Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Consolidated Statements of Changes in Shareholders' Equity
Cumulative effect of adoption of a standard on other-than-temporary impairment recognition, taxes (tax benefits)				$ 2,497
Net unrealized gains (losses) on securities arising during the period, taxes (tax benefits)		4,343	(789)	8,543
Less: reclassification adjustment for net realized losses included in net income, taxes (tax benefits)		148		(18,882)
Net unrealized holding losses arising during the period, taxes (tax benefits)		(4)	(745)
Less: reclassification adjustment to net income, taxes (tax benefits)		115
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
Common stock dividends (in dollars per share)	$ 0.31	$ 1.24	$ 1.24	$ 1.24
Common stock reserved for future issuance under the HEI Dividend Reinvestment and Stock Purchase Plan (DRIP), the Hawaiian Electric Industries Retirement Savings Plan (HEIRSP), the 1987 Stock Option and Incentive Plan, the HEI 2011 Nonemployee Director Stock Plan, the American Savings Bank, F.S.B. (ASB) 401(k) Plan and the 2010 Executive Incentive Plan. (in shares)	16,900,246	16,900,246