Quarterly information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 790,040	$ 867,096	$ 798,657	$ 783,749	$ 832,503	$ 829,168	$ 794,567	$ 782,232	$ 3,239,542	$ 3,238,470		$ 3,374,995
Operating income	67,241	91,102	82,275	88,306	78,349	88,038	80,207	68,825	328,924	315,419		284,196
Net income	33,630	48,286	41,894	46,400	39,486	48,707	41,061	34,152	170,210	163,406	[1]	140,548	[1]
Net income for common stock	$ 33,157	$ 47,815	$ 41,421	$ 45,927	$ 39,013	$ 48,236	$ 40,588	$ 33,679	$ 168,320	$ 161,516		$ 138,658
Basic earnings per common share (in dollars per share)	$ 0.32	$ 0.47	$ 0.41	$ 0.45	$ 0.39	$ 0.49	$ 0.41	$ 0.34	$ 1.65	$ 1.63		$ 1.43
Diluted earnings per common share (in dollars per share)	0.32	0.46	0.41	0.45	0.39	0.48	0.41	0.34	1.64	1.62		1.42
Dividends per common share (in dollars per share)	0.31	0.31	0.31	0.31	0.31	0.31	0.31	0.31	1.24	1.24		$ 1.24
Market price per common share
High end of range (in dollars per share)	35.00	26.89	25.65	26.80	27.15	27.24	28.30	27.92	35.00	28.30
Low end of range (in dollars per share)	$ 26.04	$ 22.71	$ 23.04	$ 24.39	$ 24.51	$ 24.12	$ 23.84	$ 25.50	$ 22.71	$ 23.84
Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 725,267	$ 803,565	$ 738,429	$ 720,062	$ 770,152	$ 764,054	$ 728,525	$ 717,441	$ 2,987,323	$ 2,980,172		$ 3,109,439
Operating income	58,878	76,156	70,068	70,666	65,564	69,853	58,975	51,121	275,768	245,513		213,012
Net income	29,611	39,377	34,729	35,919	32,489	38,315	29,192	24,928	139,636	124,924	[1]	101,271	[1]
Net income for common stock	$ 29,112	$ 38,879	$ 34,230	$ 35,420	$ 31,990	$ 37,817	$ 28,693	$ 24,429	$ 137,641	$ 122,929		$ 99,276

[1] As restated - See Note 1, “Summary of significant accounting policies - Revision and restatements of previously issued financial statements.”