Consolidated Statements of Changes in Common Stock Equity - HECO (USD $) In Thousands, except Share data, unless otherwise specified	Total	Hawaiian Electric Company, Inc. and Subsidiaries	Common stock Hawaiian Electric Company, Inc. and Subsidiaries	Premium on capital stock Hawaiian Electric Company, Inc. and Subsidiaries	Retained Earnings Hawaiian Electric Company, Inc. and Subsidiaries	Accumulated other comprehensive income (loss) Hawaiian Electric Company, Inc. and Subsidiaries
Balance at Dec. 31, 2011	$ 1,528,706	$ 1,402,841	$ 94,911	$ 426,921	$ 881,041	$ (32)
Balance (in shares) at Dec. 31, 2011			14,234,000
Increase (decrease) in stockholders' equity
Net income for common stock	38,316	27,300			27,300
Other comprehensive income, net of taxes	311	77				77
Common stock dividends	(29,817)	(18,261)			(18,261)
Balance at Mar. 31, 2012	1,550,855	1,411,957	94,911	426,921	890,080	45
Balance (in shares) at Mar. 31, 2012			14,234,000
Balance at Dec. 31, 2012	1,593,865	1,472,136	97,788	468,045	907,273	(970)
Balance (in shares) at Dec. 31, 2012	97,928,403		14,665,000
Increase (decrease) in stockholders' equity
Net income for common stock	33,679	24,429			24,429
Other comprehensive income, net of taxes	(61)	18				18
Common stock dividends	(30,434)	(20,070)			(20,070)
Balance at Mar. 31, 2013	$ 1,607,265	$ 1,476,513	$ 97,788	$ 468,045	$ 911,632	$ (952)
Balance (in shares) at Mar. 31, 2013	98,471,405		14,665,000