Electric utility subsidiary - Consolidating statement of changes in common stock equity (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Balance	$ 1,790,573us-gaap_StockholdersEquity	$ 1,726,406us-gaap_StockholdersEquity
Net income for common stock	31,866	45,787
Other comprehensive income, net of taxes	4,058	1,167
Common stock dividends	(31,840)us-gaap_DividendsCommonStockCash	(31,448)us-gaap_DividendsCommonStockCash
Balance	1,897,909us-gaap_StockholdersEquity	1,745,124us-gaap_StockholdersEquity
Hawaiian Electric Company
Balance	1,682,144	1,593,564
Net income for common stock	26,874	35,420
Other comprehensive income, net of taxes	22	9
Common stock dividends	(22,601)	(22,707)
Common stock issuance expenses	(5)	(3)
Balance	1,686,434	1,606,283
HELCO
Balance	281,846	274,802
Net income for common stock	3,788	5,161
Other comprehensive income, net of taxes	0	0
Common stock dividends	(2,505)	(2,941)
Common stock issuance expenses	0	0
Balance	283,129	277,022
Maui Electric
Balance	256,692	248,771
Net income for common stock	3,904	3,756
Other comprehensive income, net of taxes	0	0
Common stock dividends	(3,794)	(3,629)
Common stock issuance expenses	0	(1)
Balance	256,802	248,897
Other subsidiaries
Balance	101	101
Net income for common stock	0	0
Other comprehensive income, net of taxes	0	0
Balance	101	101
Consolidating adjustments
Balance	(538,639)	(523,674)
Net income for common stock	(7,692)	(8,917)
Other comprehensive income, net of taxes	0	0
Common stock dividends	6,299	6,570
Common stock issuance expenses	0	1
Balance	(540,032)	(526,020)
HECO Consolidated
Balance	1,682,144	1,593,564
Net income for common stock	26,874	35,420
Other comprehensive income, net of taxes	22	9
Common stock dividends	(22,601)	(22,707)
Common stock issuance expenses	(5)	(3)
Balance	$ 1,686,434	$ 1,606,283

Amount of decrease in additional paid in capital (APIC) resulting from direct costs associated with issuing stock. Includes, but is not limited to, legal and accounting fees and direct costs associated with stock issues under a shelf registration.

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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