Electric utility subsidiary - Consolidating statement of cash flows (Details 5) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities
Net income	[1]	$ 32,339	$ 46,260
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment	[1]	45,865	43,181
Other amortization	[1]	2,371	1,609
Increase in deferred income taxes	[1]	3,828	6,457
Allowance for equity funds used during construction	[1]	(1,413)	(1,609)
Change in cash overdraft	[1]	0	(1,038)
Changes in assets and liabilities
Decrease in fuel oil stock	[1]	20,731	(34,260)
Increase in regulatory assets	[1]	(10,827)	(9,258)
Change in prepaid and accrued income taxes and utility revenue taxes	[1]	(9,461)	(19,474)
Increase (decrease) in defined benefit pension and other postretirement benefit plans liability	[1]	123	(818)
Net cash provided by operating activities	[1]	138,610	43,691
Cash flows from investing activities
Capital expenditures	[1]	(123,527)	(90,442)
Contributions in aid of construction	[1]	9,145	6,958
Cash flows from investing activities-Other	[1]	3,549	343
Net cash used in investing activities	[1]	(152,045)	(98,502)
Cash flows from financing activities
Common stock dividends	[1]	(31,829)	(31,435)
Net increase (decrease) in short-term borrowings with original maturities of three months or less	[1]	(88,472)	30,887
Other	[1]	(3,965)	(3,953)
Net cash provided by financing activities	[1]	130,061	103,895
Net increase (decrease) in cash and cash equivalents	[1]	116,626	49,084
Scenario, Previously Reported
Cash flows from operating activities
Net income			46,400
Adjustments to reconcile net income to net cash provided by operating activities
Other amortization		1,362
Increase in deferred income taxes		15,265	6,298
Changes in assets and liabilities
Change in prepaid and accrued income taxes and utility revenue taxes		(61,397)
Net cash provided by operating activities		76,650	19,421
Cash flows from investing activities
Capital expenditures		(59,011)	(65,829)
Cash flows from investing activities-Other		3,281	0
Net cash used in investing activities		(87,797)	(74,232)
Cash flows from financing activities
Other		(6,253)
Net cash provided by financing activities		127,773
Hawaiian Electric Company
Cash flows from operating activities
Net income		27,144	35,690
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries		(7,717)	(8,942)
Common stock dividends received from subsidiaries		6,324	6,595
Depreciation of property, plant and equipment		29,389	27,301
Other amortization		590	235
Increase in deferred income taxes		12,048	17,123
Change in tax credits, net		2,246	1,741
Allowance for equity funds used during construction		(1,123)	(1,472)
Changes in assets and liabilities
Decrease in accounts receivable		21,703	4,131
Decrease in accrued unbilled revenues		21,726	11,031
Decrease in fuel oil stock		8,654	(35,060)
Increase in materials and supplies		(1,115)	(330)
Increase in regulatory assets		(8,903)	(8,188)
Increase in accounts payable		16,520	17,395
Change in prepaid and accrued income taxes and utility revenue taxes		(52,273)	(39,581)
Increase (decrease) in defined benefit pension and other postretirement benefit plans liability		0	(103)
Change in other assets and liabilities (3)		(8,614)	(11,181)
Net cash provided by operating activities		66,599	16,385
Cash flows from investing activities
Capital expenditures		(92,242)	(67,664)
Contributions in aid of construction		8,121	4,541
Cash flows from investing activities-Other		175	307
Advances from affiliates		3,500	(12,661)
Net cash used in investing activities		(80,446)	(75,477)
Cash flows from financing activities
Common stock dividends		(22,601)	(22,707)
Preferred stock dividends of Hawaiian Electric and subsidiaries		(270)	(270)
Net increase (decrease) in short-term borrowings with original maturities of three months or less		30,000	34,096
Other		(214)	(320)
Net cash provided by financing activities		6,915	10,799
Net increase (decrease) in cash and cash equivalents		(6,932)	(48,293)
Cash and cash equivalents, beginning of period		12,416	61,245
Cash and cash equivalents, end of period		5,484	12,952
Hawaiian Electric Company | Scenario, Previously Reported
Changes in assets and liabilities
Increase in accounts payable		(35,128)	(837)
Change in other assets and liabilities (3)		(8,439)	(10,874)
Cash flows from investing activities
Capital expenditures		(40,594)	(49,432)
Cash flows from investing activities-Other		0	0
HELCO
Cash flows from operating activities
Net income		3,922	5,295
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment		9,313	8,975
Other amortization		500	501
Increase in deferred income taxes		719	862
Change in tax credits, net		200	217
Allowance for equity funds used during construction		(145)	(65)
Changes in assets and liabilities
Decrease in accounts receivable		2,147	2,029
Decrease in accrued unbilled revenues		1,426	(230)
Decrease in fuel oil stock		5,817	1,166
Increase in materials and supplies		75	(387)
Increase in regulatory assets		(1,522)	(881)
Increase in accounts payable		(2,548)	(4,679)
Change in prepaid and accrued income taxes and utility revenue taxes		(1,807)	(2,791)
Increase (decrease) in defined benefit pension and other postretirement benefit plans liability		0	0
Change in other assets and liabilities (3)		203	1,012
Net cash provided by operating activities		18,300	11,024
Cash flows from investing activities
Capital expenditures		(14,902)	(8,883)
Contributions in aid of construction		758	1,121
Cash flows from investing activities-Other		26	29
Advances from affiliates		0	900
Net cash used in investing activities		(14,118)	(6,833)
Cash flows from financing activities
Common stock dividends		(2,505)	(2,941)
Preferred stock dividends of Hawaiian Electric and subsidiaries		(134)	(134)
Net increase (decrease) in short-term borrowings with original maturities of three months or less		(500)	0
Other		(1)	0
Net cash provided by financing activities		(3,140)	(3,075)
Net increase (decrease) in cash and cash equivalents		1,042	1,116
Cash and cash equivalents, beginning of period		612	1,326
Cash and cash equivalents, end of period		1,654	2,442
HELCO | Scenario, Previously Reported
Changes in assets and liabilities
Increase in accounts payable		(9,892)	(6,032)
Change in other assets and liabilities (3)		229	1,041
Cash flows from investing activities
Capital expenditures		(7,558)	(7,530)
Cash flows from investing activities-Other		0	0
Maui Electric
Cash flows from operating activities
Net income		3,999	3,851
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment		5,541	5,327
Other amortization		608	885
Increase in deferred income taxes		2,365	2,359
Change in tax credits, net		130	74
Allowance for equity funds used during construction		(145)	(72)
Change in cash overdraft		0	(1,038)
Changes in assets and liabilities
Decrease in accounts receivable		4,408	2,194
Decrease in accrued unbilled revenues		4,728	1,459
Decrease in fuel oil stock		6,260	(366)
Increase in materials and supplies		(317)	(328)
Increase in regulatory assets		(402)	(189)
Increase in accounts payable		1,408	(4,127)
Change in prepaid and accrued income taxes and utility revenue taxes		(9,616)	(5,154)
Increase (decrease) in defined benefit pension and other postretirement benefit plans liability		110	(102)
Change in other assets and liabilities (3)		(517)	(705)
Net cash provided by operating activities		18,560	4,068
Cash flows from investing activities
Capital expenditures		(11,730)	(12,528)
Contributions in aid of construction		266	1,296
Cash flows from investing activities-Other		42	7
Advances from affiliates		0	0
Net cash used in investing activities		(11,422)	(11,225)
Cash flows from financing activities
Common stock dividends		(3,794)	(3,629)
Preferred stock dividends of Hawaiian Electric and subsidiaries		(95)	(95)
Net increase (decrease) in short-term borrowings with original maturities of three months or less		(3,000)	12,661
Other		(1)	(69)
Net cash provided by financing activities		(6,890)	8,868
Net increase (decrease) in cash and cash equivalents		248	1,711
Cash and cash equivalents, beginning of period		633	153
Cash and cash equivalents, end of period		881	1,864
Maui Electric | Scenario, Previously Reported
Adjustments to reconcile net income to net cash provided by operating activities
Other amortization		(401)
Changes in assets and liabilities
Increase in accounts payable		(4,116)	(9,155)
Change in other assets and liabilities (3)		534	(698)
Cash flows from investing activities
Capital expenditures		(6,206)	(7,500)
Cash flows from investing activities-Other		0	0
Other subsidiaries
Cash flows from operating activities
Net income		0	0
Changes in assets and liabilities
Net cash provided by operating activities		0	0
Cash flows from investing activities
Capital expenditures		0	0
Contributions in aid of construction		0	0
Advances from affiliates		0	0
Net cash used in investing activities		0	0
Cash flows from financing activities
Net increase (decrease) in cash and cash equivalents		0	0
Cash and cash equivalents, beginning of period		101	101
Cash and cash equivalents, end of period		101	101
Consolidating adjustments
Cash flows from operating activities
Net income		(7,692)	(8,917)
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries		7,692	8,917
Common stock dividends received from subsidiaries		(6,299)	(6,570)
Changes in assets and liabilities
Decrease in accounts receivable		846	450
Change in other assets and liabilities (3)		(846)	(450)
Net cash provided by operating activities		(6,299)	(6,570)
Cash flows from investing activities
Capital expenditures		0	0
Contributions in aid of construction		0	0
Advances from affiliates		(3,500)	11,761
Net cash used in investing activities		(3,500)	11,761
Cash flows from financing activities
Common stock dividends		6,299	6,570
Net increase (decrease) in short-term borrowings with original maturities of three months or less		3,500	(11,761)
Net cash provided by financing activities		9,799	(5,191)
Net increase (decrease) in cash and cash equivalents		0	0
Cash and cash equivalents, beginning of period		0	0
Cash and cash equivalents, end of period		0	0
Consolidating adjustments | Scenario, Previously Reported
Changes in assets and liabilities
Change in other assets and liabilities (3)		(846)	(450)
HECO Consolidated
Cash flows from operating activities
Net income	[1]	27,373	35,919
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries		(25)	(25)
Common stock dividends received from subsidiaries		25	25
Depreciation of property, plant and equipment	[1]	44,243	41,603
Other amortization	[1]	1,698	1,621
Increase in deferred income taxes	[1]	15,132	20,344
Change in tax credits, net	[1]	2,576	2,032
Allowance for equity funds used during construction	[1]	(1,413)	(1,609)
Change in cash overdraft	[1]	0	(1,038)
Changes in assets and liabilities
Decrease in accounts receivable	[1]	29,104	8,804
Decrease in accrued unbilled revenues	[1]	27,880	12,260
Decrease in fuel oil stock	[1]	20,731	(34,260)
Increase in materials and supplies	[1]	(1,357)	(1,045)
Increase in regulatory assets	[1]	(10,827)	(9,258)
Increase in accounts payable	[1]	15,380	8,589
Change in prepaid and accrued income taxes and utility revenue taxes	[1]	(63,696)	(47,526)
Increase (decrease) in defined benefit pension and other postretirement benefit plans liability	[1]	110	(205)
Change in other assets and liabilities (3)		(9,774)	(11,324)
Net cash provided by operating activities	[1]	97,160	24,907
Cash flows from investing activities
Capital expenditures	[1]	(118,874)	(89,075)
Contributions in aid of construction	[1]	9,145	6,958
Cash flows from investing activities-Other		243	343
Advances from affiliates		0	0
Net cash used in investing activities	[1]	(109,486)	(81,774)
Cash flows from financing activities
Common stock dividends	[1]	(22,601)	(22,707)
Preferred stock dividends of Hawaiian Electric and subsidiaries	[1]	(499)	(499)
Net increase (decrease) in short-term borrowings with original maturities of three months or less	[1]	30,000	34,996
Other	[1]	(216)	(389)
Net cash provided by financing activities	[1]	6,684	11,401
Net increase (decrease) in cash and cash equivalents	[1]	(5,642)	(45,466)
Cash and cash equivalents, beginning of period	[1]	13,762	62,825
Cash and cash equivalents, end of period	[1]	8,120	17,359
HECO Consolidated | Scenario, Previously Reported
Adjustments to reconcile net income to net cash provided by operating activities
Other amortization		689
Changes in assets and liabilities
Increase in accounts payable		(49,136)	(16,024)
Change in other assets and liabilities (3)		(8,522)	(10,981)
Net cash provided by operating activities		32,887	637
Cash flows from investing activities
Capital expenditures		(54,358)	(64,462)
Cash flows from investing activities-Other		0	0
Net cash used in investing activities		$ (45,213)	$ (57,504)

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