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v2.4.1.9

Electric utility segment Consolidating Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2007
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Utility property, plant and equipment |  |  |  |  |
Property, plant and equipment, net | $ 4,148,774 us-gaap_PropertyPlantAndEquipmentNet | $ 3,865,514 us-gaap_PropertyPlantAndEquipmentNet |  |  |
Other long-term assets |  |  |  |  |
Total assets | 11,184,161 us-gaap_Assets | 10,340,044 us-gaap_Assets |  |  |
Capitalization |  |  |  |  |
Common stock equity | 1,791,428 us-gaap_StockholdersEquity | 1,727,070 us-gaap_StockholdersEquity | 1,593,865 us-gaap_StockholdersEquity | 1,528,706 us-gaap_StockholdersEquity |
Cumulative preferred stock-not subject to mandatory redemption | 0 us-gaap_PreferredStockValue | 0 us-gaap_PreferredStockValue |  |  |
Current liabilities |  |  |  |  |
Interest and dividends payable | 25,336 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries | 26,716 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries |  |  |
Deferred credits and other liabilities |  |  |  |  |
Deferred income taxes | 631,734 us-gaap_DeferredTaxLiabilitiesNoncurrent | 529,260 us-gaap_DeferredTaxLiabilitiesNoncurrent |  |  |
Contributions in aid of construction | 466,432 us-gaap_ContributionsInAidOfConstruction | 432,894 us-gaap_ContributionsInAidOfConstruction |  |  |
Total liabilities and shareholders' equity | 11,184,161 us-gaap_LiabilitiesAndStockholdersEquity | 10,340,044 us-gaap_LiabilitiesAndStockholdersEquity |  |  |
HECO |  |  |  |  |
Utility property, plant and equipment |  |  |  |  |
Land | 43,819 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 43,407 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Plant and equipment | 3,782,438 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 3,558,569 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Less accumulated depreciation | (1,253,866)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | (1,222,129)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Construction in progress | 134,376 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 124,494 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Utility property, plant and equipment, net | 2,706,767 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 2,504,341 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Nonutility property, plant and equipment, less accumulated depreciation | 4,950 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 4,953 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Property, plant and equipment, net | 2,711,717 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 2,509,294 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Investment in wholly-owned subsidiaries, at equity | 538,639 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 523,674 us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Current assets |  |  |  |  |
Cash and cash equivalents | 12,416 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 61,245 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 8,265 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 44,819 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Advances to affiliates | 16,100 us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 6,839 us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Customer accounts receivable, net | 111,462 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 121,282 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Accrued unbilled revenues, net | 103,072 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 107,752 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Other accounts receivable, net | 9,980 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 16,373 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Fuel oil stock, at average cost | 74,515 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 99,613 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Materials and supplies, at average cost | 33,154 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 37,377 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Prepayments and other | 44,680 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 29,798 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Regulatory assets | 58,550 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 54,979 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total current assets | 463,929 us-gaap_AssetsCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 535,258 us-gaap_AssetsCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Other long-term assets |  |  |  |  |
Regulatory assets | 623,784 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 381,346 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Unamortized debt expense | 5,640 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 6,051 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Other | 53,106 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 42,163 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total other long-term assets | 682,530 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 429,560 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total assets | 4,396,815 us-gaap_Assets / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 3,997,786 us-gaap_Assets / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Capitalization |  |  |  |  |
Common stock equity | 1,682,144 us-gaap_StockholdersEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 1,593,564 us-gaap_StockholdersEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 1,472,136 us-gaap_StockholdersEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 1,402,841 us-gaap_StockholdersEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |
Cumulative preferred stock-not subject to mandatory redemption | 22,293 us-gaap_PreferredStockValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 22,293 us-gaap_PreferredStockValue / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Long-term debt, net | 830,546 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 830,547 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total capitalization | 2,534,983 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 2,446,404 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Current liabilities |  |  |  |  |
Current portion of long-term debt | 0 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |  |
Short-term borrowings-affiliate | 0 us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 1,000 us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Accounts payable | 122,433 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 145,062 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Interest and dividends payable | 15,407 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 15,190 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Taxes accrued | 176,339 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 175,790 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Regulatory liabilities | 191 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 1,705 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Other | 48,282 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 48,443 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total current liabilities | 362,652 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 387,190 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Deferred credits and other liabilities |  |  |  |  |
Deferred income taxes | 429,515 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 359,621 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Regulatory liabilities | 236,727 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 235,786 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Unamortized tax credits | 49,865 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 44,931 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Defined benefit pension and other postretirement benefit plans liability | 446,888 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 202,396 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Other | 52,446 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 63,374 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total deferred credits and other liabilities | 1,215,441 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 906,108 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Contributions in aid of construction | 283,739 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 258,084 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Total liabilities and shareholders' equity | 4,396,815 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember | 3,997,786 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = us-gaap_SubsidiariesMember |  |  |
Consolidating adjustments |  |  |  |  |
Utility property, plant and equipment |  |  |  |  |
Nonutility property, plant and equipment, less accumulated depreciation | 0 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |  |
Investment in wholly-owned subsidiaries, at equity | (538,639)us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (523,674)us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Current assets |  |  |  |  |
Advances to affiliates | (16,100)us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (7,839)us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Other accounts receivable, net | (8,924)us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (9,027)us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Prepayments and other | (475)us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (1,415)us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Total current assets | (25,499)us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (18,281)us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Other long-term assets |  |  |  |  |
Regulatory assets | (183)us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |  |
Total other long-term assets | (183)he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |  |
Total assets | (564,321)us-gaap_Assets / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (541,955)us-gaap_Assets / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Capitalization |  |  |  |  |
Common stock equity | (538,639)us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (523,674)us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (497,939)us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (516,143)us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |
Total capitalization | (538,639)us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (523,674)us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Current liabilities |  |  |  |  |
Current portion of long-term debt | 0 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |  |
Short-term borrowings-affiliate | (16,100)us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (7,839)us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Interest and dividends payable | (11)he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (8)he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Taxes accrued | (292)us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (1,415)us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Regulatory liabilities |  | 0 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Other | (9,096)us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (9,019)us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Total current liabilities | (25,499)us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (18,281)us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Deferred credits and other liabilities |  |  |  |  |
Regulatory liabilities | (183)us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | 0 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
Total deferred credits and other liabilities | (183)us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |  |
Total liabilities and shareholders' equity | (564,321)us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember | (541,955)us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_ConsolidationReclassificationsAndEliminationsMember |  |  |
HELCO |  |  |  |  |
Utility property, plant and equipment |  |  |  |  |
Land | 5,464 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 5,460 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Plant and equipment | 1,179,032 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 1,136,923 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Less accumulated depreciation | (473,933)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = he_SubsidiariesTwoMember | (453,721)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Construction in progress | 12,421 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 7,709 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Utility property, plant and equipment, net | 722,984 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 696,371 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Nonutility property, plant and equipment, less accumulated depreciation | 82 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 82 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Property, plant and equipment, net | 723,066 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 696,453 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Current assets |  |  |  |  |
Cash and cash equivalents | 612 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 1,326 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 5,441 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 3,383 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesTwoMember |
Advances to affiliates | 0 us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 1,000 us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Customer accounts receivable, net | 24,222 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 28,088 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Accrued unbilled revenues, net | 15,926 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 17,100 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Other accounts receivable, net | 981 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 4,265 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Fuel oil stock, at average cost | 13,800 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 14,178 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Materials and supplies, at average cost | 6,664 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 6,883 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Prepayments and other | 8,611 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 8,334 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Regulatory assets | 6,745 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 6,931 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total current assets | 77,561 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 88,105 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Other long-term assets |  |  |  |  |
Regulatory assets | 107,454 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 64,552 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  | 12,800 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember
Unamortized debt expense | 1,438 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 1,580 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Other | 15,366 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 11,270 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total other long-term assets | 124,258 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 77,402 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total assets | 924,885 us-gaap_Assets / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 861,960 us-gaap_Assets / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Capitalization |  |  |  |  |
Common stock equity | 281,846 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 274,802 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 268,908 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 280,468 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember |
Cumulative preferred stock-not subject to mandatory redemption | 7,000 us-gaap_PreferredStockValue / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 7,000 us-gaap_PreferredStockValue / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Long-term debt, net | 190,000 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 189,998 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total capitalization | 478,846 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 471,800 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Current liabilities |  |  |  |  |
Current portion of long-term debt | 0 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 11,400 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Short-term borrowings-affiliate | 10,500 us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |  |
Accounts payable | 23,728 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 24,383 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Interest and dividends payable | 3,989 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 3,885 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Taxes accrued | 37,548 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 37,899 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Regulatory liabilities |  | 0 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Other | 9,866 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 9,033 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total current liabilities | 85,631 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 86,600 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Deferred credits and other liabilities |  |  |  |  |
Deferred income taxes | 90,119 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 79,947 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Regulatory liabilities | 77,707 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 76,475 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Unamortized tax credits | 14,902 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 14,245 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Defined benefit pension and other postretirement benefit plans liability | 72,547 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 28,427 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Other | 10,658 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 14,703 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total deferred credits and other liabilities | 265,933 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 213,797 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Contributions in aid of construction | 94,475 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 89,763 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
Total liabilities and shareholders' equity | 924,885 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember | 861,960 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesTwoMember |  |  |
MECO |  |  |  |  |
Utility property, plant and equipment |  |  |  |  |
Land | 3,016 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 3,016 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Plant and equipment | 1,048,012 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 1,006,383 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Less accumulated depreciation | (447,711)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = he_SubsidiariesThreeMember | (435,379)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Construction in progress | 11,819 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 11,030 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Utility property, plant and equipment, net | 615,136 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 585,050 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Nonutility property, plant and equipment, less accumulated depreciation | 1,531 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 1,532 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Property, plant and equipment, net | 616,667 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 586,582 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Current assets |  |  |  |  |
Cash and cash equivalents | 633 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 153 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 3,349 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 496 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_SubsidiariesThreeMember |
Advances to affiliates |  | 0 us-gaap_AdvancesToAffiliate / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Customer accounts receivable, net | 22,800 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 26,078 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Accrued unbilled revenues, net | 18,376 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 19,272 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Other accounts receivable, net | 2,246 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 2,451 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Fuel oil stock, at average cost | 17,731 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 20,296 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Materials and supplies, at average cost | 17,432 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 14,784 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Prepayments and other | 13,567 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 16,140 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Regulatory assets | 6,126 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 7,828 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total current assets | 98,911 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 107,002 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Other long-term assets |  |  |  |  |
Regulatory assets | 102,788 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 60,288 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Unamortized debt expense | 1,245 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 1,372 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Other | 13,366 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 13,993 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total other long-term assets | 117,399 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 75,653 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total assets | 832,977 us-gaap_Assets / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 769,237 us-gaap_Assets / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Capitalization |  |  |  |  |
Common stock equity | 256,692 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 248,771 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 228,927 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 235,568 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember |
Cumulative preferred stock-not subject to mandatory redemption | 5,000 us-gaap_PreferredStockValue / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 5,000 us-gaap_PreferredStockValue / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Long-term debt, net | 186,000 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 186,000 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total capitalization | 447,692 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 439,771 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Current liabilities |  |  |  |  |
Current portion of long-term debt | 0 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |  |
Short-term borrowings-affiliate | 5,600 us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 6,839 us-gaap_DueToAffiliateCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Accounts payable | 17,773 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 20,114 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Interest and dividends payable | 2,931 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 2,585 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Taxes accrued | 36,807 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 37,171 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Regulatory liabilities | 441 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 211 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Other | 16,094 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 15,424 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total current liabilities | 79,646 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 82,344 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Deferred credits and other liabilities |  |  |  |  |
Deferred income taxes | 83,238 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 67,593 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Regulatory liabilities | 29,966 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 35,122 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Unamortized tax credits | 14,725 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 14,363 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Defined benefit pension and other postretirement benefit plans liability | 75,960 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 31,339 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Other | 13,532 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 13,658 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total deferred credits and other liabilities | 217,421 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 162,075 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Contributions in aid of construction | 88,218 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 85,047 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
Total liabilities and shareholders' equity | 832,977 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember | 769,237 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_SubsidiariesThreeMember |  |  |
HECO Consolidated |  |  |  |  |
Utility property, plant and equipment |  |  |  |  |
Land | 52,299 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 51,883 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentLand / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Plant and equipment | 6,009,482 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 5,701,875 he_PublicUtilitiesPropertyPlantAndEquipmentTransmissionDistributionGenerationAndOther / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Less accumulated depreciation | (2,175,510)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | (2,111,229)us-gaap_PublicUtilitiesPropertyPlantAndEquipmentAccumulatedDepreciation / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Construction in progress | 158,616 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 143,233 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentConstructionWorkInProgress / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Utility property, plant and equipment, net | 4,044,887 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 3,785,762 us-gaap_PublicUtilitiesPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Nonutility property, plant and equipment, less accumulated depreciation | 6,563 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 6,567 us-gaap_PropertyPlantAndEquipmentOtherNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Property, plant and equipment, net | 4,051,450 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 3,792,329 us-gaap_PropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Current assets |  |  |  |  |
Cash and cash equivalents | 13,762 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 62,825 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 17,159 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 48,806 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |
Customer accounts receivable, net | 158,484 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 175,448 us-gaap_AccountsReceivableNetCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Accrued unbilled revenues, net | 137,374 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 144,124 us-gaap_UnbilledReceivablesCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Other accounts receivable, net | 4,283 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 14,062 us-gaap_AccountsAndOtherReceivablesNetCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Fuel oil stock, at average cost | 106,046 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 134,087 us-gaap_EnergyRelatedInventory / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Materials and supplies, at average cost | 57,250 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 59,044 us-gaap_InventoryRawMaterialsAndSupplies / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Prepayments and other | 66,383 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 52,857 us-gaap_PrepaidExpenseAndOtherAssetsCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Regulatory assets | 71,421 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 69,738 us-gaap_RegulatoryAssetsCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total current assets | 615,003 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 712,185 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Other long-term assets |  |  |  |  |
Regulatory assets | 833,843 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 506,186 us-gaap_RegulatoryAssetsNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Unamortized debt expense | 8,323 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 9,003 us-gaap_UnamortizedDebtIssuanceExpense / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Other | 81,838 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 67,426 us-gaap_OtherAssetsNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total other long-term assets | 924,004 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 582,615 he_AssetsNoncurrentExcludingPropertyPlantAndEquipmentNet / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total assets | 5,590,457 us-gaap_Assets / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 5,087,129 us-gaap_Assets / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Capitalization |  |  |  |  |
Common stock equity | 1,682,144 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,593,564 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,472,136 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,402,841 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |
Cumulative preferred stock-not subject to mandatory redemption | 34,293 us-gaap_PreferredStockValue / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 34,293 us-gaap_PreferredStockValue / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Long-term debt, net | 1,206,546 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,206,545 us-gaap_LongTermDebtNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total capitalization | 2,922,983 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 2,834,402 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Current liabilities |  |  |  |  |
Current portion of long-term debt | 0 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 11,400 us-gaap_LongTermDebtCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Accounts payable | 163,934 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 189,559 us-gaap_AccountsPayableCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Interest and dividends payable | 22,316 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 21,652 he_InterestAndDividendsPayableIncludingDividendsOnPreferredStockOfSubsidiaries / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Taxes accrued | 250,402 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 249,445 us-gaap_TaxesPayableCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Regulatory liabilities | 632 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,916 us-gaap_RegulatoryLiabilityCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Other | 65,146 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 63,881 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total current liabilities | 502,430 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 537,853 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Deferred credits and other liabilities |  |  |  |  |
Deferred income taxes | 602,872 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 507,161 us-gaap_DeferredTaxLiabilitiesNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Regulatory liabilities | 344,217 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 347,383 us-gaap_RegulatoryLiabilityNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Unamortized tax credits | 79,492 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 73,539 us-gaap_AccumulatedDeferredInvestmentTaxCredit / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Defined benefit pension and other postretirement benefit plans liability | 595,395 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 262,162 us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Other | 76,636 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 91,735 us-gaap_OtherLiabilitiesNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total deferred credits and other liabilities | 1,698,612 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 1,281,980 us-gaap_LiabilitiesOtherThanLongtermDebtNoncurrent / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Contributions in aid of construction | 466,432 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 432,894 us-gaap_ContributionsInAidOfConstruction / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Total liabilities and shareholders' equity | 5,590,457 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember | 5,087,129 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_HawaiianElectricCompanyAndSubsidiariesMember |  |  |
Other subsidiaries |  |  |  |  |
Current assets |  |  |  |  |
Cash and cash equivalents | 101 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 101 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 104 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 108 us-gaap_CashAndCashEquivalentsAtCarryingValue / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |
Total current assets | 101 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 101 us-gaap_AssetsCurrent / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |  |  |
Other long-term assets |  |  |  |  |
Total assets | 101 us-gaap_Assets / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 101 us-gaap_Assets / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |  |  |
Capitalization |  |  |  |  |
Common stock equity | 101 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 101 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 104 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 107 us-gaap_StockholdersEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |
Total capitalization | 101 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | 101 us-gaap_CapitalizationLongtermDebtAndEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |  |  |
Current liabilities |  |  |  |  |
Other |  | 0 us-gaap_OtherLiabilitiesCurrent / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |  |  |
Total current liabilities |  | 0 us-gaap_LiabilitiesCurrent / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |  |  |
Deferred credits and other liabilities |  |  |  |  |
Total liabilities and shareholders' equity | $ 101 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember | $ 101 us-gaap_LiabilitiesAndStockholdersEquity / dei_LegalEntityAxis = he_RenewableHawaiiCompanyMember |  |  |

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