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Income Taxes (Tables) | 6 Months Ended
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Jun. 30, 2024
Income Taxes [Line Items] |
Schedule Of Effective Income Tax Rates | Overall effective income tax rates for the three and six months ended June 30, 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, investment tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. Also impacting Alliant Energy’s and IPL’s effective income tax rates for the three and six months ended June 30, 2024 were the pre-tax non-cash charge of $60 million for IPL’s Lansing Generation Station discussed in Note 2 and the pre-tax non-cash charge of $20 million for the portion of recorded AROs allocated to IPL’s steam business discussed in Note 11.
| Alliant Energy |  | IPL |  | WPL
| Three Months |  | Six Months |  | Three Months |  | Six Months |  | Three Months |  | Six Months
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Overall income tax rate | (61%) |  | —% |  | (21%) |  | (1%) |  | 220% |  | (17%) |  | (113%) |  | (18%) |  | 4% |  | 16% |  | 5% |  | 14%
Summary Of Tax Credit Carryforwards | At June 30, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
State net operating losses | 2025-2044 |  | $386 |  | $6 |  | $1
Federal tax credits | 2032-2044 |  | 631 |  | 405 |  | 216
IPL [Member] |
Income Taxes [Line Items] |
Schedule Of Effective Income Tax Rates | Overall effective income tax rates for the three and six months ended June 30, 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, investment tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. Also impacting Alliant Energy’s and IPL’s effective income tax rates for the three and six months ended June 30, 2024 were the pre-tax non-cash charge of $60 million for IPL’s Lansing Generation Station discussed in Note 2 and the pre-tax non-cash charge of $20 million for the portion of recorded AROs allocated to IPL’s steam business discussed in Note 11.
| Alliant Energy |  | IPL |  | WPL
| Three Months |  | Six Months |  | Three Months |  | Six Months |  | Three Months |  | Six Months
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Overall income tax rate | (61%) |  | —% |  | (21%) |  | (1%) |  | 220% |  | (17%) |  | (113%) |  | (18%) |  | 4% |  | 16% |  | 5% |  | 14%
Summary Of Tax Credit Carryforwards | At June 30, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
State net operating losses | 2025-2044 |  | $386 |  | $6 |  | $1
Federal tax credits | 2032-2044 |  | 631 |  | 405 |  | 216
WPL [Member] |
Income Taxes [Line Items] |
Schedule Of Effective Income Tax Rates | Overall effective income tax rates for the three and six months ended June 30, 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, investment tax credits, amortization of excess deferred taxes and the effect of rate-making on property-related differences. Also impacting Alliant Energy’s and IPL’s effective income tax rates for the three and six months ended June 30, 2024 were the pre-tax non-cash charge of $60 million for IPL’s Lansing Generation Station discussed in Note 2 and the pre-tax non-cash charge of $20 million for the portion of recorded AROs allocated to IPL’s steam business discussed in Note 11.
| Alliant Energy |  | IPL |  | WPL
| Three Months |  | Six Months |  | Three Months |  | Six Months |  | Three Months |  | Six Months
| 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023 |  | 2024 |  | 2023
Overall income tax rate | (61%) |  | —% |  | (21%) |  | (1%) |  | 220% |  | (17%) |  | (113%) |  | (18%) |  | 4% |  | 16% |  | 5% |  | 14%
Summary Of Tax Credit Carryforwards | At June 30, 2024, the carryforwards and expiration dates were estimated as follows (in millions):
| Range of Expiration Dates |  | Alliant Energy |  | IPL |  | WPL
State net operating losses | 2025-2044 |  | $386 |  | $6 |  | $1
Federal tax credits | 2032-2044 |  | 631 |  | 405 |  | 216

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- Definition Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Paragraph 12 -Section 50 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-12 + Details
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