of 2020, Alliant Energy settled $222 million under the forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share. Alliant Energy used the net proceeds from the settlements for general corporate purposes.
Changes in Shareowners’ Equity - A summary of changes in shareowners’ equity was as follows (in millions):

Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Three Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2020 |  | $2 |  |  |  | $2,683 |  |  |  | $2,874 |  |  |  | ($1 | ) |  |  | ($10 | ) |  |  | $200 |  |  |  | $5,748 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 246 |  |  |  |  |  |  |  |  | 246 |
Common stock dividends ($0.38 per share) |  |  |  |  | (94 | ) |  |  |  |  |  |  |  | (94 | )
Shareowner Direct Plan issuances |  |  |  | 6 |  |  |  |  |  |  |  |  |  |  | 6 |
Equity-based compensation plans and other |  |  | 4 |  |  |  |  |  |  | (1 | ) |  |  |  | 3 |
Ending balance, September 30, 2020 |  | $2 |  |  |  | $2,693 |  |  |  | $3,026 |  |  |  | ($1 | ) |  |  | ($11 | ) |  |  | $200 |  |  |  | $5,909 |
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2019 |  | $2 |  |  |  | $2,109 |  |  |  | $2,598 |  |  |  | $1 |  |  |  | ($10 | ) |  |  | $200 |  |  |  | $4,900 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 226 |  |  |  |  |  |  |  |  | 226 |
Common stock dividends ($0.355 per share) |  |  |  |  | (85 | ) |  |  |  |  |  |  |  | (85 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 125 |  |  |  |  |  |  |  |  |  |  | 125 |
Equity-based compensation plans and other |  |  | 3 |  |  |  |  |  |  |  |  |  |  |  | 3 |
Ending balance, September 30, 2019 |  | $2 |  |  |  | $2,237 |  |  |  | $2,739 |  |  |  | $1 |  |  |  | ($10 | ) |  |  | $200 |  |  |  | $5,169 |

| 15 |

Table of Contents

Alliant Energy | Total Alliant Energy Common Equity |  |  |  |
|  |  |  |  |  |  | Accumulated |  | Shares in |  | Cumulative |  |
|  |  | Additional |  |  |  | Other |  | Deferred |  | Preferred |  |
| Common |  | Paid-In |  | Retained |  | Comprehensive |  | Compensation |  | Stock |  | Total
| Stock |  | Capital |  | Earnings |  | Income (Loss) |  | Trust |  | of IPL |  | Equity
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2019 |  | $2 |  |  |  | $2,446 |  |  |  | $2,766 |  |  |  | $1 |  |  |  | ($10 | ) |  |  | $200 |  |  |  | $5,405 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 550 |  |  |  |  |  |  |  |  | 550 |
Common stock dividends ($1.14 per share) |  |  |  |  | (281 | ) |  |  |  |  |  |  |  | (281 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  |  | 241 |  |  |  |  |  |  |  |  |  |  | 241 |
Equity-based compensation plans and other |  |  | 6 |  |  |  |  |  |  | (1 | ) |  |  |  | 5 |
Adoption of new accounting standard, net of tax (refer to Note 1(d)) |  |  |  |  | (9 | ) |  |  |  |  |  |  |  | (9 | )
Other comprehensive loss, net of tax |  |  |  |  |  |  | (2 | ) |  |  |  |  |  | (2 | )
Ending balance, September 30, 2020 |  | $2 |  |  |  | $2,693 |  |  |  | $3,026 |  |  |  | ($1 | ) |  |  | ($11 | ) |  |  | $200 |  |  |  | $5,909 |
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2018 |  | $2 |  |  |  | $2,046 |  |  |  | $2,546 |  |  |  | $2 |  |  |  | ($10 | ) |  |  | $200 |  |  |  | $4,786 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  | 446 |  |  |  |  |  |  |  |  | 446 |
Common stock dividends ($1.065 per share) |  |  |  |  | (253 | ) |  |  |  |  |  |  |  | (253 | )
Equity forward settlements and Shareowner Direct Plan issuances |  |  | 185 |  |  |  |  |  |  |  |  |  |  | 185 |
Equity-based compensation plans and other |  |  | 6 |  |  |  |  |  |  |  |  |  |  |  | 6 |
Other comprehensive loss, net of tax |  |  |  |  |  |  | (1 | ) |  |  |  |  |  | (1 | )
Ending balance, September 30, 2019 |  | $2 |  |  |  | $2,237 |  |  |  | $2,739 |  |  |  | $1 |  |  |  | ($10 | ) |  |  | $200 |  |  |  | $5,169 |

IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Three Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2020 |  | $33 |  |  |  | $2,523 |  |  |  | $915 |  |  |  | $200 |  |  |  | $3,671 |
Net income available for common stock |  |  |  |  | 148 |  |  |  |  | 148 |
Common stock dividends |  |  |  |  | (59 | ) |  |  |  | (59 | )
Capital contributions from parent |  |  | 170 |  |  |  |  |  |  | 170 |
Ending balance, September 30, 2020 |  | $33 |  |  |  | $2,693 |  |  |  | $1,004 |  |  |  | $200 |  |  |  | $3,930 |
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, June 30, 2019 |  | $33 |  |  |  | $2,323 |  |  |  | $789 |  |  |  | $200 |  |  |  | $3,345 |
Net income available for common stock |  |  |  |  | 141 |  |  |  |  | 141 |
Common stock dividends |  |  |  |  | (42 | ) |  |  |  | (42 | )
Ending balance, September 30, 2019 |  | $33 |  |  |  | $2,323 |  |  |  | $888 |  |  |  | $200 |  |  |  | $3,444 |

IPL | Total IPL Common Equity |  |  |  |
|  |  | Additional |  |  |  | Cumulative |  |
| Common |  | Paid-In |  | Retained |  | Preferred |  | Total
| Stock |  | Capital |  | Earnings |  | Stock |  | Equity
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2019 |  | $33 |  |  |  | $2,348 |  |  |  | $891 |  |  |  | $200 |  |  |  | $3,472 |
Net income available for common stock |  |  |  |  | 290 |  |  |  |  | 290 |
Common stock dividends |  |  |  |  | (177 | ) |  |  |  | (177 | )
Capital contributions from parent |  |  | 345 |  |  |  |  |  |  | 345 |
Ending balance, September 30, 2020 |  | $33 |  |  |  | $2,693 |  |  |  | $1,004 |  |  |  | $200 |  |  |  | $3,930 |
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |
Beginning balance, December 31, 2018 |  | $33 |  |  |  | $2,223 |  |  |  | $775 |  |  |  | $200 |  |  |  | $3,231 |
Net income available for common stock |  |  |  |  | 239 |  |  |  |  | 239 |
Common stock dividends |  |  |  |  | (126 | ) |  |  |  | (126 | )
Capital contributions from parent |  |  | 100 |  |  |  |  |  |  | 100 |
Ending balance, September 30, 2019 |  | $33 |  |  |  | $2,323 |  |  |  | $888 |  |  |  | $200 |  |  |  | $3,444 |

| 16 |

Table of Contents

WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Beginning balance, June 30, 2020 |  | $66 |  |  |  | $1,459 |  |  |  | $927 |  |  |  | $2,452 |
Net income |  |  |  |  | 73 |  |  | 73 |
Common stock dividends |  |  |  |  | (43 | ) |  | (43 | )
Ending balance, September 30, 2020 |  | $66 |  |  |  | $1,459 |  |  |  | $957 |  |  |  | $2,482 |
Three Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, June 30, 2019 |  | $66 |  |  |  | $1,309 |  |  |  | $810 |  |  |  | $2,185 |
Net income |  |  |  |  | 76 |  |  | 76 |
Common stock dividends |  |  |  |  | (36 | ) |  | (36 | )
Capital contributions from parent |  |  | 100 |  |  |  |  | 100 |
Ending balance, September 30, 2019 |  | $66 |  |  |  | $1,409 |  |  |  | $850 |  |  |  | $2,325 |

WPL |  |  | Additional |  |  |  | Total
| Common |  | Paid-In |  | Retained |  | Common
| Stock |  | Capital |  | Earnings |  | Equity
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Beginning balance, December 31, 2019 |  | $66 |  |  |  | $1,434 |  |  |  | $864 |  |  |  | $2,364 |
Net income |  |  |  |  | 220 |  |  | 220 |
Common stock dividends |  |  |  |  | (127 | ) |  | (127 | )
Capital contributions from parent |  |  | 25 |  |  |  |  | 25 |
Ending balance, September 30, 2020 |  | $66 |  |  |  | $1,459 |  |  |  | $957 |  |  |  | $2,482 |
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |
Beginning balance, December 31, 2018 |  | $66 |  |  |  | $1,309 |  |  |  | $775 |  |  |  | $2,150 |
Net income |  |  |  |  | 183 |  |  | 183 |
Common stock dividends |  |  |  |  | (108 | ) |  | (108 | )
Capital contributions from parent |  |  | 100 |  |  |  |  | 100 |
Ending balance, September 30, 2019 |  | $66 |  |  |  | $1,409 |  |  |  | $850 |  |  |  | $2,325 |

NOTE 6. DEBT
NOTE 6(a) Short-term Debt - Information regarding Alliant Energy’s, IPL’s and WPL’s commercial paper, and Alliant Energy’s and WPL’s borrowings under the single credit facility, which currently expires in August 2023, classified as short-term debt was as follows (dollars in millions):

September 30, 2020 | Alliant Energy |  | IPL |  | WPL
Amount outstanding | $422 |  | $— |  | $139
Weighted average interest rates | 0.2% |  | N/A |  | 0.1%
Available credit facility capacity | $578 |  | $250 |  | $161

| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Maximum amount outstanding (based on daily outstanding balances) |  | $422 |  |  |  | $472 |  |  |  | $— |  |  |  | $— |  |  |  | $139 |  |  |  | $90 |
Average amount outstanding (based on daily outstanding balances) |  | $252 |  |  |  | $400 |  |  |  | $— |  |  |  | $— |  |  |  | $83 |  |  |  | $27 |
Weighted average interest rates | 0.2% |  | 2.5% |  | N/A |  | N/A |  | 0.2% |  | 2.3%
Nine Months Ended September 30 |  |  |  |  |  |  |  |  |  |  |
Maximum amount outstanding (based on daily outstanding balances) |  | $463 |  |  |  | $601 |  |  |  | $8 |  |  |  | $50 |  |  |  | $212 |  |  |  | $195 |
Average amount outstanding (based on daily outstanding balances) |  | $252 |  |  |  | $476 |  |  |  | $— |  |  |  | $— |  |  |  | $86 |  |  |  | $102 |
Weighted average interest rates | 1.1% |  | 2.6% |  | 0.5% |  | 2.8% |  | 1.2% |  | 2.5%

NOTE 6(b) Long-term Debt - In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor) and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020. AEF’s current term loan credit agreement expires in March 2022 and includes substantially the same financial covenants that are included in Alliant Energy’s credit facility agreement.

| 17 |

Table of Contents
In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.
In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.
NOTE 7. REVENUES
Disaggregation of revenues from contracts with customers, which correlates to revenues for each reportable segment, was as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
Three Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential |  | $328 |  |  |  | $332 |  |  |  | $189 |  |  |  | $196 |  |  |  | $139 |  |  |  | $136 |
Retail - commercial | 210 |  |  | 231 |  |  | 142 |  |  | 158 |  |  | 68 |  |  | 73 |
Retail - industrial | 241 |  |  | 264 |  |  | 149 |  |  | 158 |  |  | 92 |  |  | 106 |
Wholesale | 47 |  |  | 50 |  |  | 17 |  |  | 18 |  |  | 30 |  |  | 32 |
Bulk power and other | 26 |  |  | 39 |  |  | 22 |  |  | 31 |  |  | 4 |  |  | 8 |
Total Electric Utility | 852 |  |  | 916 |  |  | 519 |  |  | 561 |  |  | 333 |  |  | 355 |
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 22 |  |  | 20 |  |  | 12 |  |  | 12 |  |  | 10 |  |  | 8 |
Retail - commercial | 10 |  |  | 10 |  |  | 6 |  |  | 6 |  |  | 4 |  |  | 4 |
Retail - industrial | 2 |  |  | 3 |  |  | 1 |  |  | 2 |  |  | 1 |  |  | 1 |
Transportation/other | 8 |  |  | 9 |  |  | 5 |  |  | 5 |  |  | 3 |  |  | 4 |
Total Gas Utility | 42 |  |  | 42 |  |  | 24 |  |  | 25 |  |  | 18 |  |  | 17 |
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 8 |  |  | 9 |  |  | 8 |  |  | 9 |  |  | — |  |  | — |
Other utility | 2 |  |  | 2 |  |  | 2 |  |  | 2 |  |  | — |  |  | — |
Total Other Utility | 10 |  |  | 11 |  |  | 10 |  |  | 11 |  |  | — |  |  | — |
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 16 |  |  | 21 |  |  | — |  |  | — |  |  | — |  |  | — |
Total Non-Utility and Other | 16 |  |  | 21 |  |  | — |  |  | — |  |  | — |  |  | — |
Total revenues |  | $920 |  |  |  | $990 |  |  |  | $553 |  |  |  | $597 |  |  |  | $351 |  |  |  | $372 |

| Alliant Energy |  | IPL |  | WPL
Nine Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Electric Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential |  | $845 |  |  |  | $840 |  |  |  | $472 |  |  |  | $470 |  |  |  | $373 |  |  |  | $370 |
Retail - commercial | 556 |  |  | 583 |  |  | 371 |  |  | 386 |  |  | 185 |  |  | 197 |
Retail - industrial | 648 |  |  | 686 |  |  | 384 |  |  | 392 |  |  | 264 |  |  | 294 |
Wholesale | 127 |  |  | 137 |  |  | 44 |  |  | 49 |  |  | 83 |  |  | 88 |
Bulk power and other | 81 |  |  | 104 |  |  | 61 |  |  | 76 |  |  | 20 |  |  | 28 |
Total Electric Utility | 2,257 |  |  | 2,350 |  |  | 1,332 |  |  | 1,373 |  |  | 925 |  |  | 977 |
Gas Utility: |  |  |  |  |  |  |  |  |  |  |
Retail - residential | 146 |  |  | 187 |  |  | 79 |  |  | 109 |  |  | 67 |  |  | 78 |
Retail - commercial | 70 |  |  | 90 |  |  | 38 |  |  | 50 |  |  | 32 |  |  | 40 |
Retail - industrial | 8 |  |  | 10 |  |  | 5 |  |  | 7 |  |  | 3 |  |  | 3 |
Transportation/other | 29 |  |  | 36 |  |  | 19 |  |  | 22 |  |  | 10 |  |  | 14 |
Total Gas Utility | 253 |  |  | 323 |  |  | 141 |  |  | 188 |  |  | 112 |  |  | 135 |
Other Utility: |  |  |  |  |  |  |  |  |  |  |
Steam | 27 |  |  | 27 |  |  | 27 |  |  | 27 |  |  | — |  |  | — |
Other utility | 5 |  |  | 6 |  |  | 4 |  |  | 5 |  |  | 1 |  |  | 1 |
Total Other Utility | 32 |  |  | 33 |  |  | 31 |  |  | 32 |  |  | 1 |  |  | 1 |
Non-Utility and Other: |  |  |  |  |  |  |  |  |  |  |
Transportation and other | 57 |  |  | 62 |  |  | — |  |  | — |  |  | — |  |  | — |
Total Non-Utility and Other | 57 |  |  | 62 |  |  | — |  |  | — |  |  | — |  |  | — |
Total revenues |  | $2,599 |  |  |  | $2,768 |  |  |  | $1,504 |  |  |  | $1,593 |  |  |  | $1,038 |  |  |  | $1,113 |

| 18 |

Table of Contents
NOTE 8. INCOME TAXES
Income Tax Rates - Overall effective income tax rates, which were computed by dividing income tax expense (benefit) by income before income taxes, were as follows. The effective income tax rates were different than the federal statutory rate primarily due to state income taxes, production tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. The decreases in overall effective income tax rates for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were primarily due to increases in production tax credits as a result of increased wind production in 2020 and increased amortization of excess deferred taxes primarily at WPL, which were used to offset increases in WPL’s 2020 increased revenue requirements.

| Alliant Energy |  | IPL |  | WPL
| Three Months |  | Nine Months |  | Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Overall income tax rate | (9%) |  | 9% |  | (9%) |  | 10% |  | (14%) |  | 5% |  | (14%) |  | 4% |  | (7%) |  | 18% |  | (8%) |  | 18%

Deferred Tax Assets and Liabilities -
Carryforwards - At September 30, 2020, carryforwards and expiration dates were estimated as follows (in millions):

| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
Federal net operating losses | 2037 |  |  | $371 |  |  |  | $343 |  |  |  | $3 |
State net operating losses | 2020-2040 |  | 623 |  |  | 10 |  |  | 2 |
Federal tax credits | 2022-2040 |  | 446 |  |  | 252 |  |  | 173 |

NOTE 9. BENEFIT PLANS
NOTE 9(a) Pension and OPEB Plans -
Net Periodic Benefit Costs - The components of net periodic benefit costs for sponsored defined benefit pension and OPEB plans for the three and nine months ended September 30 are included below (in millions). For IPL and WPL, amounts represent those for their plan participants covered under plans they sponsor, as well as amounts directly assigned to them related to certain participants in the Alliant Energy and Corporate Services sponsored plans.

| Defined Benefit Pension Plans |  | OPEB Plans
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
Alliant Energy | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Service cost |  | $3 |  |  |  | $2 |  |  |  | $8 |  |  |  | $7 |  |  |  | $1 |  |  |  | $1 |  |  |  | $3 |  |  |  | $3 |
Interest cost | 10 |  |  | 13 |  |  | 32 |  |  | 37 |  |  | 2 |  |  | 2 |  |  | 5 |  |  | 6 |
Expected return on plan assets | (17 | ) |  | (15 | ) |  | (52 | ) |  | (45 | ) |  | (1 | ) |  | (1 | ) |  | (4 | ) |  | (4 | )
Amortization of actuarial loss | 9 |  |  | 9 |  |  | 26 |  |  | 27 |  |  | — |  |  | 1 |  |  | 2 |  |  | 2 |
Settlement losses (a) | — |  |  | — |  |  | 4 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |
|  | $5 |  |  |  | $9 |  |  |  | $18 |  |  |  | $26 |  |  |  | $2 |  |  |  | $3 |  |  |  | $6 |  |  |  | $7 |

| Defined Benefit Pension Plans |  | OPEB Plans
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
IPL | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Service cost |  | $2 |  |  |  | $1 |  |  |  | $5 |  |  |  | $4 |  |  |  | $— |  |  |  | $— |  |  |  | $1 |  |  |  | $1 |
Interest cost | 5 |  |  | 6 |  |  | 15 |  |  | 17 |  |  | 1 |  |  | 1 |  |  | 2 |  |  | 3 |
Expected return on plan assets | (8 | ) |  | (7 | ) |  | (24 | ) |  | (21 | ) |  | (1 | ) |  | (1 | ) |  | (3 | ) |  | (3 | )
Amortization of actuarial loss | 4 |  |  | 4 |  |  | 11 |  |  | 12 |  |  | — |  |  | 1 |  |  | 1 |  |  | 1 |
|  | $3 |  |  |  | $4 |  |  |  | $7 |  |  |  | $12 |  |  |  | $— |  |  |  | $1 |  |  |  | $1 |  |  |  | $2 |

| Defined Benefit Pension Plans |  | OPEB Plans
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
WPL | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Service cost |  | $1 |  |  |  | $1 |  |  |  | $3 |  |  |  | $3 |  |  |  | $— |  |  |  | $— |  |  |  | $1 |  |  |  | $1 |
Interest cost | 5 |  |  | 5 |  |  | 14 |  |  | 16 |  |  | 1 |  |  | 1 |  |  | 2 |  |  | 3 |
Expected return on plan assets | (8 | ) |  | (6 | ) |  | (23 | ) |  | (20 | ) |  | (1 | ) |  | — |  |  | (1 | ) |  | (1 | )
Amortization of actuarial loss | 4 |  |  | 4 |  |  | 12 |  |  | 13 |  |  | 1 |  |  | — |  |  | 2 |  |  | 1 |
|  | $2 |  |  |  | $4 |  |  |  | $6 |  |  |  | $12 |  |  |  | $1 |  |  |  | $1 |  |  |  | $4 |  |  |  | $4 |

(a) | Settlement losses related to payments made to retired executives of Alliant Energy.

NOTE 9(b) Equity-based Compensation Plans - A summary of compensation expense, including amounts allocated to IPL and WPL, and the related income tax benefits recognized for share-based compensation awards for the three and nine months ended September 30 was as follows (in millions):

| 19 |

Table of Contents

| Alliant Energy |  | IPL |  | WPL
| Three Months |  | Nine Months |  | Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Compensation expense |  | $5 |  |  |  | $8 |  |  |  | $10 |  |  |  | $16 |  |  |  | $3 |  |  |  | $4 |  |  |  | $6 |  |  |  | $9 |  |  |  | $2 |  |  |  | $3 |  |  |  | $4 |  |  |  | $6 |
Income tax benefits | 1 |  |  | 2 |  |  | 3 |  |  | 4 |  |  | 1 |  |  | 1 |  |  | 2 |  |  | 2 |  |  | — |  |  | 1 |  |  | 1 |  |  | 2 |

As of September 30, 2020, Alliant Energy’s, IPL’s and WPL’s total unrecognized compensation cost related to share-based compensation awards was $7 million, $4 million and $3 million, respectively, which is expected to be recognized over a weighted average period of between 1 year and 2 years.
For the nine months ended September 30, 2020, performance shares, performance restricted stock units and restricted stock units were granted to key employees as follows. These shares and units will be paid out in shares of common stock, and are therefore accounted for as equity awards. As of September 30, 2020, 276,070 shares were included in the calculation of diluted EPS related to the nonvested equity awards.

|  |  | Weighted Average
| Grants |  | Grant Date Fair Value
Performance shares | 55,303 |  |  |  | $64.04 |
Performance restricted stock units | 55,303 |  |  | 59.47 |
Restricted stock units | 60,284 |  |  | 59.49 |

NOTE 10. ASSET RETIREMENT OBLIGATIONS
A reconciliation of the changes in asset retirement obligations associated with long-lived assets for the nine months ended September 30, 2020 is as follows (in millions):

| Alliant Energy |  | IPL
Balance, January 1 |  | $196 |  |  |  | $134 |
Revisions in estimated cash flows | 1 |  |  | — |
Liabilities settled | (7 | ) |  | (5 | )
Liabilities incurred (a) | 38 |  |  | 38 |
Accretion expense | 5 |  |  | 4 |
Balance, September 30 |  | $233 |  |  |  | $171 |

(a) | During the nine months ended September 30, 2020, Alliant Energy and IPL recognized additional asset retirement obligations related to IPL’s newly constructed Whispering Willow North, Golden Plains and Richland wind sites. The increases in asset retirement obligations resulted in corresponding increases in property, plant and equipment, net on the respective balance sheets.

NOTE 11. DERIVATIVE INSTRUMENTS
Commodity Derivatives -
Notional Amounts - As of September 30, 2020, gross notional amounts and settlement/delivery years related to outstanding swap contracts, option contracts, physical forward contracts and FTRs that were accounted for as commodity derivative instruments were as follows (units in thousands):

| FTRs |  | Natural Gas |  | Coal |  | Diesel Fuel
| MWhs |  | Years |  | Dths |  | Years |  | Tons |  | Years |  | Gallons |  | Years
Alliant Energy | 14,365 |  |  | 2020-2021 |  | 218,581 |  |  | 2020-2028 |  | 8,151 |  |  | 2020-2023 |  | 6,174 |  |  | 2020-2022
IPL | 5,401 |  |  | 2020-2021 |  | 114,747 |  |  | 2020-2028 |  | 3,373 |  |  | 2020-2023 |  | — |  |  | —
WPL | 8,964 |  |  | 2020-2021 |  | 103,834 |  |  | 2020-2027 |  | 4,778 |  |  | 2020-2023 |  | 6,174 |  |  | 2020-2022

Financial Statement Presentation - Derivative instruments are recorded at fair value each reporting date on the balance sheets as assets or liabilities as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Current derivative assets |  | $33 |  |  |  | $16 |  |  |  | $23 |  |  |  | $12 |  |  |  | $10 |  |  |  | $4 |
Non-current derivative assets | 15 |  |  | 11 |  |  | 11 |  |  | 10 |  |  | 4 |  |  | 1 |
Current derivative liabilities | 6 |  |  | 19 |  |  | 2 |  |  | 9 |  |  | 4 |  |  | 10 |
Non-current derivative liabilities | 13 |  |  | 19 |  |  | 6 |  |  | 9 |  |  | 7 |  |  | 10 |

| 20 |

Table of Contents
Credit Risk-related Contingent Features - Various agreements contain credit risk-related contingent features, including requirements to maintain certain credit ratings and/or limitations on liability positions under the agreements based on credit ratings. Certain of these agreements with credit risk-related contingency features are accounted for as derivative instruments. In the event of a material change in creditworthiness or if liability positions exceed certain contractual limits, credit support may need to be provided in the form of letters of credit or cash collateral up to the amount of exposure under the contracts, or the contracts may need to be unwound and underlying liability positions paid. At September 30, 2020 and December 31, 2019, the aggregate fair value of all derivative instruments with credit risk-related contingent features in a net liability position was not materially different than amounts that would be required to be posted as credit support to counterparties by Alliant Energy, IPL or WPL if the most restrictive credit risk-related contingent features for derivative agreements in a net liability position were triggered.
Balance Sheet Offsetting - The fair value amounts of derivative instruments subject to a master netting arrangement are not netted by counterparty on the balance sheets. However, if the fair value amounts of derivative instruments by counterparty were netted, amounts would not be materially different from gross amounts of derivative assets and derivative liabilities at September 30, 2020 and December 31, 2019. Fair value amounts recognized for the right to reclaim cash collateral (receivable) or the obligation to return cash collateral (payable) are not offset against fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement.
NOTE 12. FAIR VALUE MEASUREMENTS
Fair Value of Financial Instruments - The carrying amounts of current assets and current liabilities approximate fair value because of the short maturity of such financial instruments. Carrying amounts and related estimated fair values of other financial instruments were as follows (in millions):

Alliant Energy | September 30, 2020 |  | December 31, 2019
|  |  | Fair Value |  |  |  | Fair Value
| Carrying |  | Level |  | Level |  | Level |  |  |  | Carrying |  | Level |  | Level |  | Level |  |
| Amount |  | 1 |  | 2 |  | 3 |  | Total |  | Amount |  | 1 |  | 2 |  | 3 |  | Total
Assets: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market fund investments |  | $183 |  |  |  | $183 |  |  |  | $— |  |  |  | $— |  |  |  | $183 |  |  |  | $5 |  |  |  | $5 |  |  |  | $— |  |  |  | $— |  |  |  | $5 |
Derivatives | 48 |  |  | — |  |  | 17 |  |  | 31 |  |  | 48 |  |  | 27 |  |  | — |  |  | 5 |  |  | 22 |  |  | 27 |
Deferred proceeds | 201 |  |  | — |  |  | — |  |  | 201 |  |  | 201 |  |  | 188 |  |  | — |  |  | — |  |  | 188 |  |  | 188 |
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives | 19 |  |  | — |  |  | 18 |  |  | 1 |  |  | 19 |  |  | 38 |  |  | — |  |  | 37 |  |  | 1 |  |  | 38 |
Long-term debt (incl. current maturities) | 6,581 |  |  | — |  |  | 7,849 |  |  | 2 |  |  | 7,851 |  |  | 6,190 |  |  | — |  |  | 6,918 |  |  | 2 |  |  | 6,920 |

IPL | September 30, 2020 |  | December 31, 2019
|  |  | Fair Value |  |  |  | Fair Value
| Carrying |  | Level |  | Level |  | Level |  |  |  | Carrying |  | Level |  | Level |  | Level |  |
| Amount |  | 1 |  | 2 |  | 3 |  | Total |  | Amount |  | 1 |  | 2 |  | 3 |  | Total
Assets: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Money market fund investments |  | $183 |  |  |  | $183 |  |  |  | $— |  |  |  | $— |  |  |  | $183 |  |  |  | $5 |  |  |  | $5 |  |  |  | $— |  |  |  | $— |  |  |  | $5 |
Derivatives | 34 |  |  | — |  |  | 7 |  |  | 27 |  |  | 34 |  |  | 22 |  |  | — |  |  | 3 |  |  | 19 |  |  | 22 |
Deferred proceeds | 201 |  |  | — |  |  | — |  |  | 201 |  |  | 201 |  |  | 188 |  |  | — |  |  | — |  |  | 188 |  |  | 188 |
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives | 8 |  |  | — |  |  | 7 |  |  | 1 |  |  | 8 |  |  | 18 |  |  | — |  |  | 17 |  |  | 1 |  |  | 18 |
Long-term debt (incl. current maturities) | 3,344 |  |  | — |  |  | 3,987 |  |  | — |  |  | 3,987 |  |  | 3,147 |  |  | — |  |  | 3,489 |  |  | — |  |  | 3,489 |

WPL | September 30, 2020 |  | December 31, 2019
|  |  | Fair Value |  |  |  | Fair Value
| Carrying |  | Level |  | Level |  | Level |  |  |  | Carrying |  | Level |  | Level |  | Level |  |
| Amount |  | 1 |  | 2 |  | 3 |  | Total |  | Amount |  | 1 |  | 2 |  | 3 |  | Total
Assets: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives |  | $14 |  |  |  | $— |  |  |  | $10 |  |  |  | $4 |  |  |  | $14 |  |  |  | $5 |  |  |  | $— |  |  |  | $2 |  |  |  | $3 |  |  |  | $5 |
Liabilities: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Derivatives | 11 |  |  | — |  |  | 11 |  |  | — |  |  | 11 |  |  | 20 |  |  | — |  |  | 20 |  |  | — |  |  | 20 |
Long-term debt (incl. current maturities) | 2,130 |  |  | — |  |  | 2,667 |  |  | — |  |  | 2,667 |  |  | 1,933 |  |  | — |  |  | 2,268 |  |  | — |  |  | 2,268 |

| 21 |

Table of Contents
Information for Alliant Energy’s and IPL’s fair value measurements using significant unobservable inputs (Level 3 inputs) was as follows (in millions). Such amounts for WPL were not material.

Alliant Energy | Commodity Contract Derivative |  |
| Assets and (Liabilities), net |  | Deferred Proceeds
Three Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019
Beginning balance, July 1 |  | $36 |  |  |  | $13 |  |  |  | $194 |  |  |  | $215 |
Total net gains included in changes in net assets (realized/unrealized) | — |  |  | 13 |  |  | — |  |  | — |
Transfers out of Level 3 | — |  |  | (1 | ) |  | — |  |  | — |
Sales | (1 | ) |  | — |  |  | — |  |  | — |
Settlements (a) | (5 | ) |  | (3 | ) |  | 7 |  |  | 22 |
Ending balance, September 30 |  | $30 |  |  |  | $22 |  |  |  | $201 |  |  |  | $237 |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 |  | ($1 | ) |  |  | $13 |  |  |  | $— |  |  |  | $— |

Alliant Energy | Commodity Contract Derivative |  |
| Assets and (Liabilities), net |  | Deferred Proceeds
Nine Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019
Beginning balance, January 1 |  | $21 |  |  |  | $12 |  |  |  | $188 |  |  |  | $119 |
Total net gains included in changes in net assets (realized/unrealized) | 8 |  |  | 7 |  |  | — |  |  | — |
Transfers out of Level 3 | — |  |  | 3 |  |  | — |  |  | — |
Purchases | 14 |  |  | 14 |  |  | — |  |  | — |
Sales | (1 | ) |  | — |  |  | — |  |  | — |
Settlements (a) | (12 | ) |  | (14 | ) |  | 13 |  |  | 118 |
Ending balance, September 30 |  | $30 |  |  |  | $22 |  |  |  | $201 |  |  |  | $237 |
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 |  | $8 |  |  |  | $10 |  |  |  | $— |  |  |  | $— |

IPL | Commodity Contract Derivative |  |
| Assets and (Liabilities), net |  | Deferred Proceeds
Three Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019
Beginning balance, July 1 |  | $32 |  |  |  | $9 |  |  |  | $194 |  |  |  | $215 |
Total net gains (losses) included in changes in net assets (realized/unrealized) | (1 | ) |  | 12 |  |  | — |  |  | — |
Transfers out of Level 3 | — |  |  | (1 | ) |  | — |  |  | — |
Sales | (1 | ) |  | — |  |  | — |  |  | — |
Settlements (a) | (4 | ) |  | (2 | ) |  | 7 |  |  | 22 |
Ending balance, September 30 |  | $26 |  |  |  | $18 |  |  |  | $201 |  |  |  | $237 |
The amount of total net gains (losses) for the period included in changes in net assets attributable to the change in unrealized gains (losses) relating to assets and liabilities held at September 30 |  | ($1 | ) |  |  | $12 |  |  |  | $— |  |  |  | $— |

IPL | Commodity Contract Derivative |  |
| Assets and (Liabilities), net |  | Deferred Proceeds
Nine Months Ended September 30 | 2020 |  | 2019 |  | 2020 |  | 2019
Beginning balance, January 1 |  | $18 |  |  |  | $9 |  |  |  | $188 |  |  |  | $119 |
Total net gains included in changes in net assets (realized/unrealized) | 7 |  |  | 9 |  |  | — |  |  | — |
Transfers out of Level 3 | — |  |  | 2 |  |  | — |  |  | — |
Purchases | 11 |  |  | 9 |  |  | — |  |  | — |
Sales | (1 | ) |  | — |  |  | — |  |  | — |
Settlements (a) | (9 | ) |  | (11 | ) |  | 13 |  |  | 118 |
Ending balance, September 30 |  | $26 |  |  |  | $18 |  |  |  | $201 |  |  |  | $237 |
The amount of total net gains for the period included in changes in net assets attributable to the change in unrealized gains relating to assets and liabilities held at September 30 |  | $7 |  |  |  | $10 |  |  |  | $— |  |  |  | $— |

(a) | Settlements related to deferred proceeds are due to the change in the carrying amount of receivables sold less the allowance for doubtful accounts associated with the receivables sold and cash amounts received from the receivables sold.

| 22 |

Table of Contents
Commodity Contracts - The fair value of FTR and natural gas commodity contracts categorized as Level 3 was recognized as net derivative assets as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
| Excluding FTRs |  | FTRs |  | Excluding FTRs |  | FTRs |  | Excluding FTRs |  | FTRs
September 30, 2020 |  | $18 |  |  |  | $12 |  |  |  | $17 |  |  |  | $9 |  |  |  | $1 |  |  |  | $3 |
December 31, 2019 | 15 |  |  | 7 |  |  | 14 |  |  | 5 |  |  | 1 |  |  | 2 |

NOTE 13. COMMITMENTS AND CONTINGENCIES
NOTE 13(a) Capital Purchase Commitments - Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects. WPL’s projects include the expansion of solar and wind generation and its gas distribution system in Western Wisconsin. At September 30, 2020, Alliant Energy’s and WPL’s minimum future commitments for these projects were $21 million and $18 million, respectively.
NOTE 13(b) Other Purchase Commitments - Various commodity supply, transportation and storage contracts help meet obligations to provide electricity and natural gas to utility customers. In addition, there are various purchase commitments associated with other goods and services. At September 30, 2020, related minimum future commitments were as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
Natural gas |  | $983 |  |  |  | $508 |  |  |  | $475 |
Coal (a) | 125 |  |  | 70 |  |  | 55 |
Other (b) | 111 |  |  | 49 |  |  | 31 |
|  | $1,219 |  |  |  | $627 |  |  |  | $561 |

(a) | Corporate Services has historically entered into system-wide coal contracts on behalf of IPL and WPL that include minimum future commitments. Such commitments were assigned to IPL and WPL based on information available as of September 30, 2020 regarding expected future usage, which is subject to change.

(b) | Includes individual commitments incurred during the normal course of business that exceeded $1 million at September 30, 2020.

Refer to Note 2 for discussion of an amendment to shorten the term of the DAEC PPA, which resulted in IPL making a buyout payment in September 2020.
NOTE 13(c) Guarantees and Indemnifications -
Whiting Petroleum - Whiting Petroleum is an independent oil and gas company. In 2004, Alliant Energy sold its remaining interest in Whiting Petroleum. Alliant Energy Resources, LLC, as the successor to a predecessor entity that owned Whiting Petroleum, and a wholly-owned subsidiary of AEF, continues to guarantee the partnership obligations of an affiliate of Whiting Petroleum under multiple general partnership agreements in the oil and gas industry. The guarantees do not include a maximum limit. Based on information made available to Alliant Energy by Whiting Petroleum, the Whiting Petroleum affiliate holds an approximate 6% share in the partnerships, and currently known obligations include costs associated with the future abandonment of certain facilities owned by the partnerships. The general partnerships were formed under California law, and Alliant Energy Resources, LLC may need to perform under the guarantees if the affiliate of Whiting Petroleum is unable to meet its partnership obligations.
As of September 30, 2020, the currently known partnership obligations for the abandonment obligations are estimated at $68 million, which represents Alliant Energy’s currently estimated maximum exposure under the guarantees. Alliant Energy estimates its expected loss to be a portion of the $68 million of known partnership abandonment obligations of the Whiting Petroleum affiliate and the other partners. Alliant Energy is not aware of any material liabilities related to these guarantees that it is probable that it will be obligated to pay; however, the new credit loss accounting standard adopted on January 1, 2020 requires recognition of a liability for expected credit losses related to the contingent obligations that are in the scope of these guarantees. With the adoption of this standard, Alliant Energy recorded a pre-tax $12 million cumulative effect adjustment to decrease the opening balance of retained earnings as of January 1, 2020.
Whiting Petroleum’s creditworthiness deteriorated in the first quarter of 2020, likely from significantly depressed oil and gas prices and general market conditions, and as a result, the credit loss liability was increased to $20 million in the first quarter of 2020. In April 2020, Whiting Petroleum filed for bankruptcy, and in September 2020, Whiting Petroleum completed its reorganization and emerged from bankruptcy. As a result of Whiting Petroleum’s completed bankruptcy proceedings, as well as additional information regarding the guarantees obtained from the bankruptcy proceedings, the credit loss liability was decreased to $5 million in the third quarter of 2020. The credit loss liability is recorded in “Other liabilities” on Alliant Energy’s balance sheet as of September 30, 2020. For the three and nine months ended September 30, 2020, the pre-tax credit loss adjustments of $15 million and $7 million, respectively, were recorded as reductions in Alliant Energy’s “Other operation and maintenance” expenses.

| 23 |

Table of Contents
Non-utility Wind Farm in Oklahoma - In 2017, a wholly-owned subsidiary of AEF acquired a cash equity ownership interest in a non-utility wind farm located in Oklahoma. The wind farm provides electricity to a third-party under a long-term PPA. Alliant Energy provided a parent guarantee of its subsidiary’s indemnification obligations under the related operating agreement and PPA. Alliant Energy’s obligations under the operating agreement were $74 million as of September 30, 2020 and will reduce annually until expiring in July 2047. Alliant Energy’s obligations under the PPA are subject to a maximum limit of $17 million and expire in December 2031, subject to potential extension. Alliant Energy is not aware of any material liabilities related to this guarantee that it is probable that it will be obligated to pay and therefore has not recognized any material liabilities related to this guarantee as of September 30, 2020 and December 31, 2019.
IPL’s Minnesota Electric Distribution Assets - IPL provided indemnifications associated with the 2015 sale of its Minnesota electric distribution assets for losses resulting from potential breach of IPL’s representations, warranties and obligations under the sale agreement. IPL has not recorded any material liabilities related to these indemnifications as of September 30, 2020 and December 31, 2019. The general terms of the indemnifications provided by IPL included a maximum limit of $17 million and expired in October 2020.
NOTE 13(d) Environmental Matters -
Manufactured Gas Plant (MGP) Sites - IPL and WPL have current or previous ownership interests in various sites that are previously associated with the production of gas for which IPL and WPL have, or may have in the future, liability for investigation, remediation and monitoring costs. IPL and WPL are working pursuant to the requirements of various federal and state agencies to investigate, mitigate, prevent and remediate, where necessary, the environmental impacts to property, including natural resources, at and around these former MGP sites in order to protect public health and the environment. At September 30, 2020, estimated future costs expected to be incurred for the investigation, remediation and monitoring of the MGP sites, as well as environmental liabilities recorded on the balance sheets for these sites, which are not discounted, were as follows (in millions). At September 30, 2020, such amounts for WPL were not material.

| Alliant Energy |  | IPL
Range of estimated future costs |  | $12 |  | - | $29 |  |  | $9 |  | - | $24
Current and non-current environmental liabilities | 16 |  | 13

IPL Consent Decree - In 2015, the U.S. District Court for the Northern District of Iowa approved a Consent Decree that IPL entered into with the EPA, the Sierra Club, the State of Iowa and Linn County in Iowa, thereby resolving potential Clean Air Act issues associated with emissions from IPL’s coal-fired generating facilities in Iowa. IPL has completed various requirements under the Consent Decree. IPL’s remaining requirements include fuel switching or retiring Burlington by December 31, 2021 and Prairie Creek Units 1 and 3 by December 31, 2025. Alliant Energy and IPL currently expect to recover material costs incurred by IPL related to compliance with the terms of the Consent Decree from IPL’s electric customers.
Other Environmental Contingencies - In addition to the environmental liabilities discussed above, various environmental rules are monitored that may have a significant impact on future operations. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Given uncertainties regarding the outcome, timing and compliance plans for these environmental matters, the complete financial impact of each of these rules is not able to be determined; however, future capital investments and/or modifications to EGUs to comply with certain of these rules could be significant. Specific current, proposed or potential environmental matters include, among others: Effluent Limitation Guidelines, Coal Combustion Residuals Rule, and various legislation and EPA regulations to monitor and regulate the emission of greenhouse gases, including the Clean Air Act.
NOTE 13(e) Collective Bargaining Agreements - In August 2020, IPL’s collective bargaining agreement with International Brotherhood of Electrical Workers Local 204 (Cedar Rapids) expired and a new agreement was reached, which expires August 31, 2024.
NOTE 13(f) MISO Transmission Owner Return on Equity Complaints - A group of MISO cooperative and municipal utilities previously filed complaints with FERC requesting a reduction to the base return on equity used by MISO transmission owners, including ITC Midwest LLC and ATC. The first complaint covered the period from November 12, 2013 through February 11, 2015. In 2017, IPL and WPL received refunds related to the first complaint period, which were subsequently refunded to their retail and wholesale customers. The second complaint covered the period from February 12, 2015 through May 11, 2016. In November 2019, FERC issued an order on the previously filed complaints and reduced the base return on equity used by the MISO transmission owners to 9.88% effective for the first complaint period and subsequent to September 28, 2016. The November 2019 FERC order also dismissed the second complaint; therefore, FERC did not direct refunds to be made for that complaint. In May 2020, FERC issued an order in response to various rehearing requests and increased the base return on equity used by the MISO transmission owners from 9.88% to 10.02% for the first complaint period and subsequent to September 28, 2016, which reduces the refunds originally anticipated to be received by IPL and WPL as a result of FERC’s November 2019 order.
For the nine months ended September 30, 2020, IPL and WPL received $15 million and $5 million, respectively, in refunds related to the FERC orders. In October 2020, FERC extended the time to complete additional refunds to September 2021.

| 24 |

Table of Contents
IPL currently expects that all refunds will be returned to its retail electric customers after refund amounts and timing are known and a refund plan is approved by the IUB. WPL proposed to retain the refunds as part of WPL’s application with the PSCW to maintain its current retail electric base rates through the end of 2021. WPL currently expects that any refunds not utilized to maintain base rates would be returned to its customers in WPL’s next retail electric rate review proceeding. Any further changes in FERC’s decisions may have an impact on Alliant Energy’s share of ATC’s future earnings and customer costs.
NOTE 14. SEGMENTS OF BUSINESS
Certain financial information relating to Alliant Energy’s, IPL’s and WPL’s business segments is as follows. Intersegment revenues were not material to their respective operations.

Alliant Energy |  |  |  |  |  |  |  |  | ATC Holdings, |  | Alliant
| Utility |  | Non-Utility, |  | Energy
| Electric |  | Gas |  | Other |  | Total |  | Parent and Other |  | Consolidated
| (in millions)
Three Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues |  | $852 |  |  |  | $42 |  |  |  | $10 |  |  |  | $904 |  |  |  | $16 |  |  |  | $920 |
Operating income (loss) | 251 |  |  | (1 | ) |  | 1 |  |  | 251 |  |  | 21 |  |  | 272 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 221 |  |  | 25 |  |  | 246 |
Three Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |
Revenues |  | $916 |  |  |  | $42 |  |  |  | $11 |  |  |  | $969 |  |  |  | $21 |  |  |  | $990 |
Operating income (loss) | 284 |  |  | (5 | ) |  | 3 |  |  | 282 |  |  | 8 |  |  | 290 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 217 |  |  | 9 |  |  | 226 |

Alliant Energy |  |  |  |  |  |  |  |  | ATC Holdings, |  | Alliant
| Utility |  | Non-Utility, |  | Energy
| Electric |  | Gas |  | Other |  | Total |  | Parent and Other |  | Consolidated
| (in millions)
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |  |  |  |  |
Revenues |  | $2,257 |  |  |  | $253 |  |  |  | $32 |  |  |  | $2,542 |  |  |  | $57 |  |  |  | $2,599 |
Operating income | 549 |  |  | 48 |  |  | 5 |  |  | 602 |  |  | 26 |  |  | 628 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 510 |  |  | 40 |  |  | 550 |
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |  |  |  |  |
Revenues |  | $2,350 |  |  |  | $323 |  |  |  | $33 |  |  |  | $2,706 |  |  |  | $62 |  |  |  | $2,768 |
Operating income | 543 |  |  | 47 |  |  | 5 |  |  | 595 |  |  | 22 |  |  | 617 |
Net income attributable to Alliant Energy common shareowners |  |  |  |  |  |  | 422 |  |  | 24 |  |  | 446 |

IPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues |  | $519 |  |  |  | $24 |  |  |  | $10 |  |  |  | $553 |
Operating income | 159 |  |  | 1 |  |  | 2 |  |  | 162 |
Net income available for common stock |  |  |  |  |  |  | 148 |
Three Months Ended September 30, 2019 |  |  |  |  |  |  |
Revenues |  | $561 |  |  |  | $25 |  |  |  | $11 |  |  |  | $597 |
Operating income (loss) | 175 |  |  | (4 | ) |  | 3 |  |  | 174 |
Net income available for common stock |  |  |  |  |  |  | 141 |
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues |  | $1,332 |  |  |  | $141 |  |  |  | $31 |  |  |  | $1,504 |
Operating income | 308 |  |  | 34 |  |  | 5 |  |  | 347 |
Net income available for common stock |  |  |  |  |  |  | 290 |
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |
Revenues |  | $1,373 |  |  |  | $188 |  |  |  | $32 |  |  |  | $1,593 |
Operating income | 291 |  |  | 26 |  |  | 5 |  |  | 322 |
Net income available for common stock |  |  |  |  |  |  | 239 |

| 25 |

Table of Contents

WPL | Electric |  | Gas |  | Other |  | Total
| (in millions)
Three Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues |  | $333 |  |  |  | $18 |  |  |  | $— |  |  |  | $351 |
Operating income (loss) | 92 |  |  | (2 | ) |  | (1 | ) |  | 89 |
Net income |  |  |  |  |  |  | 73 |
Three Months Ended September 30, 2019 |  |  |  |  |  |  |
Revenues |  | $355 |  |  |  | $17 |  |  |  | $— |  |  |  | $372 |
Operating income (loss) | 109 |  |  | (1 | ) |  | — |  |  | 108 |
Net income |  |  |  |  |  |  | 76 |
Nine Months Ended September 30, 2020 |  |  |  |  |  |  |
Revenues |  | $925 |  |  |  | $112 |  |  |  | $1 |  |  |  | $1,038 |
Operating income | 241 |  |  | 14 |  |  | — |  |  | 255 |
Net income |  |  |  |  |  |  | 220 |
Nine Months Ended September 30, 2019 |  |  |  |  |  |  |
Revenues |  | $977 |  |  |  | $135 |  |  |  | $1 |  |  |  | $1,113 |
Operating income | 252 |  |  | 21 |  |  | — |  |  | 273 |
Net income |  |  |  |  |  |  | 183 |

NOTE 15. RELATED PARTIES
Service Agreements - Pursuant to service agreements, IPL and WPL receive various administrative and general services from an affiliate, Corporate Services. These services are billed to IPL and WPL at cost based on expenses incurred by Corporate Services for the benefit of IPL and WPL, respectively. These costs consisted primarily of employee compensation and benefits, fees associated with various professional services, depreciation and amortization of property, plant and equipment, and a return on net assets. Corporate Services also acts as agent on behalf of IPL and WPL pursuant to the service agreements. As agent, Corporate Services enters into energy, capacity, ancillary services, and transmission sale and purchase transactions within MISO. Corporate Services assigns such sales and purchases among IPL and WPL based on statements received from MISO. The amounts billed for services provided, sales credited and purchases for the three and nine months ended September 30 were as follows (in millions):

| IPL |  | WPL
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Corporate Services billings |  | $53 |  |  |  | $47 |  |  |  | $134 |  |  |  | $137 |  |  |  | $41 |  |  |  | $36 |  |  |  | $108 |  |  |  | $104 |
Sales credited | 10 |  |  | 23 |  |  | 35 |  |  | 50 |  |  | — |  |  | 2 |  |  | 4 |  |  | 6 |
Purchases billed | 110 |  |  | 93 |  |  | 248 |  |  | 251 |  |  | 39 |  |  | 32 |  |  | 79 |  |  | 91 |

Net intercompany payables to Corporate Services were as follows (in millions):

| IPL |  | WPL
| September 30, 2020 |  | December 31, 2019 |  | September 30, 2020 |  | December 31, 2019
Net payables to Corporate Services | $119 |  | $112 |  | $77 |  | $85

ATC - Pursuant to various agreements, WPL receives a range of transmission services from ATC. WPL provides operation, maintenance, and construction services to ATC. WPL and ATC also bill each other for use of shared facilities owned by each party. The related amounts billed between the parties for the three and nine months ended September 30 were as follows (in millions):

| Three Months |  | Nine Months
| 2020 |  | 2019 |  | 2020 |  | 2019
ATC billings to WPL |  | $27 |  |  |  | $28 |  |  |  | $80 |  |  |  | $82 |
WPL billings to ATC | 2 |  |  | 3 |  |  | 8 |  |  | 10 |

WPL owed ATC net amounts of $9 million as of September 30, 2020 and $9 million as of December 31, 2019. In the second quarter of 2020, WPL received $46 million from ATC related to construction deposits WPL previously provided ATC for transmission network upgrades for West Riverside, which is substantially recorded in “Other” in Alliant Energy’s and WPL’s cash flows from investing activities.

| 26 |

Table of Contents
ITEM 2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
This MDA includes information relating to Alliant Energy, and IPL and WPL (collectively, the Utilities), as well as ATC Holdings, AEF and Corporate Services. Where appropriate, information relating to a specific entity has been segregated and labeled as such. The following discussion and analysis should be read in conjunction with the Financial Statements and the Notes included in this report, as well as the financial statements, notes and MDA included in the 2019 Form 10-K. Unless otherwise noted, all “per share” references in MDA refer to earnings per diluted share.
2020 HIGHLIGHTS
Key highlights since the filing of the 2019 Form 10-K include the following:
COVID-19:
The outbreak of COVID-19 has become a global pandemic and Alliant Energy’s service territories are not immune to the challenges presented by COVID-19. Despite these challenges, Alliant Energy, IPL and WPL continue to focus on providing the critical, reliable service their customers depend on, while emphasizing the health and welfare of their employees, customers and communities. Alliant Energy, IPL and WPL have not experienced significant impacts on their overall business operations, financial condition, results of operations or cash flows for the three and nine months ended September 30, 2020; however, the degree to which the COVID-19 pandemic may impact such items in the future is currently unknown and will depend on future developments of the pandemic as well as possible additional actions by government and regulatory authorities. Alliant Energy has mitigated the impact of sales declines from COVID-19 by accelerating planned cost transformation activities. Actual and potential impacts from COVID-19 include, but are not limited to, the following:
Operational and Supply Chain Impacts - Alliant Energy has modified certain business practices to help ensure the health and safety of its employees, contractors, customers and vendors consistent with orders and best practices issued by government and regulatory authorities. For example, Alliant Energy implemented its business continuity and pandemic plans for critical items and services, including travel restrictions, physical distancing, working-from-home protocols, and rescheduling of planned EGU outages. Alliant Energy also temporarily suspended service disconnects, waived late payment fees for its customers, and modified reconnect service procedures to ensure continuity of service for customers unable to pay their bills and consistency with regulatory orders.
While Alliant Energy has not experienced any significant issues to-date, it continues to monitor potential disruptions or constraints in materials and supplies from key suppliers. In addition, Alliant Energy’s construction projects are currently progressing as planned with added safety protocols, and while it continues to monitor its supply chain, there have been no immediate disruptions. Alliant Energy’s wind farms under construction during the pandemic were placed in service as previously planned to meet the timing requirements to qualify for the maximum renewable tax credits. In addition, Alliant Energy does not currently expect any material changes to its construction and acquisition expenditures plans disclosed in “Liquidity and Capital Resources” resulting from COVID-19.
Alliant Energy has not experienced, and currently does not expect, an interruption in its ability to provide electric and natural gas services to its customers. Alliant Energy currently expects to incur incremental direct expenses related to certain of these operational changes and does not expect them to have a material impact on its results of operations.
Customer Impacts - COVID-19 has resulted in various travel restrictions and closures of commercial spaces and industrial facilities in Alliant Energy’s service territories. While the total expected impact of COVID-19 on future sales is currently unknown, Alliant Energy has experienced higher electric residential sales and lower electric commercial and industrial sales since the outset of the pandemic. For the nine months ended September 30, 2020 compared to the same period in 2019, Alliant Energy’s retail electric residential temperature-normalized sales increased 3%, and its retail electric commercial and industrial temperature-normalized sales decreased 4% in aggregate. While sales to retail electric commercial and industrial customers have largely recovered to pre-COVID-19 levels in the third quarter of 2020, given the continued uncertainty of COVID-19 impacts on sales, Alliant Energy currently expects a slight reduction in temperature-normalized retail sales in 2020 compared to 2019. From a sensitivity perspective, Alliant Energy currently estimates that an annual 1% increase/decrease in sales for each customer type would result in corresponding annual impacts of $0.02 EPS for its retail electric residential customers, $0.01 EPS for its retail electric commercial customers and $0.01 EPS for its retail electric industrial customers.
Liquidity and Capital Resources Impacts - In response to the uncertainty of the impacts of COVID-19, Alliant Energy enhanced its liquidity position in the first quarter of 2020 by settling $222 million under the equity forward sale agreements and AEF accelerating the refinancing of its $300 million term-loan credit agreement that would have been due in April 2020. In March 2020 and April 2020, Alliant Energy and WPL borrowed under the single credit facility for a portion of their cash needs to obtain more favorable interest rates than available in the commercial paper market. This single credit facility also allows borrowing capacity to shift among Alliant Energy (at the parent company level), IPL and WPL as needed. I n April 2020, WPL issued $350 million of debentures due 2050, and in June 2020, IPL issued $400 million of senior debentures due 2030. In June 2020, IPL and WPL retired $200 million and $150 million of long-term debt, respectively, and there are no other material long-term debt maturities in 2020 and 2021. In addition, IPL maintains a sales of accounts receivable program as an alternative financing source; however, if customer arrears were to exceed certain levels, IPL’s access to the program may be restricted.

| 27 |

Table of Contents
Alliant Energy, IPL and WPL currently expect to maintain compliance with the financial covenants of the credit facility agreement, and Alliant Energy currently expects to maintain compliance with the financial covenants in AEF’s term loan credit agreement. In addition, Alliant Energy currently expects to have adequate liquidity to fulfill its contractual obligations, access to capital markets and continue with its planned quarterly dividend payments.
Credit Risk Impacts - Alliant Energy’s temporary suspension of service disconnects and waivers of late payment fees for its customers, as well as broad economic factors, may negatively impact its customers’ willingness and ability to pay, which could increase customer arrears and bad debts, and negatively impact Alliant Energy’s cash flows from operations. Currently, Alliant Energy does not anticipate any material credit risk related to its commodity transactions.
Regulatory Impacts - In March 2020, WPL received authorization from the PSCW to defer certain incremental costs incurred resulting from COVID-19, including bad debt expenses and foregone revenues from late payment fees and deposits. In June 2020, IPL filed a proposal with the IUB for utilization of a regulatory asset account to track increased expenses and other financial impacts incurred after March 1, 2020 resulting from COVID-19. The recovery of any authorized deferrals will be addressed in future regulatory proceedings. For the three and nine months ended September 30, 2020, such recorded amounts were not material.
Legislative Impacts - In March 2020, the Coronavirus Aid, Relief, and Economic Security Act (CARES Act) was enacted. The most significant provision of the CARES Act for Alliant Energy relates to an acceleration of refunds of existing alternative minimum tax credits to improve liquidity. In July 2020, Alliant Energy received $11 million of credits that otherwise would have been received in 2021 and 2022. In addition, Alliant Energy has deferred certain 2020 payroll taxes to 2021 and 2022. The CARES Act also provides additional funding to the Low Income Home Energy Assistance Program, which assists certain of Alliant Energy’s customers with managing their energy costs, as well as financial support for certain of Alliant Energy’s residential, small business and non-profit customers.
August 2020 Derecho Windstorm:
In August 2020, a derecho windstorm caused considerable damage to IPL’s electric distribution system in its service territory, and over 250,000 of its customers lost power. IPL completed its initial restoration efforts in August 2020 and expects permanent repairs to the system to continue throughout 2020. Refer to Note 2 for further discussion, including IPL’s current estimate and requested regulatory treatment of certain incremental costs and benefits incurred resulting from the windstorm.
Rate Matters:

• | Final retail electric rates for IPL’s 2020 Forward-looking Test Period rate review were effective February 26, 2020. Effective with the implementation of final rates, IPL started to recover a return of and return on its new wind generation placed in service in 2019 and 2020 through the renewable energy rider. IPL currently expects to file a subsequent proceeding with the IUB in the first half of 2021 for its 2020 Forward-looking Test Period retail electric and gas rate reviews, which will compare actual revenues and costs to those initially forecasted by IPL. IPL currently does not expect any rate adjustments from the subsequent proceeding.

• | In August 2020, the PSCW issued an oral decision authorizing WPL to maintain its current retail electric and gas base rates, authorized return on common equity, regulatory capital structure and earnings sharing mechanism through the end of 2021. WPL will utilize anticipated fuel-related cost savings in 2021 to offset the revenue requirement impacts of the Kossuth wind farm, which was placed in service in October 2020. In addition, WPL will utilize excess deferred tax benefits to partially offset the revenue requirement of the expansion of its gas distribution system in Western Wisconsin, which is expected to be placed in service in late 2020. A written order from the PSCW is currently expected in the fourth quarter of 2020.

• | In the second quarter of 2020, pursuant to a June 2020 IUB order, IPL issued $42 million of credits to its retail electric customers through its transmission cost rider for amounts previously collected in rates.

• | In September 2020, pursuant to an August 2020 PSCW order, WPL refunded $12 million of 2019 fuel-related cost over-collections to its retail electric customers.

• | In September 2020, IPL made a buyout payment of $110 million in exchange for shortening the term of its DAEC PPA by 5 years. Pursuant to IUB and FERC orders, the buyout payment will be recovered from IPL’s retail and wholesale customers beginning in the fourth quarter of 2020 and through the end of 2025.

• | Beginning in the third quarter of 2020, IPL began providing retail electric billing credits that will continue through June 2021, which in aggregate include $27 million of excess deferred tax benefits and $8 million from a partial refund of interim rates implemented in 2019.

• | WPL currently expects to file a retail electric and gas rate review with the PSCW in the second quarter of 2021 for either a single or multiple year forward-looking test period.

Customer Investments:

• | In March 2020, IPL completed the construction of the Golden Plains wind farm in Iowa (200 MW).

• | In April 2020, WPL received authorization from the PSCW to expand its gas distribution system in Western Wisconsin, which is currently expected to be completed in 2020.

• | In May 2020, WPL completed the construction of the natural gas-fired West Riverside Energy Center (730 MW).

| 28 |

Table of Contents

• | In May 2020, WPL filed a Certificate of Authority with the PSCW for approval to acquire, construct, own, and operate up to 675 MW of new solar generation in the following Wisconsin counties: Grant (200 MW in 2023), Sheboygan (150 MW in 2022), Wood (150 MW in 2022), Jefferson (75 MW in 2022), Richland (50 MW in 2022) and Rock (50 MW in 2023). The 675 MW of new solar generation would replace energy and capacity being eliminated with the planned retirement of the coal-fired Edgewater Generating Station (414 MW) by the end of 2022, which is subject to change depending on operational, regulatory, market and other factors. In addition, WPL currently expects to file a second Certificate of Authority with the PSCW in the first half of 2021 for approximately 325 MW of new solar generation. Estimated capital expenditures for these planned projects for 2020 through 2024 are included in the “Renewable projects” line in the construction and acquisition table in “Liquidity and Capital Resources.” WPL currently assumes that a portion of the construction costs will be financed by a tax equity partner, which is discussed in “IPL and WPL Solar Project Tax Equity Credits” in “Liquidity and Capital Resources.”

• | In July 2020, Alliant Energy announced updated voluntary environmental-related goals based on its clean energy strategy. By 2030, Alliant Energy expects to reduce carbon dioxide emissions by 50% and water supply by 75% from 2005 levels from its owned fossil-fueled generation. By 2040, Alliant Energy expects to eliminate all coal-fired EGUs from its generating fleet, and by 2050, seeks to achieve an aspirational goal of net-zero carbon dioxide emissions from the electricity it generates. Future updates to sustainable energy plans and attaining these goals will depend on future economic developments, evolving energy technologies and emerging trends in Alliant Energy’s service territories.

• | In September 2020, IPL completed the construction of the Richland wind farm in Iowa (130 MW).

• | In October 2020, WPL completed the construction of the Kossuth wind farm in Iowa (150 MW).

• | Alliant Energy’s cleaner energy strategy includes IPL’s planned development and acquisition of up to 400 MW of solar generation by the end of 2023 and up to 100 MW of distributed energy resources, including community solar and energy storage systems beginning in 2022. IPL currently plans to file for advance rate-making principles for the up to 400 MW of solar generation in the first half of 2021. Estimated capital expenditures for these planned projects for 2020 through 2024 are included in the “Renewable projects” line in the construction and acquisition table in “Liquidity and Capital Resources.” IPL currently assumes that a portion of the construction costs for the new solar generation will be financed by a tax equity partner, which is discussed in “IPL and WPL Solar Project Tax Equity Credits” in “Liquidity and Capital Resources.” The 400 MW of new solar generation would help replace a portion of the energy and capacity expected to be eliminated with the planned retirement of the coal-fired Lansing Generating Station (275 MW) by the end of 2022 and the expected reduction of energy and capacity resulting from the planned fuel switch of the Burlington Generating Station (212 MW) from coal to natural gas by the end of 2021. Both the Lansing Generating Station planned retirement and the planned fuel switch of the Burlington Generating Station are subject to change depending on operational, regulatory, market and other factors.

Financings and Common Stock Dividends:

• | In March 2020, Alliant Energy settled $222 million under the equity forward sale agreements by delivering 4,275,127 shares of newly issued Alliant Energy common stock at a weighted average forward sale price of $51.98 per share.

• | In March 2020, AEF entered into a $300 million variable rate (1% as of September 30, 2020) term loan credit agreement (with Alliant Energy as guarantor), which expires in March 2022, and used the borrowings under this agreement to retire its $300 million variable rate term loan credit agreement that would have expired in April 2020.

• | In April 2020, WPL issued $350 million of 3.65% debentures due 2050. The net proceeds from the issuance were used by WPL to reduce borrowings under the single credit facility, which currently expires in August 2023, and for general corporate purposes. In June 2020, WPL retired its $150 million 4.6% debentures.

• | In June 2020, IPL issued $400 million of 2.3% senior debentures due 2030. The net proceeds from the issuance were used by IPL to retire its $200 million 3.65% senior debentures that would have matured in September 2020 and for general corporate purposes.

• | Refer to “Results of Operations” for discussion of expected issuances of common stock dividends and long-term debt in 2021.

RESULTS OF OPERATIONS
Results of operations include financial information prepared in accordance with GAAP as well as utility electric margins and utility gas margins, which are not measures of financial performance under GAAP. Utility electric margins are defined as electric revenues less electric production fuel, purchased power and electric transmission service expenses. Utility gas margins are defined as gas revenues less cost of gas sold. Utility electric margins and utility gas margins are non-GAAP financial measures because they exclude other utility and non-utility revenues, other operation and maintenance expenses, depreciation and amortization expenses, and taxes other than income tax expense.
Management believes that utility electric and gas margins provide a meaningful basis for evaluating and managing utility operations since electric production fuel, purchased power and electric transmission service expenses and cost of gas sold are generally passed through to customers, and therefore, result in changes to electric and gas revenues that are comparable to changes in such expenses. The presentation of utility electric and gas margins herein is intended to provide supplemental information for investors regarding operating performance. These utility electric and gas margins may not be comparable to how other entities define utility electric and gas margin. Furthermore, these measures are not intended to replace operating income as determined in accordance with GAAP as an indicator of operating performance.

| 29 |

Table of Contents
Additionally, the table below includes EPS for Utilities and Corporate Services, ATC Holdings, and Non-utility and Parent, which are non-GAAP financial measures. Alliant Energy believes these non-GAAP financial measures are useful to investors because they facilitate an understanding of segment performance and trends, and provide additional information about Alliant Energy’s operations on a basis consistent with the measures that management uses to manage its operations and evaluate its performance.
Financial Results Overview - Alliant Energy’s net income and EPS attributable to Alliant Energy common shareowners for the three months ended September 30 were as follows (dollars in millions, except per share amounts):

| 2020 |  | 2019
| Income |  | EPS |  | Income (Loss) |  | EPS
Utilities and Corporate Services |  | $224 |  |  |  | $0.89 |  |  |  | $220 |  |  |  | $0.92 |
ATC Holdings | 8 |  |  | 0.03 |  |  | 8 |  |  | 0.03 |
Non-utility and Parent | 14 |  |  | 0.06 |  |  | (2 | ) |  | (0.01 | )
Alliant Energy Consolidated |  | $246 |  |  |  | $0.98 |  |  |  | $226 |  |  |  | $0.94 |

Alliant Energy’s Utilities and Corporate Services net income increased by $4 million for the three-month period, primarily due to higher earnings resulting from IPL’s and WPL’s increasing rate base and timing of income taxes. These items were partially offset by higher depreciation expense and lower sales due to the derecho windstorm in Iowa.
Alliant Energy’s Non-utility and Parent net income increased by $16 million for the three-month period primarily due to an adjustment to the credit loss liability related to legacy guarantees associated with an affiliate of Whiting Petroleum and timing of income taxes.
For the three and nine months ended September 30, operating income and a reconciliation of utility electric and gas margins to the most directly comparable GAAP measure, operating income, was as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
Three Months | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Operating income |  | $272 |  |  |  | $290 |  |  |  | $162 |  |  |  | $174 |  |  |  | $89 |  |  |  | $108 |
Electric utility revenues |  | $852 |  |  |  | $916 |  |  |  | $519 |  |  |  | $561 |  |  |  | $333 |  |  |  | $355 |
Electric production fuel and purchased power expenses | (179 | ) |  | (219 | ) |  | (102 | ) |  | (127 | ) |  | (78 | ) |  | (92 | )
Electric transmission service expense | (132 | ) |  | (127 | ) |  | (93 | ) |  | (92 | ) |  | (39 | ) |  | (36 | )
Utility Electric Margin (non-GAAP) | 541 |  |  | 570 |  |  | 324 |  |  | 342 |  |  | 216 |  |  | 227 |
Gas utility revenues | 42 |  |  | 42 |  |  | 24 |  |  | 25 |  |  | 18 |  |  | 17 |
Cost of gas sold | (11 | ) |  | (9 | ) |  | (6 | ) |  | (6 | ) |  | (4 | ) |  | (3 | )
Utility Gas Margin (non-GAAP) | 31 |  |  | 33 |  |  | 18 |  |  | 19 |  |  | 14 |  |  | 14 |
Other utility revenues | 10 |  |  | 11 |  |  | 10 |  |  | 11 |  |  | — |  |  | — |
Non-utility revenues | 16 |  |  | 21 |  |  | — |  |  | — |  |  | — |  |  | — |
Other operation and maintenance expenses | (143 | ) |  | (174 | ) |  | (85 | ) |  | (100 | ) |  | (65 | ) |  | (62 | )
Depreciation and amortization expenses | (156 | ) |  | (144 | ) |  | (89 | ) |  | (84 | ) |  | (65 | ) |  | (59 | )
Taxes other than income tax expense | (27 | ) |  | (27 | ) |  | (16 | ) |  | (14 | ) |  | (11 | ) |  | (12 | )
Operating income |  | $272 |  |  |  | $290 |  |  |  | $162 |  |  |  | $174 |  |  |  | $89 |  |  |  | $108 |

| Alliant Energy |  | IPL |  | WPL
Nine Months | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Operating income |  | $628 |  |  |  | $617 |  |  |  | $347 |  |  |  | $322 |  |  |  | $255 |  |  |  | $273 |
Electric utility revenues |  | $2,257 |  |  |  | $2,350 |  |  |  | $1,332 |  |  |  | $1,373 |  |  |  | $925 |  |  |  | $977 |
Electric production fuel and purchased power expenses | (527 | ) |  | (602 | ) |  | (304 | ) |  | (339 | ) |  | (223 | ) |  | (263 | )
Electric transmission service expense | (326 | ) |  | (363 | ) |  | (212 | ) |  | (257 | ) |  | (114 | ) |  | (106 | )
Utility Electric Margin (non-GAAP) | 1,404 |  |  | 1,385 |  |  | 816 |  |  | 777 |  |  | 588 |  |  | 608 |
Gas utility revenues | 253 |  |  | 323 |  |  | 141 |  |  | 188 |  |  | 112 |  |  | 135 |
Cost of gas sold | (117 | ) |  | (151 | ) |  | (63 | ) |  | (80 | ) |  | (53 | ) |  | (71 | )
Utility Gas Margin (non-GAAP) | 136 |  |  | 172 |  |  | 78 |  |  | 108 |  |  | 59 |  |  | 64 |
Other utility revenues | 32 |  |  | 33 |  |  | 31 |  |  | 32 |  |  | 1 |  |  | 1 |
Non-utility revenues | 57 |  |  | 62 |  |  | — |  |  | — |  |  | — |  |  | — |
Other operation and maintenance expenses | (465 | ) |  | (527 | ) |  | (269 | ) |  | (306 | ) |  | (172 | ) |  | (188 | )
Depreciation and amortization expenses | (454 | ) |  | (424 | ) |  | (264 | ) |  | (243 | ) |  | (186 | ) |  | (177 | )
Taxes other than income tax expense | (82 | ) |  | (84 | ) |  | (45 | ) |  | (46 | ) |  | (35 | ) |  | (35 | )
Operating income |  | $628 |  |  |  | $617 |  |  |  | $347 |  |  |  | $322 |  |  |  | $255 |  |  |  | $273 |

| 30 |

Table of Contents
Operating Income Variances - Variances between periods in operating income for the three and nine months ended September 30, 2020 compared to the same periods in 2019 were as follows (in millions):

| Three Months |  | Nine Months
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Total higher (lower) utility electric margin variance (Refer to details below) |  | ($29 | ) |  |  | ($18 | ) |  |  | ($11 | ) |  |  | $19 |  |  |  | $39 |  |  |  | ($20 | )
Total lower utility gas margin variance (Refer to details below) | (2 | ) |  | (1 | ) |  | — |  |  | (36 | ) |  | (30 | ) |  | (5 | )
Total lower (higher) other operation and maintenance expenses variance (Refer to details below) | 31 |  |  | 15 |  |  | (3 | ) |  | 62 |  |  | 37 |  |  | 16 |
Higher depreciation and amortization expense primarily due to additional plant in service in 2019 and 2020, including IPL’s new wind generation and WPL’s West Riverside Energy Center | (12 | ) |  | (5 | ) |  | (6 | ) |  | (30 | ) |  | (21 | ) |  | (9 | )
Other | (6 | ) |  | (3 | ) |  | 1 |  |  | (4 | ) |  | — |  |  | — |
|  | ($18 | ) |  |  | ($12 | ) |  |  | ($19 | ) |  |  | $11 |  |  |  | $25 |  |  |  | ($18 | )

Electric and Gas Revenues and Sales Summary - Electric and gas revenues (in millions), and MWh and Dth sales (in thousands), for the three and nine months ended September 30 were as follows:

Alliant Energy | Electric |  | Gas
| Revenues |  | MWhs Sold |  | Revenues |  | Dths Sold
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Three Months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail |  | $779 |  |  |  | $827 |  |  | 6,762 |  |  | 6,868 |  |  |  | $34 |  |  |  | $33 |  |  | 3,500 |  |  | 3,144 |
Sales for resale | 54 |  |  | 72 |  |  | 1,453 |  |  | 2,003 |  |  | N/A |  |  | N/A |  |  | N/A |  |  | N/A |
Transportation/Other | 19 |  |  | 17 |  |  | 17 |  |  | 23 |  |  | 8 |  |  | 9 |  |  | 24,842 |  |  | 25,021 |
|  | $852 |  |  |  | $916 |  |  | 8,232 |  |  | 8,894 |  |  |  | $42 |  |  |  | $42 |  |  | 28,342 |  |  | 28,165 |
Nine Months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail |  | $2,049 |  |  |  | $2,109 |  |  | 18,496 |  |  | 19,035 |  |  |  | $224 |  |  |  | $287 |  |  | 32,545 |  |  | 36,560 |
Sales for resale | 162 |  |  | 190 |  |  | 4,962 |  |  | 4,835 |  |  | N/A |  |  | N/A |  |  | N/A |  |  | N/A |
Transportation/Other | 46 |  |  | 51 |  |  | 53 |  |  | 71 |  |  | 29 |  |  | 36 |  |  | 79,546 |  |  | 71,814 |
|  | $2,257 |  |  |  | $2,350 |  |  | 23,511 |  |  | 23,941 |  |  |  | $253 |  |  |  | $323 |  |  | 112,091 |  |  | 108,374 |

IPL | Electric |  | Gas
| Revenues |  | MWhs Sold |  | Revenues |  | Dths Sold
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Three Months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail |  | $480 |  |  |  | $512 |  |  | 3,743 |  |  | 3,827 |  |  |  | $19 |  |  |  | $20 |  |  | 1,873 |  |  | 1,644 |
Sales for resale | 25 |  |  | 38 |  |  | 765 |  |  | 1,414 |  |  | N/A |  |  | N/A |  |  | N/A |  |  | N/A |
Transportation/Other | 14 |  |  | 11 |  |  | 9 |  |  | 9 |  |  | 5 |  |  | 5 |  |  | 9,020 |  |  | 8,701 |
|  | $519 |  |  |  | $561 |  |  | 4,517 |  |  | 5,250 |  |  |  | $24 |  |  |  | $25 |  |  | 10,893 |  |  | 10,345 |
Nine Months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail |  | $1,227 |  |  |  | $1,248 |  |  | 10,414 |  |  | 10,706 |  |  |  | $122 |  |  |  | $166 |  |  | 16,950 |  |  | 19,010 |
Sales for resale | 75 |  |  | 95 |  |  | 3,090 |  |  | 3,241 |  |  | N/A |  |  | N/A |  |  | N/A |  |  | N/A |
Transportation/Other | 30 |  |  | 30 |  |  | 27 |  |  | 27 |  |  | 19 |  |  | 22 |  |  | 29,127 |  |  | 28,528 |
|  | $1,332 |  |  |  | $1,373 |  |  | 13,531 |  |  | 13,974 |  |  |  | $141 |  |  |  | $188 |  |  | 46,077 |  |  | 47,538 |

| 31 |

Table of Contents

WPL | Electric |  | Gas
| Revenues |  | MWhs Sold |  | Revenues |  | Dths Sold
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Three Months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail |  | $299 |  |  |  | $315 |  |  | 3,019 |  |  | 3,041 |  |  |  | $15 |  |  |  | $13 |  |  | 1,627 |  |  | 1,500 |
Sales for resale | 29 |  |  | 34 |  |  | 688 |  |  | 589 |  |  | N/A |  |  | N/A |  |  | N/A |  |  | N/A |
Transportation/Other | 5 |  |  | 6 |  |  | 8 |  |  | 14 |  |  | 3 |  |  | 4 |  |  | 15,822 |  |  | 16,320 |
|  | $333 |  |  |  | $355 |  |  | 3,715 |  |  | 3,644 |  |  |  | $18 |  |  |  | $17 |  |  | 17,449 |  |  | 17,820 |
Nine Months |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Retail |  | $822 |  |  |  | $861 |  |  | 8,082 |  |  | 8,329 |  |  |  | $102 |  |  |  | $121 |  |  | 15,595 |  |  | 17,550 |
Sales for resale | 87 |  |  | 95 |  |  | 1,872 |  |  | 1,594 |  |  | N/A |  |  | N/A |  |  | N/A |  |  | N/A |
Transportation/Other | 16 |  |  | 21 |  |  | 26 |  |  | 44 |  |  | 10 |  |  | 14 |  |  | 50,419 |  |  | 43,286 |
|  | $925 |  |  |  | $977 |  |  | 9,980 |  |  | 9,967 |  |  |  | $112 |  |  |  | $135 |  |  | 66,014 |  |  | 60,836 |

Sales Trends and Temperatures - Alliant Energy’s retail electric sales volumes decreased 2% for the three months ended September 30, 2020 compared to the same period in 2019 primarily due to the impacts from the derecho windstorm in IPL’s service territory. Alliant Energy’s retail electric and gas sales volumes decreased 3% and 11% for the nine months ended September 30, 2020 compared to the same period in 2019, respectively, primarily due to the impacts from COVID-19, the derecho windstorm, and changes in temperatures in Alliant Energy’s service territories. The nine-month decrease in sales was partially offset by an extra day of sales during the first quarter of 2020 due to leap year. For the nine months ended September 30, 2020, COVID-19 impacts on sales volumes resulted in increases for retail electric residential sales volumes and decreases for retail electric commercial and industrial sales.
Estimated increases (decreases) to electric and gas margins from the impacts of temperatures for the three and nine months ended September 30 were as follows (in millions):

| Electric Margins |  | Gas Margins
| Three Months |  | Nine Months |  | Three Months |  | Nine Months
| 2020 |  | 2019 |  | Change |  | 2020 |  | 2019 |  | Change |  | 2020 |  | 2019 |  | Change |  | 2020 |  | 2019 |  | Change
IPL |  | $3 |  |  |  | $4 |  |  |  | ($1 | ) |  |  | $2 |  |  |  | $7 |  |  |  | ($5 | ) |  |  | $— |  |  |  | $— |  |  |  | $— |  |  |  | $— |  |  |  | $4 |  |  |  | ($4 | )
WPL | 3 |  |  | 2 |  |  | 1 |  |  | 3 |  |  | 2 |  |  | 1 |  |  | — |  |  | — |  |  | — |  |  | (1 | ) |  | 2 |  |  | (3 | )
Total Alliant Energy |  | $6 |  |  |  | $6 |  |  |  | $— |  |  |  | $5 |  |  |  | $9 |  |  |  | ($4 | ) |  |  | $— |  |  |  | $— |  |  |  | $— |  |  |  | ($1 | ) |  |  | $6 |  |  |  | ($7 | )

Utility Electric Margin Variances - The following items contributed to increased (decreased) utility electric margins for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

| Three Months |  | Nine Months
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Impact of IPL’s retail electric final and interim rate increases effective February 2020 and April 2019, respectively (a) |  | $7 |  |  |  | $7 |  |  |  | $— |  |  |  | $54 |  |  |  | $54 |  |  |  | $— |
Higher revenues at IPL due to credits on customers’ bills in 2019 related to production tax credits through the fuel-related cost recovery mechanism (offset by changes in income tax) | 3 |  |  | 3 |  |  | — |  |  | 13 |  |  | 13 |  |  | — |
Higher revenues at IPL due to changes in electric tax benefit rider credits on customers’ bills (offset by changes in income tax) | — |  |  | — |  |  | — |  |  | 6 |  |  | 6 |  |  | — |
Higher WPL electric fuel-related costs, net of recoveries | (12 | ) |  | — |  |  | (12 | ) |  | (12 | ) |  | — |  |  | (12 | )
Changes in timing of collection of electric transmission service costs at WPL | (3 | ) |  | — |  |  | (3 | ) |  | (8 | ) |  | — |  |  | (8 | )
Lower revenues at IPL due to credits on customers’ bills in 2020 related to excess deferred amortization through the tax benefit rider (offset by changes in income tax) | (8 | ) |  | (8 | ) |  | — |  |  | (8 | ) |  | (8 | ) |  | — |
Lower revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense) | (5 | ) |  | (5 | ) |  | — |  |  | (4 | ) |  | (4 | ) |  | — |
Estimated changes in sales volumes caused by temperatures | — |  |  | (1 | ) |  | 1 |  |  | (4 | ) |  | (5 | ) |  | 1 |
Other (includes lower temperature-normalized sales primarily due to the derecho windstorm and COVID-19 impacts) | (11 | ) |  | (14 | ) |  | 3 |  |  | (18 | ) |  | (17 | ) |  | (1 | )
|  | ($29 | ) |  |  | ($18 | ) |  |  | ($11 | ) |  |  | $19 |  |  |  | $39 |  |  |  | ($20 | )

| 32 |

Table of Contents

(a) | IPL’s interim retail electric base rate increase was effective April 1, 2019 and final retail electric base rate increase was effective February 26, 2020. Effective with final rates, the recovery of, and return on, IPL’s new wind generation placed in service in 2019 and 2020 is provided through the renewable energy rider. Both interim and final rate increases include a reduction for anticipated production tax credits for IPL’s new wind generation. This reduction is expected to be offset by a reduction in income tax expense resulting from production tax credits recognized from this new wind generation.

Utility Gas Margin Variances - The following items contributed to increased (decreased) utility gas margins for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

| Three Months |  | Nine Months
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Lower revenues at IPL related to changes in recovery amounts for energy efficiency costs through the energy efficiency rider (mostly offset by changes in energy efficiency expense) |  | ($2 | ) |  |  | ($2 | ) |  |  | $— |  |  |  | ($29 | ) |  |  | ($29 | ) |  |  | $— |
Estimated changes in sales volumes caused by temperatures | — |  |  | — |  |  | — |  |  | (7 | ) |  | (4 | ) |  | (3 | )
Impact of IPL’s retail gas rate increase effective January 2020 | 1 |  |  | 1 |  |  | — |  |  | 8 |  |  | 8 |  |  | — |
Other (includes lower temperature-normalized sales primarily due to COVID-19 impacts) | (1 | ) |  | — |  |  | — |  |  | (8 | ) |  | (5 | ) |  | (2 | )
|  | ($2 | ) |  |  | ($1 | ) |  |  | $— |  |  |  | ($36 | ) |  |  | ($30 | ) |  |  | ($5 | )

Other Operation and Maintenance Expenses Variances - The following items contributed to (increased) decreased other operation and maintenance expenses for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

| Three Months |  | Nine Months
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Lower energy efficiency expense at IPL (primarily offset by lower gas revenues) |  | $6 |  |  |  | $6 |  |  |  | $— |  |  |  | $32 |  |  |  | $32 |  |  |  | $— |
Lower generation operation and maintenance expenses | 3 |  |  | 3 |  |  | — |  |  | 12 |  |  | 5 |  |  | 7 |
Credit loss adjustments related to guarantees for an affiliate of Whiting Petroleum (Refer to Note 13(c)) | 15 |  |  | — |  |  | — |  |  | 7 |  |  | — |  |  | — |
Other | 7 |  |  | 6 |  |  | (3 | ) |  | 11 |  |  | — |  |  | 9 |
|  | $31 |  |  |  | $15 |  |  |  | ($3 | ) |  |  | $62 |  |  |  | $37 |  |  |  | $16 |

Other Income and Deductions Variances - The following items contributed to (increased) decreased other income and deductions for the three and nine months ended September 30, 2020 compared to the same periods in 2019 as follows (in millions):

| Three Months |  | Nine Months
| Alliant Energy |  | IPL |  | WPL |  | Alliant Energy |  | IPL |  | WPL
Higher interest expense primarily due to higher average outstanding long-term debt balances |  | $— |  |  |  | ($3 | ) |  |  | ($1 | ) |  |  | ($3 | ) |  |  | ($11 | ) |  |  | ($1 | )
Lower allowance for funds used during construction primarily due to changes in construction work in progress balances related to IPL’s new wind generation and WPL’s West Riverside Energy Center and new wind generation | (9 | ) |  | (5 | ) |  | (5 | ) |  | (15 | ) |  | (13 | ) |  | (2 | )
Other (Refer to Note 4 for details of increased income from unconsolidated equity investments) | 4 |  |  | 1 |  |  | — |  |  | 15 |  |  | 2 |  |  | 1 |
|  | ($5 | ) |  |  | ($7 | ) |  |  | ($6 | ) |  |  | ($3 | ) |  |  | ($22 | ) |  |  | ($2 | )

Income Taxes - Alliant Energy’s overall effective income tax rates were (9)% and 9% for the three months ended September 30, 2020 and 2019, and (9)% and 10% for the nine months ended September 30, 2020 and 2019, respectively. The decrease in effective income tax rates is primarily due to increases in production tax credits as a result of increased wind production in 2020 and increases of amortization of excess deferred taxes primarily at WPL. WPL’s 2020 increased revenue requirements are offset by returning to customers a portion of the excess deferred income tax credits from Federal Tax Reform. Excess deferred income taxes and production tax credits are recognized based on an estimated annual effective tax rate, which contributed to a positive earnings variance during the nine months ended September 30, 2020. This positive earnings variance is expected to reverse by the end of 2020.

| 33 |

Table of Contents
Other Future Considerations - In addition to items discussed in MDA and the Notes in Item 1, the following key items could impact Alliant Energy’s, IPL’s and WPL’s future financial condition or results of operations:

• | Financing Plans - WPL and AEF each currently expect to issue up to $300 million of long-term debt by the end of 2021.

• | Common Stock Dividends - Alliant Energy announced a 6% increase in its targeted 2021 annual common stock dividend to $1.61 per share, which is equivalent to a quarterly rate of $0.4025 per share, beginning with the February 2021 dividend payment. The timing and amount of future dividends is subject to an approved dividend declaration from Alliant Energy’s Board of Directors, and is dependent upon earnings expectations, capital requirements, and general financial business conditions, among other factors.

• | Higher Earnings on Increasing Rate Base - Alliant Energy, IPL and WPL currently expect an increase in earnings in 2021 compared to 2020 due to impacts from increasing revenue requirements related to investments in the utility business, including IPL’s and WPL’s wind investments, WPL’s Western Wisconsin gas distribution system expansion, and the impacts of IPL’s DAEC PPA amendment buyout payment.

• | Depreciation and Amortization Expenses - Alliant Energy, IPL and WPL currently expect an increase in depreciation and amortization expenses in 2021 compared to 2020 due to property additions, including IPL’s and WPL’s expansion of wind generation and WPL’s natural gas-fired West Riverside Energy Center.

• | Allowance for Funds Used During Construction - Alliant Energy currently expects allowance for funds used during construction to decrease in 2021 compared to 2020 primarily due to decreased construction work in progress balances related to IPL’s and WPL’s wind generation and WPL’s West Riverside Energy Center, which were placed in service in 2020.

LIQUIDITY AND CAPITAL RESOURCES
The liquidity and capital resources summary included in the 2019 Form 10-K has not changed materially, except as described below.
COVID-19 and Derecho Windstorm Considerations - Refer to “2020 Highlights” for discussion of COVID-19 and the derecho windstorm and the current and expected impacts on Alliant Energy’s, IPL’s and WPL’s liquidity and capital resources.
Liquidity Position - At September 30, 2020, Alliant Energy had $189 million of cash and cash equivalents, $578 million ($167 million at the parent company, $250 million at IPL and $161 million at WPL) of available capacity under the single revolving credit facility and $109 million of available capacity at IPL under its sales of accounts receivable program.
Capital Structure - Capital structures at September 30, 2020 were as follows (Long-term Debt (including current maturities) (LD); Short-term Debt (SD); Common Equity (CE); IPL’s Preferred Stock (PS)):
Cash Flows - Selected information from the cash flows statements was as follows (in millions):

| Alliant Energy |  | IPL |  | WPL
| 2020 |  | 2019 |  | 2020 |  | 2019 |  | 2020 |  | 2019
Cash, cash equivalents and restricted cash, January 1 |  | $18 |  |  |  | $26 |  |  |  | $9 |  |  |  | $12 |  |  |  | $4 |  |  |  | $9 |
Cash flows from (used for): |  |  |  |  |  |  |  |  |  |  |
Operating activities | 436 |  |  | 509 |  |  | 19 |  |  | 139 |  |  | 402 |  |  | 360 |
Investing activities | (679 | ) |  | (861 | ) |  | (202 | ) |  | (484 | ) |  | (465 | ) |  | (335 | )
Financing activities | 419 |  |  | 526 |  |  | 359 |  |  | 518 |  |  | 61 |  |  | (24 | )
Net increase (decrease) | 176 |  |  | 174 |  |  | 176 |  |  | 173 |  |  | (2 | ) |  | 1 |
Cash, cash equivalents and restricted cash, September 30 |  | $194 |  |  |  | $200 |  |  |  | $185 |  |  |  | $185 |  |  |  | $2 |  |  |  | $10 |

| 34 |

Table of Contents
Operating Activities - The following items contributed to increased (decreased) operating activity cash flows for the nine months ended September 30, 2020 compared to the same period in 2019 (in millions):

| Alliant Energy |  | IPL |  | WPL
DAEC PPA amendment buyout payment in 2020 (Refer to Note 2) |  | ($110 | ) |  |  | ($110 | ) |  |  | $— |
Amounts issued to IPL’s retail electric customers in 2020 through its transmission cost rider for amounts previously collected in rates (Refer to Note 2) | (42 | ) |  | (42 | ) |  | — |
Decreased collections from IPL’s and WPL’s retail customers caused by temperature impacts on electric and gas sales | (11 | ) |  | (9 | ) |  | (2 | )
Changes in interest payments | (2 | ) |  | (15 | ) |  | 3 |
Higher collections from IPL’s retail electric and gas base rate increases | 62 |  |  | 62 |  |  | — |
Changes in levels of production fuel | 24 |  |  | (3 | ) |  | 27 |
Refunds received in 2020 related to the MISO transmission owner return on equity complaint FERC orders (Refer to Note 13(f)) | 20 |  |  | 15 |  |  | 5 |
Changes in income taxes paid/refunded | 5 |  |  | (20 | ) |  | 12 |
Other (primarily due to other changes in working capital) | (19 | ) |  | 2 |  |  | (3 | )
|  | ($73 | ) |  |  | ($120 | ) |  |  | $42 |

Investing Activities - The following items contributed to increased (decreased) investing activity cash flows for the nine months ended September 30, 2020 compared to the same period in 2019 (in millions):

| Alliant Energy |  | IPL |  | WPL
Changes in the amount of cash receipts on sold receivables |  | $62 |  |  |  | $62 |  |  |  | $— |
Refund from ATC in 2020 for construction deposits WPL previously provided to ATC for transmission network upgrades for West Riverside | 42 |  |  | — |  |  | 42 |
Lower (higher) utility construction and acquisition expenditures (a) | 69 |  |  | 231 |  |  | (162 | )
Expenditures for new acquisitions at AEF in 2019 | 13 |  |  | — |  |  | — |
Other | (4 | ) |  | (11 | ) |  | (10 | )
|  | $182 |  |  |  | $282 |  |  |  | ($130 | )

(a) | Largely due to lower expenditures for IPL’s expansion of wind generation, IPL’s advanced metering infrastructure and WPL’s West Riverside Energy Center, partially offset by higher expenditures for IPL’s and WPL’s electric and gas distribution systems (which include the derecho windstorm) and WPL’s expansion of wind generation.

Construction and Acquisition Expenditures - Construction and acquisition expenditures for 2020 through 2024 are currently anticipated as follows (in millions). Cost estimates represent Alliant Energy’s, IPL’s and WPL’s portion of construction expenditures and exclude allowance for funds used during construction and capitalized interest, if applicable. Such estimates do not include IPL’s September 2020 $110 million buyout payment related to the DAEC PPA, do not reflect any potential proceeds if neighboring utilities exercise options for a partial ownership in West Riverside, and do not reflect the assumed portion of construction costs that are expected to be financed by tax equity partners, as discussed below in “IPL and WPL Solar Project Tax Equity Credits.” Refer to “2020 Highlights” for discussion of IPL’s and WPL’s planned new solar generation (such amounts are included in the “Renewable projects” line in the table below).

| Alliant Energy |  | IPL |  | WPL
| 2020 | 2021 | 2022 | 2023 | 2024 |  | 2020 | 2021 | 2022 | 2023 | 2024 |  | 2020 | 2021 | 2022 | 2023 | 2024
Generation: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable projects |  | $265 |  |  | $485 |  |  | $750 |  |  | $635 |  |  | $320 |  |  |  | $120 |  |  | $45 |  |  | $270 |  |  | $270 |  |  | $50 |  |  |  | $145 |  |  | $440 |  |  | $480 |  |  | $365 |  |  | $270 |
Other | 150 |  | 90 |  | 180 |  | 175 |  | 90 |  |  | 50 |  | 45 |  | 135 |  | 135 |  | 55 |  |  | 100 |  | 45 |  | 45 |  | 40 |  | 35 |
Distribution: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Electric systems | 675 |  | 470 |  | 435 |  | 535 |  | 695 |  |  | 420 |  | 240 |  | 225 |  | 290 |  | 375 |  |  | 255 |  | 230 |  | 210 |  | 245 |  | 320 |
Gas systems | 170 |  | 70 |  | 75 |  | 70 |  | 70 |  |  | 50 |  | 35 |  | 40 |  | 30 |  | 30 |  |  | 120 |  | 35 |  | 35 |  | 40 |  | 40 |
Other | 120 |  | 180 |  | 185 |  | 190 |  | 195 |  |  | 30 |  | 10 |  | 10 |  | 10 |  | 25 |  |  | 10 |  | 15 |  | 10 |  | 10 |  | 10 |
|  | $1,380 |  |  | $1,295 |  |  | $1,625 |  |  | $1,605 |  |  | $1,370 |  |  |  | $670 |  |  | $375 |  |  | $680 |  |  | $735 |  |  | $535 |  |  |  | $630 |  |  | $765 |  |  | $780 |  |  | $700 |  |  | $675 |

| 35 |

Table of Contents
Financing Activities - The following items contributed to increased (decreased) financing activity cash flows for the nine months ended September 30, 2020 compared to the same period in 2019 (in millions):

| Alliant Energy |  | IPL |  | WPL
Lower (higher) payments to retire long-term debt |  | ($401 | ) |  |  | ($200 | ) |  |  | $100 |
Net changes in the amount of commercial paper outstanding | 177 |  |  | 50 |  |  | 76 |
Higher (lower) net proceeds from issuance of long-term debt | 100 |  |  | (200 | ) |  | — |
Higher net proceeds from common stock issuances | 56 |  |  | — |  |  | — |
Higher (lower) capital contributions from IPL’s and WPL’s parent company, Alliant Energy | — |  |  | 245 |  |  | (75 | )
Other (includes higher dividend payments in 2020) | (39 | ) |  | (54 | ) |  | (16 | )
|  | ($107 | ) |  |  | ($159 | ) |  |  | $85 |

IPL and WPL Solar Project Tax Equity Credits - IPL and WPL each propose to own and operate their planned solar projects, which are currently expected to qualify for 30% investment tax credits, through a tax equity partnership, with approximately 35% to 45% of the construction costs financed with capital from the tax equity partner. This would allow IPL’s and WPL’s customers to share the costs of the solar projects with an investment partner for 10 years or less, while ensuring their customers receive energy, capacity, and renewable energy credit benefits from the projects. IPL and WPL would expect to purchase the tax equity partner’s interest in the solar projects within 10 years of operation, and then convert to a traditional ownership structure for the remainder of the useful life of the projects. Assuming a portion of the construction costs are financed by the tax equity partner, IPL would receive approximately $205 million from the tax equity partner in 2023, and WPL would receive approximately $210 million in 2022 and $275 million in 2023. IPL and WPL would expect to include their portion of capital expenditures, less the amounts financed by the tax equity partner, in their respective rate base.
State Regulatory Financing Authorizations - In September 2020, WPL received authorization from the PSCW to issue up to $1 billion of long-term debt securities in aggregate through December 2023.
Common Stock Issuances and Common Stock Dividends - Refer to Note 5 for discussion of common stock issuances by Alliant Energy in 2020. Refer to “Results of Operations” for discussion of expected common stock dividends in 2021.
Long-term Debt - Refer to Note 6(b) for discussion of IPL’s, WPL’s and AEF’s issuances and retirements of long-term debt in 2020. Refer to “Results of Operations” for discussion of expected issuances of long-term debt in 2021.
Off-Balance Sheet Arrangements and Certain Financial Commitments - A summary of Alliant Energy’s and IPL’s off-balance sheet arrangements and Alliant Energy’s, IPL’s and WPL’s contractual obligations is included in the 2019 Form 10-K and has not changed materially from the items reported in the 2019 Form 10-K, except for the items described in Notes 3, 6 and 13.
OTHER MATTERS
Critical Accounting Policies and Estimates - The summary of critical accounting policies and estimates included in the 2019 Form 10-K has not changed materially, except as described below.
Contingencies - Effective January 1, 2020 upon the adoption of the new accounting standard for credit losses, certain contingencies, such as Alliant Energy Resources, LLC’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, require estimation each reporting period of the expected credit losses on those contingencies. These estimates require significant judgment and would result in recognition of a credit loss liability sooner than the previous accounting standards, which required recognition when the contingency became probable and could be reasonably estimated based on then currently available information. With respect to Alliant Energy’s guarantees of the partnership obligations of an affiliate of Whiting Petroleum, the most significant judgments in determining the credit loss liability were the estimate of the exposure under the guarantees and the methodology used for calculating the credit loss liability. As of September 30, 2020, Alliant Energy currently estimates the exposure to be a portion of the known partnership abandonment obligations. The methodology used to determine the credit loss liability considers both quantitative and qualitative information, which utilizes potential outcomes in a range of possible estimated amounts. Factors considered include market and external data points, the creditworthiness of the other partners, Whiting Petroleum’s emergence from bankruptcy in the third quarter of 2020, and a portion of forecasted cash flow expenditures associated with the abandonment obligations based on information made available to Alliant Energy. Note 1(c) provides discussion of the adoption of the new accounting standard for credit losses. Note 13(c) provides further discussion of contingencies assessed at January 1, 2020 and September 30, 2020, including impacts to Alliant Energy Resources, LLC’s guarantees in the partnership obligations of an affiliate of Whiting Petroleum and to the other partners, as well as adjustments to the credit loss liability recorded in the third quarter of 2020.
ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK
Quantitative and Qualitative Disclosures About Market Risk are reported in the 2019 Form 10-K and have not changed materially.

| 36 |

Table of Contents
ITEM 4. CONTROLS AND PROCEDURES
Alliant Energy’s, IPL’s and WPL’s management evaluated, with the participation of each of Alliant Energy’s, IPL’s and WPL’s Chief Executive Officer, Chief Financial Officer and Disclosure Committee, the effectiveness of the design and operation of Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures (as defined in Rule 13a-15(e) of the Securities Exchange Act of 1934) as of September 30, 2020 pursuant to the requirements of the Securities Exchange Act of 1934, as amended. Based on their evaluation, the Chief Executive Officer and the Chief Financial Officer concluded that Alliant Energy’s, IPL’s and WPL’s disclosure controls and procedures were effective as of the quarter ended September 30, 2020.
There was no change in Alliant Energy’s, IPL’s and WPL’s internal control over financial reporting that occurred during the quarter ended September 30, 2020 that has materially affected, or is reasonably likely to materially affect, Alliant Energy’s, IPL’s or WPL’s internal control over financial reporting. Alliant Energy, IPL and WPL have not experienced any material impact to their internal control over financial reporting due to the COVID-19 pandemic, and continue to monitor and assess the impact COVID-19 has on their internal controls.
PART II. OTHER INFORMATION
ITEM 1A. RISK FACTORS
The risk factors described in Item 1A in the 2019 Form 10-K have not changed materially, except as described below.
The recent outbreak of the novel coronavirus (COVID-19) pandemic could adversely affect our business functions, financial condition, results of operations and cash flows - The continued spread of the novel coronavirus (COVID-19) has resulted in widespread impacts on the economy and could lead to a prolonged reduction in economic activity, disruptions to supply chains and capital markets, and reduced labor availability and productivity. The COVID-19 pandemic has impacted and may continue to impact the economic conditions in our service territories, which may adversely impact our sales and our customers’ abilities to pay their bills. Travel and transportation restrictions and closures of commercial spaces and industrial facilities have been imposed in and across the U.S., including in the service territories in which we operate. Governmental and regulatory responses to COVID-19 include suspending service disconnects and waiving late fees, which may increase customer account arrears, possibly increasing our allowance for expected credit losses and decreasing our cash flows.
Although we expect an increase in residential sales due to these closures, our commercial and industrial sales may be significantly reduced. The negative impacts on the economy could adversely impact the market value of the assets that fund our pension plans, which could necessitate accelerated funding of the plans to meet minimum federal government requirements. The negative impacts on the economy could also adversely impact the ability of counterparties to meet contractual payment obligations, including guarantees, or deliver contracted commodities and other goods or services at the contracted price, which could increase company expenses. Our access to the capital markets could be adversely affected by COVID-19, which could cause us to need alternative sources of funding for our operations and for working capital, any of which could increase our cost of capital.
Travel bans and restrictions, quarantines, shelter in place orders and shutdowns may cause disruptions in supply chains or access to labor that may adversely impact our planned construction projects, our ability to satisfy compliance requirements, or our operations, including our ability to maintain reliable electric and gas service. This may cause us to miss milestones on construction projects and experience operational delays, which, in the case of renewable energy projects, could delay our completion of such projects past the in-service dates required to qualify for the maximum general renewable tax credits for investments in such renewable energy projects. We have already modified certain business practices consistent with government restrictions and best practices encouraged by government and regulatory authorities and are developing and implementing risk mitigation plans for critical items and services required to continue our operations. The effects of these government restrictions could adversely impact implementation of our regulatory plans and our operations. If our workforce contracts COVID-19, it could negatively impact our operations, including our ability to maintain reliable electric and gas service.
The degree to which COVID-19 may impact our business operations, financial condition and results of operations is unknown at this time and will depend on future developments, including the ultimate geographic spread of COVID-19, the severity of the disease, the duration of the outbreak, possible resurgence of the disease at a later date, and further actions that may be taken by governmental and regulatory authorities.

| 37 |

Table of Contents
ITEM 2. UNREGISTERED SALES OF EQUITY SECURITIES AND USE OF PROCEEDS
A summary of Alliant Energy common stock repurchases for the quarter ended September 30, 2020 was as follows:

|  | Total Number |  | Average Price |  | Total Number of Shares |  | Maximum Number (or Approximate
|  | of Shares |  | Paid Per |  | Purchased as Part of |  | Dollar Value) of Shares That May
Period |  | Purchased (a) |  | Share |  | Publicly Announced Plan |  | Yet Be Purchased Under the Plan (a)
July 1 through July 31 |  | 4,009 |  |  |  | $49.07 |  |  | — |  | N/A
August 1 through August 31 |  | 2,680 |  |  | 53.91 |  |  | — |  | N/A
September 1 through September 30 |  | 64 |  |  | 52.11 |  |  | — |  | N/A
|  | 6,753 |  |  | 51.02 |  |  | — |  |

(a) | All shares were purchased on the open market and held in a rabbi trust under the Alliant Energy Deferred Compensation Plan. There is no limit on the number of shares of Alliant Energy common stock that may be held under the Deferred Compensation Plan, which currently does not have an expiration date.

ITEM 6. EXHIBITS
The following Exhibits are filed herewith or incorporated herein by reference.

Exhibit Number | Description
3.1 | Amended and Restated Bylaws of Alliant Energy, effective October 27, 2020 (incorporated by reference to Exhibit 3.1 to Alliant Energy’s Form 8-K, filed October 29, 2020 (File No. 1-9894))
3.2 | Amended and Restated Bylaws of IPL, effective October 27, 2020 (incorporated by reference to Exhibit 3.2 to IPL’s Form 8-K, filed October 29, 2020 (File No. 1-4117))
3.3 | Amended and Restated Bylaws of WPL, effective October 27, 2020 (incorporated by reference to Exhibit 3.3 to WPL’s Form 8-K, filed October 29, 2020 (File No. 0-337))
31.1 | Certification of the Chief Executive Officer for Alliant Energy
31.2 | Certification of the Chief Financial Officer for Alliant Energy
31.3 | Certification of the Chief Executive Officer for IPL
31.4 | Certification of the Chief Financial Officer for IPL
31.5 | Certification of the Chief Executive Officer for WPL
31.6 | Certification of the Chief Financial Officer for WPL
32.1 | Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for Alliant Energy
32.2 | Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for IPL
32.3 | Written Statement of the Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C.§1350 for WPL
101.INS | Inline XBRL Instance Document - the instance document does not appear in the Interactive Data File because its XBRL tags are embedded within the Inline XBRL document
101.SCH | Inline XBRL Taxonomy Extension Schema Document
101.CAL | Inline XBRL Taxonomy Extension Calculation Linkbase Document
101.LAB | Inline XBRL Taxonomy Extension Label Linkbase Document
101.PRE | Inline XBRL Taxonomy Extension Presentation Linkbase Document
101.DEF | Inline XBRL Taxonomy Extension Definition Linkbase Document
104 | Cover Page Interactive Data File (embedded within the Inline XBRL document)

| 38 |

Table of Contents
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, Alliant Energy Corporation, Interstate Power and Light Company and Wisconsin Power and Light Company have each duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized on the 3rd day of November 2020.

ALLIANT ENERGY CORPORATION |
Registrant |
By: /s/ Benjamin M. Bilitz | Chief Accounting Officer and Controller
Benjamin M. Bilitz | (Principal Accounting Officer and Authorized Signatory)

INTERSTATE POWER AND LIGHT COMPANY |
Registrant |
By: /s/ Benjamin M. Bilitz | Chief Accounting Officer and Controller
Benjamin M. Bilitz | (Principal Accounting Officer and Authorized Signatory)

WISCONSIN POWER AND LIGHT COMPANY |
Registrant |
By: /s/ Benjamin M. Bilitz | Chief Accounting Officer and Controller
Benjamin M. Bilitz | (Principal Accounting Officer and Authorized Signatory)

| 39 |