Consolidated Statements of Changes in Common Stock Equity (Parenthetical) - HECO (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net transition asset arising during the period, taxes (tax benefits)			$ 4,172
Prior service credit arising during the period, taxes (tax benefits)	4,422	3,001	921
Net gains (losses) arising during the period, taxes (tax benefits)	(83,147)	(28,431)	41,218
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, taxes (tax benefits)	5,976	2,566	6,861
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes (tax benefits)	64,134	21,336	48,251
Hawaiian Electric Company, Inc. and Subsidiaries
Net transition asset arising during the period, taxes (tax benefits)			4,172
Prior service credit arising during the period, taxes (tax benefits)	4,408	3,001	922
Net gains (losses) arising during the period, taxes (tax benefits)	(74,346)	(27,408)	36,990
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, taxes (tax benefits)	(5,332)	(2,387)	(6,250)
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes (tax benefits)	$ 64,134	$ (21,336)	$ 48,251