Electric utility subsidiary - Consolidating financial statements (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Net income for common stock	$ 41,421	$ 40,588	$ 87,348	$ 74,267
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	2,873	5,680	5,686	11,701
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	(2,575)	(4,999)	(5,085)	(10,312)
Other comprehensive income (loss), net of taxes	2,900	(8,305)	4,067	(8,366)
Comprehensive income	44,321	32,283	91,415	65,901
Hawaiian Electric Company
Net income for common stock	34,230	28,693	69,650	53,122
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	2,588	5,016	5,107	10,347
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	(2,575)	(4,999)	(5,085)	(10,312)
Other comprehensive income (loss), net of taxes	13	17	22	35
Comprehensive income	34,243	28,710	69,672	53,157
HELCO
Net income for common stock	4,846	4,880	10,007	9,300
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	292	681	636	1,440
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	(292)	(680)	(636)	(1,441)
Other comprehensive income (loss), net of taxes	0	1	0	(1)
Comprehensive income	4,846	4,881	10,007	9,299
Maui Electric
Net income for common stock	5,013	3,788	8,769	10,353
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	292	622	545	1,279
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	(292)	(623)	(545)	(1,279)
Other comprehensive income (loss), net of taxes	0	(1)	0	0
Comprehensive income	5,013	3,787	8,769	10,353
Other subsidiaries
Net income for common stock	0	(1)	0	(1)
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	0	0	0	0
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	0	0	0	0
Other comprehensive income (loss), net of taxes	0	0	0	0
Comprehensive income	0	(1)	0	(1)
Consolidating adjustments
Net income for common stock	(9,859)	(8,667)	(18,776)	(19,652)
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	(584)	(1,303)	(1,181)	(2,719)
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	584	1,303	1,181	2,720
Other comprehensive income (loss), net of taxes	0	0	0	1
Comprehensive income	(9,859)	(8,667)	(18,776)	(19,651)
HECO Consolidated
Net income for common stock	34,230	28,693	69,650	53,122
Retirement benefit plans:
Less: amortization of transition obligation, prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $1,647, $3,195, $3,252 and $6,590 for the respective periods	2,588	5,016	5,107	10,347
Less: reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $1,641, $3,184, $3,239 and $6,568 for the respective periods	(2,575)	(4,999)	(5,085)	(10,312)
Other comprehensive income (loss), net of taxes	13	17	22	35
Comprehensive income	$ 34,243	$ 28,710	$ 69,672	$ 53,157