Electric utility segment (Details 9) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2007
Total assets	$ 10,340,044	$ 10,149,132
Cumulative preferred stock-not subject to mandatory redemption	0	0
Interest and dividends payable	26,716	26,258
Deferred income taxes	529,260	439,329
Contributions in aid of construction	432,894	405,520
Total liabilities and shareholders' equity	10,340,044	10,149,132
HECO
Land	43,407	43,370
Plant and equipment	3,558,569	3,325,862
Less accumulated depreciation	(1,222,129)	(1,185,899)
Construction in progress	124,494	130,143
Net utility plant	2,504,341	2,313,476
Investment in wholly-owned subsidiaries, at equity	523,674	497,939
Cash and cash equivalents	61,245	8,265	44,819	121,019
Advances to affiliates	6,839	9,400
Customer accounts receivable, net	121,282	154,316
Accrued unbilled revenues, net	107,752	100,600
Other accounts receivable, net	16,373	33,313
Fuel oil stock, at average cost	99,613	123,176
Materials and supplies, at average cost	37,377	31,779
Prepayments and other	29,798	21,708
Regulatory assets	54,979	42,675
Total current assets	535,258	525,232
Regulatory assets	381,346	601,451
Unamortized debt expense	6,051	7,042
Other	47,116	46,586
Total other long-term assets	434,513	655,079
Total assets	3,997,786	3,991,726
Common stock equity	1,593,564	1,472,136
Cumulative preferred stock-not subject to mandatory redemption	22,293	22,293
Long-term debt, net	830,547	780,546
Total capitalization	2,446,404	2,274,975
Current portion of long-term debt	0
Short-term borrowings-affiliate	1,000	18,050
Accounts payable	145,062	134,651
Interest and dividends payable	15,190	14,479
Taxes accrued	175,790	174,477
Regulatory liabilities	1,705	1,212
Other	48,443	45,125
Total current liabilities	387,190	387,994
Deferred income taxes	359,621	302,569
Regulatory liabilities	235,786	219,303
Unamortized tax credits	44,931	39,827
Defined benefit pension and other postretirement benefit plans liability	202,396	459,765
Other	63,374	68,783
Total deferred credits and other liabilities	906,108	1,090,247
Contributions in aid of construction	258,084	238,510
Total liabilities and shareholders' equity	3,997,786	3,991,726
Consolidating adjustments
Investment in wholly-owned subsidiaries, at equity	(523,674)	(497,939)
Advances to affiliates	(7,839)	(27,450)
Other accounts receivable, net	(9,027)	(9,275)
Prepayments and other	(1,415)	0
Total current assets	(18,281)	(36,725)
Total assets	(541,955)	(534,664)
Common stock equity	(523,674)	(497,939)
Total capitalization	(523,674)	(497,939)
Current portion of long-term debt	0
Short-term borrowings-affiliate	(7,839)	(27,450)
Interest and dividends payable	(8)	(7)
Taxes accrued	(1,415)	0
Regulatory liabilities		0
Other	(9,019)	(9,268)
Total current liabilities	(18,281)	(36,725)
Total liabilities and shareholders' equity	(541,955)	(534,664)
HELCO
Land	5,460	5,182
Plant and equipment	1,136,923	1,086,048
Less accumulated depreciation	(453,721)	(433,531)
Construction in progress	7,709	12,126
Net utility plant	696,371	669,825
Cash and cash equivalents	1,326	5,441	3,383	1,229
Advances to affiliates	1,000	18,050
Customer accounts receivable, net	28,088	29,772
Accrued unbilled revenues, net	17,100	14,393
Other accounts receivable, net	4,265	1,122
Fuel oil stock, at average cost	14,178	15,485
Materials and supplies, at average cost	6,883	5,336
Prepayments and other	8,334	5,146
Regulatory assets	6,931	4,056
Total current assets	88,105	98,801
Regulatory assets	64,552	109,815			12,800
Unamortized debt expense	1,580	2,066
Other	11,352	9,871
Total other long-term assets	77,484	121,752
Total assets	861,960	890,378
Common stock equity	274,802	268,908
Cumulative preferred stock-not subject to mandatory redemption	7,000	7,000
Long-term debt, net	189,998	201,326
Total capitalization	471,800	477,234
Current portion of long-term debt	11,400
Accounts payable	24,383	27,457
Interest and dividends payable	3,885	4,027
Taxes accrued	37,899	38,778
Regulatory liabilities		0
Other	9,033	10,310
Total current liabilities	86,600	80,572
Deferred income taxes	79,947	68,479
Regulatory liabilities	76,475	67,359
Unamortized tax credits	14,245	13,450
Defined benefit pension and other postretirement benefit plans liability	28,427	80,686
Other	14,703	17,799
Total deferred credits and other liabilities	213,797	247,773
Contributions in aid of construction	89,763	84,799
Total liabilities and shareholders' equity	861,960	890,378
MECO
Land	3,016	3,016
Plant and equipment	1,006,383	952,490
Less accumulated depreciation	(435,379)	(421,359)
Construction in progress	11,030	9,109
Net utility plant	585,050	543,256
Cash and cash equivalents	153	3,349	496	594
Advances to affiliates		0
Customer accounts receivable, net	26,078	26,691
Accrued unbilled revenues, net	19,272	19,305
Other accounts receivable, net	2,451	3,016
Fuel oil stock, at average cost	20,296	22,758
Materials and supplies, at average cost	14,784	13,970
Prepayments and other	16,140	6,011
Regulatory assets	7,828	4,536
Total current assets	107,002	99,636
Regulatory assets	60,288	102,063
Unamortized debt expense	1,372	1,446
Other	15,525	14,848
Total other long-term assets	77,185	118,357
Total assets	769,237	761,249
Common stock equity	248,771	228,927
Cumulative preferred stock-not subject to mandatory redemption	5,000	5,000
Long-term debt, net	186,000	166,000
Total capitalization	439,771	399,927
Current portion of long-term debt	0
Short-term borrowings-affiliate	6,839	9,400
Accounts payable	20,114	24,716
Interest and dividends payable	2,585	2,593
Taxes accrued	37,171	37,811
Regulatory liabilities	211	0
Other	15,424	14,634
Total current liabilities	82,344	89,154
Deferred income taxes	67,593	46,563
Regulatory liabilities	35,122	36,278
Unamortized tax credits	14,363	13,307
Defined benefit pension and other postretirement benefit plans liability	31,339	79,754
Other	13,658	14,055
Total deferred credits and other liabilities	162,075	189,957
Contributions in aid of construction	85,047	82,211
Total liabilities and shareholders' equity	769,237	761,249
HECO Consolidated
Land	51,883	51,568
Plant and equipment	5,701,875	5,364,400
Less accumulated depreciation	(2,111,229)	(2,040,789)
Construction in progress	143,233	151,378
Net utility plant	3,785,762	3,526,557
Cash and cash equivalents	62,825	17,159	48,806	122,936
Customer accounts receivable, net	175,448	210,779
Accrued unbilled revenues, net	144,124	134,298
Other accounts receivable, net	14,062	28,176
Fuel oil stock, at average cost	134,087	161,419
Materials and supplies, at average cost	59,044	51,085
Prepayments and other	52,857	32,865
Regulatory assets	69,738	51,267
Total current assets	712,185	687,048
Regulatory assets	506,186	813,329
Unamortized debt expense	9,003	10,554
Other	73,993	71,305
Total other long-term assets	589,182	895,188
Total assets	5,087,129	5,108,793
Common stock equity	1,593,564	1,472,136
Cumulative preferred stock-not subject to mandatory redemption	34,293	34,293
Long-term debt, net	1,206,545	1,147,872
Total capitalization	2,834,402	2,654,301
Current portion of long-term debt	11,400	0
Accounts payable	189,559	186,824
Interest and dividends payable	21,652	21,092
Taxes accrued	249,445	251,066
Regulatory liabilities	1,916	1,212
Other	63,881	60,801
Total current liabilities	537,853	520,995
Deferred income taxes	507,161	417,611
Regulatory liabilities	347,383	322,940
Unamortized tax credits	73,539	66,584
Defined benefit pension and other postretirement benefit plans liability	262,162	620,205
Other	91,735	100,637
Total deferred credits and other liabilities	1,281,980	1,527,977
Contributions in aid of construction	432,894	405,520
Total liabilities and shareholders' equity	5,087,129	5,108,793
RHI
Cash and cash equivalents	101	104	108	94
Total current assets	101	104
Total assets	101	104
Common stock equity	101	104
Total capitalization	101	104
Other		0
Total current liabilities		0
Total liabilities and shareholders' equity	$ 101	$ 104