Statements of Consolidated Comprehensive Income (Parenthetical) - HECO (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Less: amortization of net loss, prior service gain and transition obligation included in net periodic benefit cost, taxes (tax benefits)	$ 2,473	$ 631
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes (tax benefits)	2,162	1,431
Hawaiian Electric Company, Inc. and Subsidiaries
Less: amortization of net loss, prior service gain and transition obligation included in net periodic benefit cost, taxes (tax benefits)	2,212	1,448
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes (tax benefits)	$ 2,162	$ 1,431

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