Electric utility subsidiary - Consolidating financial statements (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Utility plant, at cost
Total property, plant and equipment, net	$ 3,908,392	$ 3,865,514
Other long-term assets
Total assets	10,458,070	10,340,044
Capitalization
Common stock equity	1,745,928	1,727,070	1,607,265	1,593,865
Cumulative preferred stock — not subject to mandatory redemption	0	0
Current liabilities
Interest and preferred dividends payable	28,520	26,716
Deferred credits and other liabilities
Deferred income taxes	538,321	529,260
Contributions in aid of construction	438,020	432,894
Total liabilities and shareholders’ equity	10,458,070	10,340,044
Hawaiian Electric Company
Utility plant, at cost
Land	43,367	43,407
Plant and equipment	3,606,787	3,558,569
Less accumulated depreciation	(1,234,520)	(1,222,129)
Construction in progress	127,187	124,494
Utility property, plant and equipment, net	2,542,821	2,504,341
Nonutility property, plant and equipment, less accumulated depreciation	4,953	4,953
Total property, plant and equipment, net	2,547,774	2,509,294
Investment in wholly owned subsidiaries, at equity	526,020	523,674
Current assets
Cash and cash equivalents	12,952	61,245	32,661	8,265
Advances to affiliates	19,500	6,839
Customer accounts receivable, net	114,517	121,282
Accrued unbilled revenues, net	96,721	107,752
Other accounts receivable, net	19,007	16,373
Fuel oil stock, at average cost	134,673	99,613
Materials and supplies, at average cost	37,707	37,377
Prepayments and other	17,931	29,798
Regulatory assets	62,643	54,979
Total current assets	515,651	535,258
Other long-term assets
Regulatory assets	378,608	381,346
Unamortized debt expense	6,195	6,051
Other	42,110	42,163
Total other long-term assets	426,913	429,560
Total assets	4,016,358	3,997,786
Capitalization
Common stock equity	1,606,283	1,593,564	1,476,513	1,472,136
Cumulative preferred stock — not subject to mandatory redemption	22,293	22,293
Long-term debt, net	830,546	830,547
Total capitalization	2,459,122	2,446,404
Current liabilities
Short-term borrowings from non-affiliates	34,996
Short-term borrowings from affiliate	100	1,000
Accounts payable	151,818	145,062
Interest and preferred dividends payable	16,400	15,190
Taxes accrued	133,801	175,790
Regulatory liabilities	1,135	1,705
Other	47,374	48,443
Total current liabilities	385,624	387,190
Deferred credits and other liabilities
Deferred income taxes	365,668	359,621
Regulatory liabilities	236,468	235,786
Unamortized tax credits	46,658	44,931
Defined benefit pension and other postretirement benefit plans liability	199,070	202,396
Other	61,762	63,374
Total deferred credits and other liabilities	909,626	906,108
Contributions in aid of construction	261,986	258,084
Total liabilities and shareholders’ equity	4,016,358	3,997,786
HELCO
Utility plant, at cost
Land	5,462	5,460
Plant and equipment	1,141,789	1,136,923
Less accumulated depreciation	(459,712)	(453,721)
Construction in progress	9,657	7,709
Utility property, plant and equipment, net	697,196	696,371
Nonutility property, plant and equipment, less accumulated depreciation	82	82
Total property, plant and equipment, net	697,278	696,453
Current assets
Cash and cash equivalents	2,442	1,326	2,770	5,441
Advances to affiliates	100	1,000
Customer accounts receivable, net	26,004	28,088
Accrued unbilled revenues, net	17,330	17,100
Other accounts receivable, net	4,320	4,265
Fuel oil stock, at average cost	13,012	14,178
Materials and supplies, at average cost	7,270	6,883
Prepayments and other	2,707	8,334
Regulatory assets	6,958	6,931
Total current assets	80,143	88,105
Other long-term assets
Regulatory assets	64,379	64,552
Unamortized debt expense	1,533	1,580
Other	11,351	11,270
Total other long-term assets	77,263	77,402
Total assets	854,684	861,960
Capitalization
Common stock equity	277,022	274,802	269,716	268,908
Cumulative preferred stock — not subject to mandatory redemption	7,000	7,000
Long-term debt, net	189,999	189,998
Total capitalization	474,021	471,800
Current liabilities
Current portion of long-term debt	11,400	11,400
Accounts payable	18,953	24,383
Interest and preferred dividends payable	3,882	3,885
Taxes accrued	31,545	37,899
Regulatory liabilities	0	0
Other	9,950	9,033
Total current liabilities	75,730	86,600
Deferred credits and other liabilities
Deferred income taxes	80,454	79,947
Regulatory liabilities	78,142	76,475
Unamortized tax credits	14,457	14,245
Defined benefit pension and other postretirement benefit plans liability	27,750	28,427
Other	13,985	14,703
Total deferred credits and other liabilities	214,788	213,797
Contributions in aid of construction	90,145	89,763
Total liabilities and shareholders’ equity	854,684	861,960
Maui Electric
Utility plant, at cost
Land	3,016	3,016
Plant and equipment	1,014,323	1,006,383
Less accumulated depreciation	(440,228)	(435,379)
Construction in progress	11,758	11,030
Utility property, plant and equipment, net	588,869	585,050
Nonutility property, plant and equipment, less accumulated depreciation	1,531	1,532
Total property, plant and equipment, net	590,400	586,582
Current assets
Cash and cash equivalents	1,864	153	1,405	3,349
Customer accounts receivable, net	23,495	26,078
Accrued unbilled revenues, net	17,813	19,272
Other accounts receivable, net	2,840	2,451
Fuel oil stock, at average cost	20,662	20,296
Materials and supplies, at average cost	15,112	14,784
Prepayments and other	12,958	16,140
Regulatory assets	7,854	7,828
Total current assets	102,598	107,002
Other long-term assets
Regulatory assets	59,521	60,288
Unamortized debt expense	1,396	1,372
Other	13,925	13,993
Total other long-term assets	74,842	75,653
Total assets	767,840	769,237
Capitalization
Common stock equity	248,897	248,771	232,051	228,927
Cumulative preferred stock — not subject to mandatory redemption	5,000	5,000
Long-term debt, net	186,000	186,000
Total capitalization	439,897	439,771
Current liabilities
Short-term borrowings from affiliate	19,500	6,839
Accounts payable	12,055	20,114
Interest and preferred dividends payable	3,826	2,585
Taxes accrued	29,685	37,171
Regulatory liabilities	302	211
Other	14,621	15,424
Total current liabilities	79,989	82,344
Deferred credits and other liabilities
Deferred income taxes	68,919	67,593
Regulatory liabilities	34,869	35,122
Unamortized tax credits	14,429	14,363
Defined benefit pension and other postretirement benefit plans liability	30,781	31,339
Other	13,067	13,658
Total deferred credits and other liabilities	162,065	162,075
Contributions in aid of construction	85,889	85,047
Total liabilities and shareholders’ equity	767,840	769,237
Other subsidiaries
Current assets
Cash and cash equivalents	101	101	104	104
Total current assets	101	101
Other long-term assets
Total assets	101	101
Capitalization
Common stock equity	101	101	104	104
Total capitalization	101	101
Deferred credits and other liabilities
Total liabilities and shareholders’ equity	101	101
Consolidating adjustments
Utility plant, at cost
Investment in wholly owned subsidiaries, at equity	(526,020)	(523,674)
Current assets
Advances to affiliates	(19,600)	(7,839)
Other accounts receivable, net	(9,477)	(9,027)
Prepayments and other	(1,297)	(1,415)
Total current assets	(30,374)	(18,281)
Other long-term assets
Total assets	(556,394)	(541,955)
Capitalization
Common stock equity	(526,020)	(523,674)	(501,871)	(497,939)
Total capitalization	(526,020)	(523,674)
Current liabilities
Short-term borrowings from affiliate	(19,600)	(7,839)
Interest and preferred dividends payable	(8)	(8)
Taxes accrued	(1,297)	(1,415)
Regulatory liabilities	0	0
Other	(9,469)	(9,019)
Total current liabilities	(30,374)	(18,281)
Deferred credits and other liabilities
Total liabilities and shareholders’ equity	(556,394)	(541,955)
HECO Consolidated
Utility plant, at cost
Land	51,845	51,883
Plant and equipment	5,762,899	5,701,875
Less accumulated depreciation	(2,134,460)	(2,111,229)
Construction in progress	148,602	143,233
Utility property, plant and equipment, net	3,828,886	3,785,762
Nonutility property, plant and equipment, less accumulated depreciation	6,566	6,567
Total property, plant and equipment, net	3,835,452	3,792,329
Current assets
Cash and cash equivalents	17,359	62,825	36,940	17,159
Customer accounts receivable, net	164,016	175,448
Accrued unbilled revenues, net	131,864	144,124
Other accounts receivable, net	16,690	14,062
Fuel oil stock, at average cost	168,347	134,087
Materials and supplies, at average cost	60,089	59,044
Prepayments and other	32,299	52,857
Regulatory assets	77,455	69,738
Total current assets	668,119	712,185
Other long-term assets
Regulatory assets	502,508	506,186
Unamortized debt expense	9,124	9,003
Other	67,386	67,426
Total other long-term assets	579,018	582,615
Total assets	5,082,589	5,087,129
Capitalization
Common stock equity	1,606,283	1,593,564	1,476,513	1,472,136
Cumulative preferred stock — not subject to mandatory redemption	34,293	34,293
Long-term debt, net	1,206,545	1,206,545
Total capitalization	2,847,121	2,834,402
Current liabilities
Current portion of long-term debt	11,400	11,400
Short-term borrowings from non-affiliates	34,996	0
Accounts payable	182,826	189,559
Interest and preferred dividends payable	24,100	21,652
Taxes accrued	193,734	249,445
Regulatory liabilities	1,437	1,916
Other	62,476	63,881
Total current liabilities	510,969	537,853
Deferred credits and other liabilities
Deferred income taxes	515,041	507,161
Regulatory liabilities	349,479	347,383
Unamortized tax credits	75,544	73,539
Defined benefit pension and other postretirement benefit plans liability	257,601	262,162
Other	88,814	91,735
Total deferred credits and other liabilities	1,286,479	1,281,980
Contributions in aid of construction	438,020	432,894
Total liabilities and shareholders’ equity	$ 5,082,589	$ 5,087,129