XML 133 R51.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Electric utility segment Additional Information (Details) (USD $) | 12 Months Ended | 0 Months Ended | 3 Months Ended | 0 Months Ended | 1 Months Ended | 3 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2014 agreement | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 30, 2014 | May 31, 2013 | Nov. 30, 2013 | Jun. 30, 2013 | Jun. 30, 2014 | Jul. 11, 2013 MW | Nov. 30, 2013 | Feb. 28, 2013 bid | May 31, 2012 MW | Feb. 28, 2012 | Dec. 31, 2009 | Mar. 31, 2012 | Dec. 31, 2011 | Feb. 16, 2012 generation_unit | Feb. 07, 2014 | Jul. 31, 2014
Power purchase agreements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of power purchase agreements (PPAs) | 7 he_NumberOfPowerPurchaseAgreements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hawaiian Electric Company, Inc (HECO) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power purchase agreements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of power purchase agreements (PPAs) | 7 he_NumberOfPowerPurchaseAgreements / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchased power | 537,821,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 527,839,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | $ 540,802,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable projects |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Generating Units Subject to New Regulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 14 he_NumberofGeneratingUnitsSubjecttoNewRegulation / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |
D&O |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues | 2,142,245,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 2,124,174,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 2,228,233,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hawaii Electric Light Company, Inc. (HELCO) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power purchase agreements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchased power | 123,226,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 128,368,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 145,386,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
D&O |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues | 422,200,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 431,517,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 441,013,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maui Electric Company, Limited (MECO) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power purchase agreements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchased power | 60,961,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 54,474,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 38,052,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Environmental regulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Additional accrued investigation and estimated cleanup costs | 3,600,000 he_ReserveForAdditionalInvestigationAndEstimatedCleanupCosts / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  | 3,100,000 he_ReserveForAdditionalInvestigationAndEstimatedCleanupCosts / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |
D&O |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues | 422,965,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 424,603,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 440,270,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  | 5,300,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reductions in D&O |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Lower ROACE |  | 4,000,000 he_LowerReturnOnCommonEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Customer Information System expenses |  | 300,000 he_CustomerInformationSystemExpenses / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Pension and OPEB expense based on 3-year average |  | 1,500,000 he_PensionAndOPEBExpense / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Integrated resource planning expenses |  | 900,000 he_IntegratedResourcePlanningExpenses / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Operational and Renewable Energy Integration study costs |  | 1,100,000 he_StudyCosts / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total adjustment | 7,800,000 he_AdjustmentsForDecisionAndOrderOfPUC / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 7,800,000 he_AdjustmentsForDecisionAndOrderOfPUC / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stipulated return on common equity percentage | 10.00%he_StipulatedReturnOnCommonEquityPercentage / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return on common equity percentage approved by PUC | 9.00%he_ReturnOnCommonEquityPercentageApprovedByPUC / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return on common equity percentage approved by PUC allocated to lower interest rate | 0.50%he_ReturnOnCommonEquityPercentageApprovedByPUCAllocatedToLowerInterestRate / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Return on common equity percentage approved by PUC allocated for OverCurtailment of renewable energy | 0.50%he_ReturnOnCommonEquityPercentageApprovedByPUCAllocatedForOverCurtailmentOfRenewableEnergy / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Period as basis for calculation of average pension cost | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Charge recorded net of revenue taxes |  |  |  |  |  |  | 7,600,000 he_ChargeRecordedNetOfRevenueTaxes / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |
Amount to be refunded to customers |  |  |  |  |  | 9,700,000 he_AmountToBeRefundedToCustomers / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (decrease) in employee benefit expenses |  |  |  |  |  |  | (1,800,000)he_IncreaseDecreaseInEmployeeBenefitExpenses / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |
Deferred IRP cost allowed by PUC order, reclassified to deferred accounts |  |  |  |  |  |  | 700,000 he_DeferredIRPCostAllowedByPUCOrderReclassifiedToDeferredAccounts / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |
General Rate Case Cycle Period |  |  |  | 3 years |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated increase in revenue, if base rate increased | 11,600,000 he_EstimatedIncreaseDecreaseInRevenueDueToChangeInBaseRate / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated increase in revenue, if base rate increased, percentage | 2.80%he_EstimatedIncreaseDecreaseInRevenueDueToChangeInBaseRatePercentage / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated cost of common equity, percentage | 10.75%he_EstimatedCostOfCommonEquityPercentage / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fuel contracts |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated cost of minimum purchase within 2015 year | 400,000,000 he_LongTermPurchaseCommitmentAmountWithinOneYear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated cost of minimum purchase in 2016 year | 300,000,000 he_LongTermPurchaseCommitmentAmountInSecondYear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Estimated cost of minimum purchase in 2017 year | 6,400,000 he_LongTermPurchaseCommitmentAmountInThirdYear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cost of purchases | 1,100,000,000 he_CostOfPurchases / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,100,000,000 he_CostOfPurchases / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,300,000,000 he_CostOfPurchases / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power purchase agreements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Power purchase capacity excluding agreements with smaller IPPs (in megawatts) | 575 he_AggregateOfPowerPurchaseCapacityExcludingAgreementWithSmallerIndependentPowerProducers / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchased power | 722,008,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 710,681,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 724,240,000 us-gaap_UtilitiesOperatingExpensePurchasedPower / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected fixed capacity charges per year for 2015 through 2019, minimum | 100,000,000 he_UtilitiesMinimumExpectedFixedCapacityChargesPerYearOneThroughFiveYears / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Expected fixed capacity charges from 2019 through 2033 | 500,000,000 he_UtilitiesExpectedFixedCapacityChargesafterFiveThroughTwentyYears / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable projects |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of renewable portfolio standard to be achieved by 2030 |  |  |  |  |  |  |  |  |  |  |  |  |  | 40.00%he_PercentageOfExpectedRenewablePortfolioStandard / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |
Recovery of annual deferred costs contingent on approval |  |  |  |  |  |  |  |  |  | 405,000 he_PublicUtilitiesRecoveryOfAnnualDeferredCostsContingentOnApproval / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |
Integration from renewable energy sources (in megawatts) |  | 200 he_CapacityIntegrationFromRenewableEnergySources / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  | 200 he_CapacityIntegrationFromRenewableEnergySources / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |
Maximum deferred cost recovery |  |  |  |  |  |  |  |  |  |  |  |  | 5,890,000 he_UtilitiesMaximumDeferredCostRecoveryPerYear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |
Integration from firm renewable geothermal dispatchable energy (in megawatts) |  |  |  |  |  |  |  |  |  |  |  | 50 he_CapacityIntegrationFromDispatchableRenewableGeothermalSources / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |
Number of bids received |  |  |  |  |  |  |  |  |  |  | 6 he_NumberOfBidsReceived / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |
Environmental regulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Percentage of reduction in GHG emissions by 2020 |  |  |  |  |  |  |  | 16.00%he_PercentageOfGreenHouseGasEmissionBy2020 / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |
Estimated annual fee, emissions regulation | 500,000 he_EmissionsRegulationsEstimatedAnnualFee / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
D&O |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues | 2,987,323,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 2,980,172,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 3,109,439,000 us-gaap_RegulatedOperatingRevenueElectricNonNuclear / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Changes in the asset retirement obligation liability |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Balance at the beginning of the period | 43,106,000 us-gaap_AssetRetirementObligation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 48,431,000 us-gaap_AssetRetirementObligation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Accretion expense | 890,000 us-gaap_AssetRetirementObligationAccretionExpense / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,263,000 us-gaap_AssetRetirementObligationAccretionExpense / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Liabilities incurred | 0 us-gaap_AssetRetirementObligationLiabilitiesIncurred / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 0 us-gaap_AssetRetirementObligationLiabilitiesIncurred / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Liabilities settled | (14,577,000)us-gaap_AssetRetirementObligationLiabilitiesSettled / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | (5,672,000)us-gaap_AssetRetirementObligationLiabilitiesSettled / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Revisions in estimated cash flows | 0 us-gaap_AssetRetirementObligationRevisionOfEstimate / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | (916,000)us-gaap_AssetRetirementObligationRevisionOfEstimate / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Balance at the end of the period | 29,419,000 us-gaap_AssetRetirementObligation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 43,106,000 us-gaap_AssetRetirementObligation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 48,431,000 us-gaap_AssetRetirementObligation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Decoupling |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, baseline capital project value to determine revenue adjustment | 2,500,000 he_PublicUtilitiesBaselineCapitalProjectValuetoDetermineRevenueAdjustment / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, proposed rate base adjustment, percent of previous rate base adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 90.00%he_PublicUtilitiesProposedRateBaseAdjustmentPercentofPreviousRateBaseAdjustment / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |
Public Utilites, effective interest rate, revenue balancing account | 6.00%he_PublicUtilitiesEffectiveInterestRateRevenueBalancingAccount / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Decoupling |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, proposed effective interest rate, revenue balancing account |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.25%he_PublicUtilitiesProposedEffectiveInterestRateRevenueBalancingAccount / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember / us-gaap_RangeAxis = us-gaap_MinimumMember |
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Decoupling |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Public Utilities, proposed effective interest rate, revenue balancing account |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3.25%he_PublicUtilitiesProposedEffectiveInterestRateRevenueBalancingAccount / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember / us-gaap_RangeAxis = us-gaap_MaximumMember |
East Oahu Transmission Project Phase 1 | Hawaiian Electric Company, Inc. and Subsidiaries |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable projects |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Gross plant cost agreed to be written-off in lieu of regulatory audit |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 9,500,000 he_PlantCostAgreedToBeWrittenOff / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember / he_RegulatoryProjectsAndLegalObligationsAxis = he_EastOahuTransmissionProjectPhase1Member |  |  |  |
After-tax charge to net income due to settlement agreement |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 6,000,000 he_ImpactOfSettlementAgreementOnNetIncomeLossNetOfTax / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember / he_RegulatoryProjectsAndLegalObligationsAxis = he_EastOahuTransmissionProjectPhase1Member |  |  |
Additional increase in test year rate case |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 5,000,000 he_AdditionalIncreaseinTestYearRateCase / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember / he_RegulatoryProjectsAndLegalObligationsAxis = he_EastOahuTransmissionProjectPhase1Member |  |  |  |
Reserve for environmental costs |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Environmental regulation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reserve for additional investigation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 800,000 us-gaap_ValuationAllowancesAndReservesBalance / us-gaap_ValuationAllowancesAndReservesTypeAxis = us-gaap_ReserveForEnvironmentalCostsMember

X
- Definition Additional Increase in Test Year Rate Case + References No definition available. + Details
Name: | he_AdditionalIncreaseinTestYearRateCase
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the adjustments for interim decision and order of PUC. + References No definition available. + Details
Name: | he_AdjustmentsForDecisionAndOrderOfPUC
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the entity's aggregate capacity utilized under power purchase agreements (PPAs) excluding power purchase agreements with smaller independent power producers and schedule Q providers. + References No definition available. + Details
Name: | he_AggregateOfPowerPurchaseCapacityExcludingAgreementWithSmallerIndependentPowerProducers
Namespace Prefix: | he_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the amount to be refunded to customers. + References No definition available. + Details
Name: | he_AmountToBeRefundedToCustomers
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the capacity integration from dispatchable renewable geothermal sources. + References No definition available. + Details
Name: | he_CapacityIntegrationFromDispatchableRenewableGeothermalSources
Namespace Prefix: | he_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the capacity integration to the grid from renewable energy sources, including solar, biomass, wind, ocean thermal energy conversion, wave and others. + References No definition available. + Details
Name: | he_CapacityIntegrationFromRenewableEnergySources
Namespace Prefix: | he_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the charge recorded net of revenue taxes as final rate increase was lower than the interim increase. + References No definition available. + Details
Name: | he_ChargeRecordedNetOfRevenueTaxes
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the actual cost of purchases. + References No definition available. + Details
Name: | he_CostOfPurchases
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the customer information system expenses. + References No definition available. + Details
Name: | he_CustomerInformationSystemExpenses
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | he_DecouplingAbstract
Namespace Prefix: | he_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Deferred IRP Cost Allowed By PUC Order, Reclassified To Deferred Accounts + References No definition available. + Details
Name: | he_DeferredIRPCostAllowedByPUCOrderReclassifiedToDeferredAccounts
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | he_DirectorandOfficerLiabilityInsuranceAbstract
Namespace Prefix: | he_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Emissions Regulations, Estimated Annual Fee + References No definition available. + Details
Name: | he_EmissionsRegulationsEstimatedAnnualFee
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Estimated Cost Of Common Equity, Percentage + References No definition available. + Details
Name: | he_EstimatedCostOfCommonEquityPercentage
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Estimated Increase (Decrease) In Revenue, Due To Change In Base Rate + References No definition available. + Details
Name: | he_EstimatedIncreaseDecreaseInRevenueDueToChangeInBaseRate
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Estimated Increase (Decrease) In Revenue, Due To Change In Base Rate, Percentage + References No definition available. + Details
Name: | he_EstimatedIncreaseDecreaseInRevenueDueToChangeInBaseRatePercentage
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | he_FuelSupplyContractsAbstract
Namespace Prefix: | he_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition General Rate Case Cycle Period + References No definition available. + Details
Name: | he_GeneralRateCaseCyclePeriod
Namespace Prefix: | he_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the after-tax impact of the settlement agreement on the income or loss of the entity. + References No definition available. + Details
Name: | he_ImpactOfSettlementAgreementOnNetIncomeLossNetOfTax
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the increase or decrease in employee benefits expenses. + References No definition available. + Details
Name: | he_IncreaseDecreaseInEmployeeBenefitExpenses
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the integrated resource planning expenses. + References No definition available. + Details
Name: | he_IntegratedResourcePlanningExpenses
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The minimum estimated amount in the second year after the balance sheet date the entity agreed to spend under the long-term purchase commitment. + References No definition available. + Details
Name: | he_LongTermPurchaseCommitmentAmountInSecondYear
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The minimum estimated amount in the third year after the balance sheet date the entity agreed to spend under the long-term purchase commitment. + References No definition available. + Details
Name: | he_LongTermPurchaseCommitmentAmountInThirdYear
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The minimum estimated amount in the first year after the balance sheet date the entity agreed to spend under the long-term purchase commitment. + References No definition available. + Details
Name: | he_LongTermPurchaseCommitmentAmountWithinOneYear
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the lower return on common equity. + References No definition available. + Details
Name: | he_LowerReturnOnCommonEquity
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the number of bids received. + References No definition available. + Details
Name: | he_NumberOfBidsReceived
Namespace Prefix: | he_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Generating Units Subject to New Regulation + References No definition available. + Details
Name: | he_NumberofGeneratingUnitsSubjecttoNewRegulation
Namespace Prefix: | he_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of firm power purchase agreements entered into, by the company. + References No definition available. + Details
Name: | he_NumberOfPowerPurchaseAgreements
Namespace Prefix: | he_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the pension and OPEB expense based on 3-year average. + References No definition available. + Details
Name: | he_PensionAndOPEBExpense
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the percentage of renewable portfolio standard to be achieved by 2030. + References No definition available. + Details
Name: | he_PercentageOfExpectedRenewablePortfolioStandard
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of reduction in green house gases emission level by 2020. + References No definition available. + Details
Name: | he_PercentageOfGreenHouseGasEmissionBy2020
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the period for calculating average pension costs. + References No definition available. + Details
Name: | he_PeriodAsBasisForCalculationOfAveragePensionCost
Namespace Prefix: | he_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the plant cost agreed to be written-off by the entity as per the terms of settlement agreement. + References No definition available. + Details
Name: | he_PlantCostAgreedToBeWrittenOff
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | he_PowerPurchaseAgreementsAbstract
Namespace Prefix: | he_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Public Utilities, Baseline Capital Project Value to Determine Revenue Adjustment + References No definition available. + Details
Name: | he_PublicUtilitiesBaselineCapitalProjectValuetoDetermineRevenueAdjustment
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Public Utilities, Effective Interest Rate, Revenue Balancing Account + References No definition available. + Details
Name: | he_PublicUtilitiesEffectiveInterestRateRevenueBalancingAccount
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Proposed Effective Interest Rate, Revenue Balancing Account + References No definition available. + Details
Name: | he_PublicUtilitiesProposedEffectiveInterestRateRevenueBalancingAccount
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Proposed Rate Base Adjustment, Percent of Previous Rate Base Adjustment + References No definition available. + Details
Name: | he_PublicUtilitiesProposedRateBaseAdjustmentPercentofPreviousRateBaseAdjustment
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Public Utilities, Recovery Of Annual Deferred Costs Contingent On Approval + References No definition available. + Details
Name: | he_PublicUtilitiesRecoveryOfAnnualDeferredCostsContingentOnApproval
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | he_ReductionsInDirectorsAndOfficersLiabilityInsuranceAbstract
Namespace Prefix: | he_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | he_RenewableProjectsAbstract
Namespace Prefix: | he_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the amount of additional accrued investigation and estimated cleanup costs. + References No definition available. + Details
Name: | he_ReserveForAdditionalInvestigationAndEstimatedCleanupCosts
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the final approved ROACE percentage. + References No definition available. + Details
Name: | he_ReturnOnCommonEquityPercentageApprovedByPUC
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the final approved ROACE percentage allocated for over curtailment of renewable energy. + References No definition available. + Details
Name: | he_ReturnOnCommonEquityPercentageApprovedByPUCAllocatedForOverCurtailmentOfRenewableEnergy
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the final approved ROACE percentage allocated to lower interest rates. + References No definition available. + Details
Name: | he_ReturnOnCommonEquityPercentageApprovedByPUCAllocatedToLowerInterestRate
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of stipulated ROACE. + References No definition available. + Details
Name: | he_StipulatedReturnOnCommonEquityPercentage
Namespace Prefix: | he_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the study costs. + References No definition available. + Details
Name: | he_StudyCosts
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the total amount of expected fixed capacity charges in the period for years six through twenty years. + References No definition available. + Details
Name: | he_UtilitiesExpectedFixedCapacityChargesafterFiveThroughTwentyYears
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the deferred cost of the wind project to be recovered by the entity per year according to the PUC approval. + References No definition available. + Details
Name: | he_UtilitiesMaximumDeferredCostRecoveryPerYear
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Represents the minimum amount of expected fixed capacity charges per year for years one through five. + References No definition available. + Details
Name: | he_UtilitiesMinimumExpectedFixedCapacityChargesPerYearOneThroughFiveYears
Namespace Prefix: | he_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Asset Retirement Obligation -URI http://asc.fasb.org/extlink&oid=6505190 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationAccretionExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of asset retirement obligations incurred during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationLiabilitiesIncurred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationLiabilitiesSettled
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c)(4) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationRevisionOfEstimate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_AssetRetirementObligationRollForwardAnalysisRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_EnvironmentalRemediationObligationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of regulated power revenues recognized during the period. + References No definition available. + Details
Name: | us-gaap_RegulatedOperatingRevenueElectricNonNuclear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of operating expense for purchased power of regulated operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.2(b)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_UtilitiesOperatingExpensePurchasedPower
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 09 -Article 12 + Details
Name: | us-gaap_ValuationAllowancesAndReservesBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=he_HawaiianElectricCompanyAndSubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=he_SubsidiariesThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=he_SubsidiariesTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=us-gaap_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | he_RegulatoryProjectsAndLegalObligationsAxis=he_EastOahuTransmissionProjectPhase1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ValuationAllowancesAndReservesTypeAxis=us-gaap_ReserveForEnvironmentalCostsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |