Electric utility segment - Consolidating statement of changes in common stock equity (Details 4) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Beginning Balance			$ 1,790,573	$ 1,726,406
Net income for common stock	$ 50,673	$ 47,808	117,557	134,876
Other comprehensive income, net of taxes	4,430	(1,311)	5,361	2,756
Common stock dividends			(98,452)	(94,711)
Ending Balance	1,921,001	1,800,457	1,921,001	1,800,457
Hawaiian Electric Company
Beginning Balance			1,682,144	1,593,564
Net income for common stock	43,006	38,879	102,721	108,529
Other comprehensive income, net of taxes	4	10	11	32
Common stock dividends			(67,804)	(66,369)
Common stock issuance expenses			(8)	(5)
Ending Balance	1,717,064	1,635,751	1,717,064	1,635,751
HELCO
Beginning Balance			281,846	274,802
Net income for common stock	4,189	3,301	12,461	13,308
Other comprehensive income, net of taxes	(1)	(2)	(4)	(2)
Common stock dividends			(7,515)	(8,720)
Common stock issuance expenses			0	0
Ending Balance	286,788	279,388	286,788	279,388
Maui Electric
Beginning Balance			256,692	248,771
Net income for common stock	7,669	6,499	16,713	15,268
Other comprehensive income, net of taxes	(1)	0	(4)	0
Common stock dividends			(11,382)	(10,762)
Common stock issuance expenses			(1)	0
Ending Balance	262,018	253,277	262,018	253,277
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	(11,858)	(9,800)	(29,174)	(28,576)
Other comprehensive income, net of taxes	2	2	8	2
Common stock dividends			18,897	19,482
Common stock issuance expenses			1	0
Ending Balance	(548,907)	(532,766)	(548,907)	(532,766)
HECO Consolidated
Beginning Balance			1,682,144	1,593,564
Net income for common stock	43,006	38,879	102,721	108,529
Other comprehensive income, net of taxes	4	10	11	32
Common stock dividends			(67,804)	(66,369)
Common stock issuance expenses			(8)	(5)
Ending Balance	$ 1,717,064	$ 1,635,751	$ 1,717,064	$ 1,635,751