Condensed Consolidated Statements of Changes in Shareholders' Equity and Common Stock Equity - USD ($) $ in Thousands	Total	Impact of adoption of ASU No. 2016-13	Balance, January 1, 2020 after adoption of ASU No. 2016-13	Hawaiian Electric Company, Inc. and Subsidiaries	Common stock	Common stock Balance, January 1, 2020 after adoption of ASU No. 2016-13	Common stock Hawaiian Electric Company, Inc. and Subsidiaries	Premium on capital stock Hawaiian Electric Company, Inc. and Subsidiaries	Retained earnings	Retained earnings Impact of adoption of ASU No. 2016-13	Retained earnings Balance, January 1, 2020 after adoption of ASU No. 2016-13	Retained earnings Hawaiian Electric Company, Inc. and Subsidiaries	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Balance, January 1, 2020 after adoption of ASU No. 2016-13	Accumulated other comprehensive income (loss) Hawaiian Electric Company, Inc. and Subsidiaries
Beginning balance (in shares) at Dec. 31, 2019					108,973,000	108,973,000	17,048,000
Beginning balance at Dec. 31, 2019	$ 2,280,260	$ (15,372)	$ 2,264,888	$ 2,047,352	$ 1,678,257	$ 1,678,257	$ 113,678	$ 714,824	$ 622,042	$ (15,372)	$ 606,670	$ 1,220,129	$ (20,039)	$ (20,039)	$ (1,279)
Increase (decrease) in stockholders' equity
Net income for common stock	33,420			23,905					33,420			23,905
Other comprehensive income (loss), net of tax (benefits)	18,212			26									18,212		26
Share-based expenses and other, net (in shares)					172,000
Share-based expenses and other, net	(3,996)				$ (3,996)
Common stock dividends	(36,019)			(26,784)					(36,019)			(26,784)
Ending balance (in shares) at Mar. 31, 2020					109,145,000		17,048,000
Ending balance at Mar. 31, 2020	2,276,505			2,044,499	$ 1,674,261		$ 113,678	714,824	604,071			1,217,250	(1,827)		(1,253)
Beginning balance (in shares) at Dec. 31, 2019					108,973,000	108,973,000	17,048,000
Beginning balance at Dec. 31, 2019	2,280,260	(15,372)	2,264,888	2,047,352	$ 1,678,257	$ 1,678,257	$ 113,678	714,824	622,042	(15,372)	606,670	1,220,129	(20,039)	(20,039)	(1,279)
Increase (decrease) in stockholders' equity
Net income for common stock	82,307			66,234
Other comprehensive income (loss), net of tax (benefits)	17,880			51
Common stock dividends				(53,568)
Ending balance (in shares) at Jun. 30, 2020					109,181,000		17,048,000
Ending balance at Jun. 30, 2020	2,291,398			2,060,069	$ 1,676,616		$ 113,678	714,824	616,941			1,232,795	(2,159)		(1,228)
Beginning balance (in shares) at Dec. 31, 2019					108,973,000	108,973,000	17,048,000
Beginning balance at Dec. 31, 2019	$ 2,280,260	$ (15,372)	$ 2,264,888	2,047,352	$ 1,678,257	$ 1,678,257	$ 113,678	714,824	622,042	$ (15,372)	$ 606,670	1,220,129	(20,039)	$ (20,039)	(1,279)
Ending balance (in shares) at Dec. 31, 2020	109,181,124				109,181,000		17,324,000
Ending balance at Dec. 31, 2020	$ 2,337,502			2,141,918	$ 1,678,368		$ 115,515	746,987	660,398			1,282,335	(1,264)		(2,919)
Increase (decrease) in stockholders' equity
Accounting standards update, extensible enumeration	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance (in shares) at Mar. 31, 2020					109,145,000		17,048,000
Beginning balance at Mar. 31, 2020	$ 2,276,505			2,044,499	$ 1,674,261		$ 113,678	714,824	604,071			1,217,250	(1,827)		(1,253)
Increase (decrease) in stockholders' equity
Net income for common stock	48,887			42,329					48,887			42,329
Other comprehensive income (loss), net of tax (benefits)	(332)			25									(332)		25
Share-based expenses and other, net (in shares)					36,000
Share-based expenses and other, net	2,355				$ 2,355
Common stock dividends	(36,017)			(26,784)					(36,017)			(26,784)
Ending balance (in shares) at Jun. 30, 2020					109,181,000		17,048,000
Ending balance at Jun. 30, 2020	$ 2,291,398			2,060,069	$ 1,676,616		$ 113,678	714,824	616,941			1,232,795	(2,159)		(1,228)
Beginning balance (in shares) at Dec. 31, 2020	109,181,124				109,181,000		17,324,000
Beginning balance at Dec. 31, 2020	$ 2,337,502			2,141,918	$ 1,678,368		$ 115,515	746,987	660,398			1,282,335	(1,264)		(2,919)
Increase (decrease) in stockholders' equity
Net income for common stock	64,358			43,358					64,358			43,358
Other comprehensive income (loss), net of tax (benefits)	(44,016)			34									(44,016)		34
Share-based expenses and other, net (in shares)					100,000
Share-based expenses and other, net	605				$ 605
Common stock dividends	(37,156)			(27,925)					(37,156)			(27,925)
Ending balance (in shares) at Mar. 31, 2021					109,281,000		17,324,000
Ending balance at Mar. 31, 2021	$ 2,321,293			2,157,385	$ 1,678,973		$ 115,515	746,987	687,600			1,297,768	(45,280)		(2,885)
Beginning balance (in shares) at Dec. 31, 2020	109,181,124				109,181,000		17,324,000
Beginning balance at Dec. 31, 2020	$ 2,337,502			2,141,918	$ 1,678,368		$ 115,515	746,987	660,398			1,282,335	(1,264)		(2,919)
Increase (decrease) in stockholders' equity
Net income for common stock	128,230			85,259
Other comprehensive income (loss), net of tax (benefits)	$ (27,544)			69
Common stock dividends				(55,850)
Ending balance (in shares) at Jun. 30, 2021	109,311,034				109,311,000		17,324,000
Ending balance at Jun. 30, 2021	$ 2,367,329			2,171,396	$ 1,681,820		$ 115,515	746,987	714,317			1,311,744	(28,808)		(2,850)
Beginning balance (in shares) at Mar. 31, 2021					109,281,000		17,324,000
Beginning balance at Mar. 31, 2021	2,321,293			2,157,385	$ 1,678,973		$ 115,515	746,987	687,600			1,297,768	(45,280)		(2,885)
Increase (decrease) in stockholders' equity
Net income for common stock	63,872			41,901					63,872			41,901
Other comprehensive income (loss), net of tax (benefits)	16,472			35									16,472		35
Share-based expenses and other, net (in shares)					30,000
Share-based expenses and other, net	2,847				$ 2,847
Common stock dividends	$ (37,155)			(27,925)					(37,155)			(27,925)
Ending balance (in shares) at Jun. 30, 2021	109,311,034				109,311,000		17,324,000
Ending balance at Jun. 30, 2021	$ 2,367,329			$ 2,171,396	$ 1,681,820		$ 115,515	$ 746,987	$ 714,317			$ 1,311,744	$ (28,808)		$ (2,850)