Electric utility segment Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2007
Utility property, plant and equipment
Property, plant and equipment, net	$ 4,148,774	$ 3,865,514
Other long-term assets
Total assets	11,184,161	10,340,044
Capitalization
Common stock equity	1,791,428	1,727,070		$ 1,593,865		$ 1,528,706
Cumulative preferred stock-not subject to mandatory redemption	0	0
Current liabilities
Interest and dividends payable	25,336	26,716
Deferred credits and other liabilities
Deferred income taxes	631,734	529,260
Contributions in aid of construction	466,432	432,894
Total liabilities and shareholders' equity	11,184,161	10,340,044
HECO
Utility property, plant and equipment
Land	43,819	43,407
Plant and equipment	3,782,438	3,558,569
Less accumulated depreciation	(1,253,866)	(1,222,129)
Construction in progress	134,376	124,494
Utility property, plant and equipment, net	2,706,767	2,504,341
Nonutility property, plant and equipment, less accumulated depreciation	4,950	4,953
Property, plant and equipment, net	2,711,717	2,509,294
Investment in wholly-owned subsidiaries, at equity	538,639	523,674
Current assets
Cash and cash equivalents	12,416	61,245		8,265		44,819
Advances to affiliates	16,100	6,839
Customer accounts receivable, net	111,462	121,282
Accrued unbilled revenues, net	103,072	107,752
Other accounts receivable, net	9,980	16,373
Fuel oil stock, at average cost	74,515	99,613
Materials and supplies, at average cost	33,154	37,377
Prepayments and other	44,680	29,798
Regulatory assets	58,550	54,979
Total current assets	463,929	535,258
Other long-term assets
Regulatory assets	623,784	381,346
Unamortized debt expense	5,640	6,051
Other	53,106	42,163
Total other long-term assets	682,530	429,560
Total assets	4,396,815	3,997,786
Capitalization
Common stock equity	1,682,144	1,593,564		1,472,136		1,402,841
Cumulative preferred stock-not subject to mandatory redemption	22,293	22,293
Long-term debt, net	830,546	830,547
Total capitalization	2,534,983	2,446,404
Current liabilities
Current portion of long-term debt	0
Short-term borrowings-affiliate	0	1,000
Accounts payable	122,433	145,062
Interest and dividends payable	15,407	15,190
Taxes accrued	176,339	175,790
Regulatory liabilities	191	1,705
Other	48,282	48,443
Total current liabilities	362,652	387,190
Deferred credits and other liabilities
Deferred income taxes	429,515	359,621
Regulatory liabilities	236,727	235,786
Unamortized tax credits	49,865	44,931
Defined benefit pension and other postretirement benefit plans liability	446,888	202,396
Other	52,446	63,374
Total deferred credits and other liabilities	1,215,441	906,108
Contributions in aid of construction	283,739	258,084
Total liabilities and shareholders' equity	4,396,815	3,997,786
Consolidating adjustments
Utility property, plant and equipment
Nonutility property, plant and equipment, less accumulated depreciation	0
Investment in wholly-owned subsidiaries, at equity	(538,639)	(523,674)
Current assets
Advances to affiliates	(16,100)	(7,839)
Other accounts receivable, net	(8,924)	(9,027)
Prepayments and other	(475)	(1,415)
Total current assets	(25,499)	(18,281)
Other long-term assets
Regulatory assets	(183)
Total other long-term assets	(183)
Total assets	(564,321)	(541,955)
Capitalization
Common stock equity	(538,639)	(523,674)		(497,939)		(516,143)
Total capitalization	(538,639)	(523,674)
Current liabilities
Current portion of long-term debt	0
Short-term borrowings-affiliate	(16,100)	(7,839)
Interest and dividends payable	(11)	(8)
Taxes accrued	(292)	(1,415)
Regulatory liabilities		0
Other	(9,096)	(9,019)
Total current liabilities	(25,499)	(18,281)
Deferred credits and other liabilities
Regulatory liabilities	(183)	0
Total deferred credits and other liabilities	(183)
Total liabilities and shareholders' equity	(564,321)	(541,955)
HELCO
Utility property, plant and equipment
Land	5,464	5,460
Plant and equipment	1,179,032	1,136,923
Less accumulated depreciation	(473,933)	(453,721)
Construction in progress	12,421	7,709
Utility property, plant and equipment, net	722,984	696,371
Nonutility property, plant and equipment, less accumulated depreciation	82	82
Property, plant and equipment, net	723,066	696,453
Current assets
Cash and cash equivalents	612	1,326		5,441		3,383
Advances to affiliates	0	1,000
Customer accounts receivable, net	24,222	28,088
Accrued unbilled revenues, net	15,926	17,100
Other accounts receivable, net	981	4,265
Fuel oil stock, at average cost	13,800	14,178
Materials and supplies, at average cost	6,664	6,883
Prepayments and other	8,611	8,334
Regulatory assets	6,745	6,931
Total current assets	77,561	88,105
Other long-term assets
Regulatory assets	107,454	64,552						$ 12,800
Unamortized debt expense	1,438	1,580
Other	15,366	11,270
Total other long-term assets	124,258	77,402
Total assets	924,885	861,960
Capitalization
Common stock equity	281,846	274,802		268,908		280,468
Cumulative preferred stock-not subject to mandatory redemption	7,000	7,000
Long-term debt, net	190,000	189,998
Total capitalization	478,846	471,800
Current liabilities
Current portion of long-term debt	0	11,400
Short-term borrowings-affiliate	10,500
Accounts payable	23,728	24,383
Interest and dividends payable	3,989	3,885
Taxes accrued	37,548	37,899
Regulatory liabilities		0
Other	9,866	9,033
Total current liabilities	85,631	86,600
Deferred credits and other liabilities
Deferred income taxes	90,119	79,947
Regulatory liabilities	77,707	76,475
Unamortized tax credits	14,902	14,245
Defined benefit pension and other postretirement benefit plans liability	72,547	28,427
Other	10,658	14,703
Total deferred credits and other liabilities	265,933	213,797
Contributions in aid of construction	94,475	89,763
Total liabilities and shareholders' equity	924,885	861,960
MECO
Utility property, plant and equipment
Land	3,016	3,016
Plant and equipment	1,048,012	1,006,383
Less accumulated depreciation	(447,711)	(435,379)
Construction in progress	11,819	11,030
Utility property, plant and equipment, net	615,136	585,050
Nonutility property, plant and equipment, less accumulated depreciation	1,531	1,532
Property, plant and equipment, net	616,667	586,582
Current assets
Cash and cash equivalents	633	153		3,349		496
Advances to affiliates		0
Customer accounts receivable, net	22,800	26,078
Accrued unbilled revenues, net	18,376	19,272
Other accounts receivable, net	2,246	2,451
Fuel oil stock, at average cost	17,731	20,296
Materials and supplies, at average cost	17,432	14,784
Prepayments and other	13,567	16,140
Regulatory assets	6,126	7,828
Total current assets	98,911	107,002
Other long-term assets
Regulatory assets	102,788	60,288
Unamortized debt expense	1,245	1,372
Other	13,366	13,993
Total other long-term assets	117,399	75,653
Total assets	832,977	769,237
Capitalization
Common stock equity	256,692	248,771		228,927		235,568
Cumulative preferred stock-not subject to mandatory redemption	5,000	5,000
Long-term debt, net	186,000	186,000
Total capitalization	447,692	439,771
Current liabilities
Current portion of long-term debt	0
Short-term borrowings-affiliate	5,600	6,839
Accounts payable	17,773	20,114
Interest and dividends payable	2,931	2,585
Taxes accrued	36,807	37,171
Regulatory liabilities	441	211
Other	16,094	15,424
Total current liabilities	79,646	82,344
Deferred credits and other liabilities
Deferred income taxes	83,238	67,593
Regulatory liabilities	29,966	35,122
Unamortized tax credits	14,725	14,363
Defined benefit pension and other postretirement benefit plans liability	75,960	31,339
Other	13,532	13,658
Total deferred credits and other liabilities	217,421	162,075
Contributions in aid of construction	88,218	85,047
Total liabilities and shareholders' equity	832,977	769,237
HECO Consolidated
Utility property, plant and equipment
Land	52,299	51,883
Plant and equipment	6,009,482	5,701,875
Less accumulated depreciation	(2,175,510)	(2,111,229)
Construction in progress	158,616	143,233
Utility property, plant and equipment, net	4,044,887	3,785,762
Nonutility property, plant and equipment, less accumulated depreciation	6,563	6,567
Property, plant and equipment, net	4,051,450	3,792,329
Current assets
Cash and cash equivalents	13,762	62,825	[1]	17,159	[1]	48,806	[1]
Customer accounts receivable, net	158,484	175,448
Accrued unbilled revenues, net	137,374	144,124
Other accounts receivable, net	4,283	14,062
Fuel oil stock, at average cost	106,046	134,087
Materials and supplies, at average cost	57,250	59,044
Prepayments and other	66,383	52,857
Regulatory assets	71,421	69,738
Total current assets	615,003	712,185
Other long-term assets
Regulatory assets	833,843	506,186
Unamortized debt expense	8,323	9,003
Other	81,838	67,426
Total other long-term assets	924,004	582,615
Total assets	5,590,457	5,087,129
Capitalization
Common stock equity	1,682,144	1,593,564		1,472,136		1,402,841
Cumulative preferred stock-not subject to mandatory redemption	34,293	34,293
Long-term debt, net	1,206,546	1,206,545
Total capitalization	2,922,983	2,834,402
Current liabilities
Current portion of long-term debt	0	11,400
Accounts payable	163,934	189,559
Interest and dividends payable	22,316	21,652
Taxes accrued	250,402	249,445
Regulatory liabilities	632	1,916
Other	65,146	63,881
Total current liabilities	502,430	537,853
Deferred credits and other liabilities
Deferred income taxes	602,872	507,161
Regulatory liabilities	344,217	347,383
Unamortized tax credits	79,492	73,539
Defined benefit pension and other postretirement benefit plans liability	595,395	262,162
Other	76,636	91,735
Total deferred credits and other liabilities	1,698,612	1,281,980
Contributions in aid of construction	466,432	432,894
Total liabilities and shareholders' equity	5,590,457	5,087,129
Other subsidiaries
Current assets
Cash and cash equivalents	101	101		104		108
Total current assets	101	101
Other long-term assets
Total assets	101	101
Capitalization
Common stock equity	101	101		$ 104		$ 107
Total capitalization	101	101
Current liabilities
Other		0
Total current liabilities		0
Deferred credits and other liabilities
Total liabilities and shareholders' equity	$ 101	$ 101

[1] As restated - See Note 1, “Summary of significant accounting policies - Revision and restatements of previously issued financial statements.”