Electric utility subsidiary - Consolidating balance sheet (Details 3) - USD ($) $ in Thousands		Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Utility plant, at cost
Total property, plant and equipment, net		$ 4,190,835	$ 4,148,774
Other long-term assets
Total assets		11,273,447	11,185,142
Capitalization
Common stock equity		1,897,909	1,790,573	$ 1,745,124	$ 1,726,406
Cumulative preferred stock — not subject to mandatory redemption		0	0
Current liabilities
Interest and preferred dividends payable		25,225	25,336
Deferred credits and other liabilities
Deferred income taxes		640,778	633,570
Contributions in aid of construction		474,385	466,432
Total liabilities and shareholders’ equity		11,273,447	11,185,142
Hawaiian Electric Company
Utility plant, at cost
Land		43,542	43,819
Plant and equipment		3,826,826	3,782,438
Less accumulated depreciation		(1,256,950)	(1,253,866)
Construction in progress		135,984	134,376
Utility property, plant and equipment, net		2,749,402	2,706,767
Nonutility property, plant and equipment, less accumulated depreciation		4,949	4,950
Total property, plant and equipment, net		2,754,351	2,711,717
Investment in wholly owned subsidiaries, at equity		540,032	538,639
Current assets
Cash and cash equivalents		5,484	12,416	12,952	61,245
Advances to affiliates		12,600	16,100
Customer accounts receivable, net		86,157	111,462
Accrued unbilled revenues, net		81,346	103,072
Other accounts receivable, net		13,582	9,980
Fuel oil stock, at average cost		65,861	74,515
Materials and supplies, at average cost		34,269	33,154
Prepayments and other		31,970	44,680
Regulatory assets		85,353	58,550
Total current assets		416,622	463,929
Other long-term assets
Regulatory assets		598,535	623,784
Unamortized debt expense		5,621	5,640
Other		53,370	53,106
Total other long-term assets		657,526	682,530
Total assets		4,368,531	4,396,815
Capitalization
Common stock equity		1,686,434	1,682,144	1,606,283	1,593,564
Cumulative preferred stock — not subject to mandatory redemption		22,293	22,293
Long-term debt, net		830,546	830,546
Total capitalization		2,539,273	2,534,983
Current liabilities
Short-term borrowings from non-affiliates		30,000
Short-term borrowings from affiliate		0	0
Accounts payable		106,975	122,433
Interest and preferred dividends payable		16,678	15,407
Taxes accrued		126,742	176,339
Regulatory liabilities		681	191
Other		49,389	48,282
Total current liabilities		330,465	362,652
Deferred credits and other liabilities
Deferred income taxes		423,151	429,515
Regulatory liabilities		240,749	236,727
Unamortized tax credits		52,093	49,865
Defined benefit pension and other postretirement benefit plans liability		443,249	446,888
Other		48,044	52,446
Total deferred credits and other liabilities		1,207,286	1,215,441
Contributions in aid of construction		291,507	283,739
Total liabilities and shareholders’ equity		4,368,531	4,396,815
HELCO
Utility plant, at cost
Land		5,464	5,464
Plant and equipment		1,182,567	1,179,032
Less accumulated depreciation		(478,692)	(473,933)
Construction in progress		14,947	12,421
Utility property, plant and equipment, net		724,286	722,984
Nonutility property, plant and equipment, less accumulated depreciation		82	82
Total property, plant and equipment, net		724,368	723,066
Current assets
Cash and cash equivalents		1,654	612	2,442	1,326
Advances to affiliates		0	0
Customer accounts receivable, net		21,485	24,222
Accrued unbilled revenues, net		14,500	15,926
Other accounts receivable, net		1,571	981
Fuel oil stock, at average cost		7,983	13,800
Materials and supplies, at average cost		6,589	6,664
Prepayments and other		230	8,611
Regulatory assets		9,359	6,745
Total current assets		63,371	77,561
Other long-term assets
Regulatory assets		104,663	107,454
Unamortized debt expense		1,396	1,438
Other		15,689	15,366
Total other long-term assets		121,748	124,258
Total assets		909,487	924,885
Capitalization
Common stock equity		283,129	281,846	277,022	274,802
Cumulative preferred stock — not subject to mandatory redemption		7,000	7,000
Long-term debt, net		190,000	190,000
Total capitalization		480,129	478,846
Current liabilities
Current portion of long-term debt		0
Short-term borrowings from affiliate		10,000	10,500
Accounts payable		14,988	23,728
Interest and preferred dividends payable		3,560	3,989
Taxes accrued		30,060	37,548
Regulatory liabilities		0	0
Other		10,126	9,866
Total current liabilities		68,734	85,631
Deferred credits and other liabilities
Deferred income taxes		89,923	90,119
Regulatory liabilities		79,504	77,707
Unamortized tax credits		15,096	14,902
Defined benefit pension and other postretirement benefit plans liability		68,989	72,547
Other		12,664	10,658
Total deferred credits and other liabilities		266,176	265,933
Contributions in aid of construction		94,448	94,475
Total liabilities and shareholders’ equity		909,487	924,885
Maui Electric
Utility plant, at cost
Land		3,016	3,016
Plant and equipment		1,057,130	1,048,012
Less accumulated depreciation		(453,448)	(447,711)
Construction in progress		13,920	11,819
Utility property, plant and equipment, net		620,618	615,136
Nonutility property, plant and equipment, less accumulated depreciation		1,531	1,531
Total property, plant and equipment, net		622,149	616,667
Current assets
Cash and cash equivalents		881	633	1,864	153
Customer accounts receivable, net		17,353	22,800
Accrued unbilled revenues, net		13,648	18,376
Other accounts receivable, net		3,285	2,246
Fuel oil stock, at average cost		11,471	17,731
Materials and supplies, at average cost		17,749	17,432
Prepayments and other		12,534	13,567
Regulatory assets		8,033	6,126
Total current assets		84,954	98,911
Other long-term assets
Regulatory assets		99,749	102,788
Unamortized debt expense		1,199	1,245
Other		13,214	13,366
Total other long-term assets		114,162	117,399
Total assets		821,265	832,977
Capitalization
Common stock equity		256,802	256,692	248,897	248,771
Cumulative preferred stock — not subject to mandatory redemption		5,000	5,000
Long-term debt, net		186,000	186,000
Total capitalization		447,802	447,692
Current liabilities
Short-term borrowings from affiliate		2,600	5,600
Accounts payable		16,546	17,773
Interest and preferred dividends payable		4,029	2,931
Taxes accrued		27,449	36,807
Regulatory liabilities		493	441
Other		16,234	16,094
Total current liabilities		67,351	79,646
Deferred credits and other liabilities
Deferred income taxes		83,910	83,238
Regulatory liabilities		30,388	29,966
Unamortized tax credits		14,848	14,725
Defined benefit pension and other postretirement benefit plans liability		74,927	75,960
Other		13,609	13,532
Total deferred credits and other liabilities		217,682	217,421
Contributions in aid of construction		88,430	88,218
Total liabilities and shareholders’ equity		821,265	832,977
Other subsidiaries
Current assets
Cash and cash equivalents		101	101	101	101
Total current assets		101	101
Other long-term assets
Total assets		101	101
Capitalization
Common stock equity		101	101	101	101
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		(540,032)	(538,639)
Current assets
Cash and cash equivalents		0	0	0	0
Advances to affiliates		(12,600)	(16,100)
Other accounts receivable, net		(9,770)	(8,924)
Prepayments and other		(1,379)	(475)
Total current assets		(23,749)	(25,499)
Other long-term assets
Regulatory assets		(103)	(183)
Total other long-term assets		(103)	(183)
Total assets		(563,884)	(564,321)
Capitalization
Common stock equity		(540,032)	(538,639)	(526,020)	(523,674)
Total capitalization		(540,032)	(538,639)
Current liabilities
Short-term borrowings from affiliate		(12,600)	(16,100)
Interest and preferred dividends payable		(10)	(11)
Taxes accrued		(1,379)	(292)
Regulatory liabilities		0	0
Other		(9,760)	(9,096)
Total current liabilities		(23,749)	(25,499)
Deferred credits and other liabilities
Regulatory liabilities		(103)	(183)
Total deferred credits and other liabilities			(183)
Total liabilities and shareholders’ equity		(563,884)	(564,321)
HECO Consolidated
Utility plant, at cost
Land		52,022	52,299
Plant and equipment		6,066,523	6,009,482
Less accumulated depreciation		(2,189,090)	(2,175,510)
Construction in progress		164,851	158,616
Utility property, plant and equipment, net		4,094,306	4,044,887
Nonutility property, plant and equipment, less accumulated depreciation		6,562	6,563
Total property, plant and equipment, net		4,100,868	4,051,450
Current assets
Cash and cash equivalents	[1]	8,120	13,762	17,359	62,825
Customer accounts receivable, net		124,995	158,484
Accrued unbilled revenues, net		109,494	137,374
Other accounts receivable, net		8,668	4,283
Fuel oil stock, at average cost		85,315	106,046
Materials and supplies, at average cost		58,607	57,250
Prepayments and other		43,355	66,383
Regulatory assets		102,745	71,421
Total current assets		541,299	615,003
Other long-term assets
Regulatory assets		802,844	833,843
Unamortized debt expense		8,216	8,323
Other		82,273	81,838
Total other long-term assets		893,333	924,004
Total assets		5,535,500	5,590,457
Capitalization
Common stock equity		1,686,434	1,682,144	$ 1,606,283	$ 1,593,564
Cumulative preferred stock — not subject to mandatory redemption		34,293	34,293
Long-term debt, net		1,206,546	1,206,546
Total capitalization		2,927,273	2,922,983
Current liabilities
Current portion of long-term debt		0
Short-term borrowings from non-affiliates		30,000	0
Accounts payable		138,509	163,934
Interest and preferred dividends payable		24,257	22,316
Taxes accrued		182,872	250,402
Regulatory liabilities		1,174	632
Other		65,989	65,146
Total current liabilities		442,801	502,430
Deferred credits and other liabilities
Deferred income taxes		596,984	602,872
Regulatory liabilities		350,538	344,217
Unamortized tax credits		82,037	79,492
Defined benefit pension and other postretirement benefit plans liability		587,165	595,395
Other		74,317	76,636
Total deferred credits and other liabilities		1,691,041	1,698,612
Contributions in aid of construction		474,385	466,432
Total liabilities and shareholders’ equity		$ 5,535,500	$ 5,590,457

[1] As restated - See Note 1, “Basis of presentation - Restatement of previously issued financial statements.”