Consolidating financial information (Details 4) - HECO (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Balance			$ 1,593,865	$ 1,528,706
Net income (loss) for common stock	40,588	38,800	74,267	77,116
Other comprehensive income (loss), net of taxes	(8,305)	1,550	(8,366)	1,861
Common stock dividends			(61,004)	(59,791)
Balance	1,624,649	1,575,776	1,624,649	1,575,776
HECO
Balance			1,472,136	1,402,841
Net income (loss) for common stock	28,693	29,376	53,122	56,676
Other comprehensive income (loss), net of taxes	17	75	35	152
Common stock dividends			(40,789)	(36,522)
Common stock issue expenses				1
Balance	1,484,504	1,423,148	1,484,504	1,423,148
HELCO
Balance			268,908	280,468
Net income (loss) for common stock	4,880	4,491	9,300	11,102
Other comprehensive income (loss), net of taxes	1	7	(1)	13
Common stock dividends			(7,194)	(6,569)
Balance	271,013	285,014	271,013	285,014
MECO
Balance			228,927	235,568
Net income (loss) for common stock	3,788	3,760	10,353	5,640
Other comprehensive income (loss), net of taxes	(1)	6		12
Common stock dividends			(7,008)	(4,373)
Balance	232,272	236,847	232,272	236,847
Other subsidiaries
Balance			104	107
Net income (loss) for common stock	(1)	(1)	(1)	(2)
Balance	103	105	103	105
Consolidating adjustments
Balance			(497,939)	(516,143)
Net income (loss) for common stock	(8,667)	(8,250)	(19,652)	(16,740)
Other comprehensive income (loss), net of taxes		(13)	1	(25)
Common stock dividends			14,202	10,942
Balance	(503,388)	(521,966)	(503,388)	(521,966)
HECO Consolidated
Balance			1,472,136	1,402,841
Net income (loss) for common stock	28,693	29,376	53,122	56,676
Other comprehensive income (loss), net of taxes	17	75	35	152
Common stock dividends			(40,789)	(36,522)
Common stock issue expenses				1
Balance	$ 1,484,504	$ 1,423,148	$ 1,484,504	$ 1,423,148