Electric utility subsidiary - Consolidating statement of changes in common stock equity (Details 4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Beginning Balance			$ 1,790,573	$ 1,726,406
Net income for common stock	$ 35,018	$ 41,281	66,884	87,068
Other comprehensive income, net of taxes	(3,127)	2,900	931	4,067
Common stock dividends			(65,140)	(62,916)
Ending Balance	1,898,520	1,759,935	1,898,520	1,759,935
Hawaiian Electric Company
Beginning Balance			1,682,144	1,593,564
Net income for common stock	32,841	34,230	59,715	69,650
Other comprehensive income, net of taxes	(15)	13	7	22
Common stock dividends			(45,203)	(44,246)
Common stock issuance expenses			(5)	(3)
Ending Balance	1,696,658	1,618,987	1,696,658	1,618,987
HELCO
Beginning Balance			281,846	274,802
Net income for common stock	4,484	4,846	8,272	10,007
Other comprehensive income, net of taxes	(3)	0	(3)	0
Common stock dividends			(5,010)	(5,813)
Common stock issuance expenses			(1)	(1)
Ending Balance	285,104	278,995	285,104	278,995
Maui Electric
Beginning Balance			256,692	248,771
Net income for common stock	5,140	5,013	9,044	8,769
Other comprehensive income, net of taxes	(3)	0	(3)	0
Common stock dividends			(7,587)	(7,175)
Common stock issuance expenses			0	0
Ending Balance	258,146	250,365	258,146	250,365
Other subsidiaries
Beginning Balance			101	101
Net income for common stock	0	0	0	0
Other comprehensive income, net of taxes	0	0	0	0
Ending Balance	101	101	101	101
Consolidating adjustments
Beginning Balance			(538,639)	(523,674)
Net income for common stock	(9,624)	(9,859)	(17,316)	(18,776)
Other comprehensive income, net of taxes	6	0	6	0
Common stock dividends			12,597	12,988
Common stock issuance expenses			1	1
Ending Balance	(543,351)	(529,461)	(543,351)	(529,461)
HECO Consolidated
Beginning Balance			1,682,144	1,593,564
Net income for common stock	32,841	34,230	59,715	69,650
Other comprehensive income, net of taxes	(15)	13	7	22
Common stock dividends			(45,203)	(44,246)
Common stock issuance expenses			(5)	(3)
Ending Balance	$ 1,696,658	$ 1,618,987	$ 1,696,658	$ 1,618,987