Electric utility subsidiary - Consolidating financial statements (Details 3) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Utility plant, at cost
Total property, plant and equipment, net	$ 3,980,096	$ 3,865,514
Other long-term assets
Total assets	10,617,143	10,340,044
Capitalization
Common stock equity	1,760,879	1,727,070	1,624,649	1,593,865
Cumulative preferred stock — not subject to mandatory redemption	0	0
Current liabilities
Interest and preferred dividends payable	25,315	26,716
Deferred credits and other liabilities
Deferred income taxes	579,222	529,260
Contributions in aid of construction	442,379	432,894
Total liabilities and shareholders’ equity	10,617,143	10,340,044
Hawaiian Electric Company
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	3
Utility plant, at cost
Land	43,530	43,407
Plant and equipment	3,655,958	3,558,569
Less accumulated depreciation	(1,239,994)	(1,222,129)
Construction in progress	139,149	124,494
Utility property, plant and equipment, net	2,598,643	2,504,341
Nonutility property, plant and equipment, less accumulated depreciation	4,951	4,953
Total property, plant and equipment, net	2,603,594	2,509,294
Investment in wholly owned subsidiaries, at equity	529,461	523,674
Current assets
Cash and cash equivalents	8,106	61,245	4,914	8,265
Advances to affiliates	23,600	6,839
Customer accounts receivable, net	122,400	121,282
Accrued unbilled revenues, net	106,694	107,752
Other accounts receivable, net	20,095	16,373
Fuel oil stock, at average cost	123,070	99,613
Materials and supplies, at average cost	37,606	37,377
Prepayments and other	43,057	29,798
Regulatory assets	64,210	54,979
Total current assets	548,838	535,258
Other long-term assets
Regulatory assets	380,993	381,346
Unamortized debt expense	6,020	6,051
Other	42,662	42,163
Total other long-term assets	429,675	429,560
Total assets	4,111,568	3,997,786
Capitalization
Common stock equity	1,618,987	1,593,564	1,484,504	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	2,471,826	2,446,404
Current liabilities
Short-term borrowings from non-affiliates	102,989
Short-term borrowings from affiliate	0	1,000
Accounts payable	114,803	145,062
Interest and preferred dividends payable	14,827	15,190
Taxes accrued	150,709	175,790
Regulatory liabilities	453	1,705
Other	49,370	48,443
Total current liabilities	433,151	387,190
Deferred credits and other liabilities
Deferred income taxes	399,826	359,621
Regulatory liabilities	240,533	235,786
Unamortized tax credits	48,386	44,931
Defined benefit pension and other postretirement benefit plans liability	195,599	202,396
Other	57,397	63,374
Total deferred credits and other liabilities	941,741	906,108
Contributions in aid of construction	264,850	258,084
Total liabilities and shareholders’ equity	4,111,568	3,997,786
HELCO
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(1)
Utility plant, at cost
Land	5,464	5,460
Plant and equipment	1,147,841	1,136,923
Less accumulated depreciation	(465,966)	(453,721)
Construction in progress	14,669	7,709
Utility property, plant and equipment, net	702,008	696,371
Nonutility property, plant and equipment, less accumulated depreciation	82	82
Total property, plant and equipment, net	702,090	696,453
Current assets
Cash and cash equivalents	1,754	1,326	3,401	5,441
Advances to affiliates	0	1,000
Customer accounts receivable, net	27,465	28,088
Accrued unbilled revenues, net	17,452	17,100
Other accounts receivable, net	6,415	4,265
Fuel oil stock, at average cost	12,517	14,178
Materials and supplies, at average cost	7,129	6,883
Prepayments and other	7,185	8,334
Regulatory assets	6,947	6,931
Total current assets	86,864	88,105
Other long-term assets
Regulatory assets	64,159	64,552
Unamortized debt expense	1,532	1,580
Other	11,565	11,270
Total other long-term assets	77,256	77,402
Total assets	866,210	861,960
Capitalization
Common stock equity	278,995	274,802	271,013	268,908
Cumulative preferred stock — not subject to mandatory redemption	7,000	7,000
Long-term debt, net	189,999	189,998
Total capitalization	475,994	471,800
Current liabilities
Current portion of long-term debt	11,400	11,400
Short-term borrowings from affiliate	3,400
Accounts payable	18,434	24,383
Interest and preferred dividends payable	4,177	3,885
Taxes accrued	33,058	37,899
Regulatory liabilities	0	0
Other	9,391	9,033
Total current liabilities	79,860	86,600
Deferred credits and other liabilities
Deferred income taxes	84,147	79,947
Regulatory liabilities	79,990	76,475
Unamortized tax credits	14,668	14,245
Defined benefit pension and other postretirement benefit plans liability	26,952	28,427
Other	13,821	14,703
Total deferred credits and other liabilities	219,578	213,797
Contributions in aid of construction	90,778	89,763
Total liabilities and shareholders’ equity	866,210	861,960
Maui Electric
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	0
Utility plant, at cost
Land	3,016	3,016
Plant and equipment	1,026,924	1,006,383
Less accumulated depreciation	(444,953)	(435,379)
Construction in progress	14,462	11,030
Utility property, plant and equipment, net	599,449	585,050
Nonutility property, plant and equipment, less accumulated depreciation	1,531	1,532
Total property, plant and equipment, net	600,980	586,582
Current assets
Cash and cash equivalents	2,759	153	199	3,349
Customer accounts receivable, net	25,769	26,078
Accrued unbilled revenues, net	17,723	19,272
Other accounts receivable, net	2,052	2,451
Fuel oil stock, at average cost	25,706	20,296
Materials and supplies, at average cost	16,144	14,784
Prepayments and other	11,900	16,140
Regulatory assets	7,788	7,828
Total current assets	109,841	107,002
Other long-term assets
Regulatory assets	58,548	60,288
Unamortized debt expense	1,353	1,372
Other	14,199	13,993
Total other long-term assets	74,100	75,653
Total assets	784,921	769,237
Capitalization
Common stock equity	250,365	248,771	232,272	228,927
Cumulative preferred stock — not subject to mandatory redemption	5,000	5,000
Long-term debt, net	186,000	186,000
Total capitalization	441,365	439,771
Current liabilities
Short-term borrowings from affiliate	20,200	6,839
Accounts payable	20,506	20,114
Interest and preferred dividends payable	2,755	2,585
Taxes accrued	32,858	37,171
Regulatory liabilities	336	211
Other	15,447	15,424
Total current liabilities	92,102	82,344
Deferred credits and other liabilities
Deferred income taxes	73,083	67,593
Regulatory liabilities	33,668	35,122
Unamortized tax credits	14,659	14,363
Defined benefit pension and other postretirement benefit plans liability	30,234	31,339
Other	13,059	13,658
Total deferred credits and other liabilities	164,703	162,075
Contributions in aid of construction	86,751	85,047
Total liabilities and shareholders’ equity	784,921	769,237
Other subsidiaries
Current assets
Cash and cash equivalents	101	101	103	104
Total current assets	101	101
Other long-term assets
Total assets	101	101
Capitalization
Common stock equity	101	101	103	104
Total capitalization	101	101
Deferred credits and other liabilities
Total liabilities and shareholders’ equity	101	101
Consolidating adjustments
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	(1)
Utility plant, at cost
Investment in wholly owned subsidiaries, at equity	(529,461)	(523,674)
Current assets
Cash and cash equivalents			0	0
Advances to affiliates	(23,600)	(7,839)
Other accounts receivable, net	(9,647)	(9,027)
Prepayments and other	(251)	(1,415)
Total current assets	(33,498)	(18,281)
Other long-term assets
Total assets	(562,959)	(541,955)
Capitalization
Common stock equity	(529,461)	(523,674)	(503,388)	(497,939)
Total capitalization	(529,461)	(523,674)
Current liabilities
Short-term borrowings from affiliate	(23,600)	(7,839)
Interest and preferred dividends payable	(8)	(8)
Taxes accrued	(251)	(1,415)
Regulatory liabilities	0	0
Other	(9,639)	(9,019)
Total current liabilities	(33,498)	(18,281)
Deferred credits and other liabilities
Total liabilities and shareholders’ equity	(562,959)	(541,955)
HECO Consolidated
Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs	3
Utility plant, at cost
Land	52,010	51,883
Plant and equipment	5,830,723	5,701,875
Less accumulated depreciation	(2,150,913)	(2,111,229)
Construction in progress	168,280	143,233
Utility property, plant and equipment, net	3,900,100	3,785,762
Nonutility property, plant and equipment, less accumulated depreciation	6,564	6,567
Total property, plant and equipment, net	3,906,664	3,792,329
Current assets
Cash and cash equivalents	12,720	62,825	8,617	17,159
Customer accounts receivable, net	175,634	175,448
Accrued unbilled revenues, net	141,869	144,124
Other accounts receivable, net	18,915	14,062
Fuel oil stock, at average cost	161,293	134,087
Materials and supplies, at average cost	60,879	59,044
Prepayments and other	61,891	52,857
Regulatory assets	78,945	69,738
Total current assets	712,146	712,185
Other long-term assets
Regulatory assets	503,700	506,186
Unamortized debt expense	8,905	9,003
Other	68,426	67,426
Total other long-term assets	581,031	582,615
Total assets	5,199,841	5,087,129
Capitalization
Common stock equity	1,618,987	1,593,564	1,484,504	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	2,859,825	2,834,402
Current liabilities
Current portion of long-term debt	11,400	11,400
Short-term borrowings from non-affiliates	102,989	0
Accounts payable	153,743	189,559
Interest and preferred dividends payable	21,751	21,652
Taxes accrued	216,374	249,445
Regulatory liabilities	789	1,916
Other	64,569	63,881
Total current liabilities	571,615	537,853
Deferred credits and other liabilities
Deferred income taxes	557,056	507,161
Regulatory liabilities	354,191	347,383
Unamortized tax credits	77,713	73,539
Defined benefit pension and other postretirement benefit plans liability	252,785	262,162
Other	84,277	91,735
Total deferred credits and other liabilities	1,326,022	1,281,980
Contributions in aid of construction	442,379	432,894
Total liabilities and shareholders’ equity	$ 5,199,841	$ 5,087,129