Consolidated Statements of Comprehensive Income (Parenthetical) - HECO (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Less: amortization of net loss, prior service gain and transition obligation included in net periodic benefit cost, tax benefits	$ 2,443	$ 1,405	$ 7,321	$ 3,513
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	2,129	1,074	6,386	3,875
Hawaiian Electric Company, Inc. and Subsidiaries
Less: amortization of net loss, prior service gain and transition obligation included in net periodic benefit cost, tax benefits	2,178	1,150	6,532	3,999
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	$ 2,129	$ 1,074	$ 6,386	$ 3,875

Tax effect on adjustment out of other comprehensive income for actuarial gains or losses, prior service gains or losses, and net transition asset or obligation recognized as a component of net periodic benefit cost during the period.

No definition available.

Name:	he_OtherComprehensiveIncomeReclassificationOfDefinedBenefitPlansNetGainLossPriorServiceGainLossAndReclassificationOfDefinedBenefitPlanNetTransitionAssetObligationRecognizedInNetPeriodicBenefitCostTax
Namespace Prefix:	he_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration