Electric utility subsidiary - Consolidating financial statements (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Balance			$ 1,727,070	$ 1,593,865
Net income for common stock	47,815	48,236	135,163	122,503
Other comprehensive income (loss), net of taxes	(1,311)	(897)	2,756	(9,263)
Common stock dividends			(94,711)	(91,739)
Balance	1,801,408	1,655,465	1,801,408	1,655,465
Hawaiian Electric Company
Balance			1,593,564	1,472,136
Net income for common stock	38,879	37,817	108,529	90,939
Other comprehensive income (loss), net of taxes	10	17	32	52
Common stock dividends			(66,369)	(61,183)
Common stock issuance expenses			(5)
Balance	1,635,751	1,501,944	1,635,751	1,501,944
HELCO
Balance			274,802	268,908
Net income for common stock	3,301	5,444	13,308	14,744
Other comprehensive income (loss), net of taxes	(2)	(1)	(2)	(2)
Common stock dividends			(8,720)	(10,790)
Common stock issuance expenses			0
Balance	279,388	272,860	279,388	272,860
Maui Electric
Balance			248,771	228,927
Net income for common stock	6,499	5,351	15,268	15,704
Other comprehensive income (loss), net of taxes	0	0	0	0
Common stock dividends			(10,762)	(10,513)
Common stock issuance expenses			0
Balance	253,277	234,118	253,277	234,118
Other subsidiaries
Balance			101	104
Net income for common stock	0	(1)	0	(2)
Other comprehensive income (loss), net of taxes	0	0	0	0
Balance	101	102	101	102
Consolidating adjustments
Balance			(523,674)	(497,939)
Net income for common stock	(9,800)	(10,794)	(28,576)	(30,446)
Other comprehensive income (loss), net of taxes	2	1	2	2
Common stock dividends			19,482	21,303
Common stock issuance expenses			0
Balance	(532,766)	(507,080)	(532,766)	(507,080)
HECO Consolidated
Balance			1,593,564	1,472,136
Net income for common stock	38,879	37,817	108,529	90,939
Other comprehensive income (loss), net of taxes	10	17	32	52
Common stock dividends			(66,369)	(61,183)
Common stock issuance expenses			(5)
Balance	$ 1,635,751	$ 1,501,944	$ 1,635,751	$ 1,501,944