Electric utility segment - Condensed Consolidating Statement of Changes in Common Stock Equity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Increase (decrease) in stockholders' equity
Beginning balance	$ 1,085,273	$ 2,377,380	$ 2,344,841	$ 2,249,377	$ 2,237,955	$ 2,202,499	$ 2,344,841	$ 2,202,499
Net income (loss) for common stock	(104,402)	(1,295,484)	42,122	41,118	54,610	54,721	(1,357,764)	150,449
Other comprehensive loss, net of taxes	39,360	1,594	(9,801)	(34,875)	(7,609)	20,488	31,153	(21,996)
Common stock dividends				(39,455)	(39,447)	(39,446)
Issuance of common stock, net of expenses	575,000
Ending balance	1,577,041	1,085,273	2,377,380	2,224,354	2,249,377	2,237,955	1,577,041	2,224,354
Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance	1,192,842	2,435,282	2,409,110	2,371,889	2,358,884	2,344,170	2,409,110	2,344,170
Net income (loss) for common stock	(82,585)	(1,229,394)	39,221	43,461	45,299	47,009	(1,272,758)	135,769
Other comprehensive loss, net of taxes	2	(46)	(49)	(77)	(44)	(45)	(93)	(166)
Common stock dividends		(13,000)	(13,000)	(32,250)	(32,250)	(32,250)	(26,000)	(96,750)
Additional paid-in capital							0
Issuance of common stock, net of expenses							0
Ending balance	1,110,259	$ 1,192,842	2,435,282	2,383,023	$ 2,371,889	2,358,884	1,110,259	2,383,023
Consolidating adjustments | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			(722,211)			(701,833)	(722,211)	(701,833)
Net income (loss) for common stock	18,558			(3,005)			258,633	(25,960)
Other comprehensive loss, net of taxes	5			9			29	32
Common stock dividends								24,450
Additional paid-in capital							(686)
Issuance of common stock, net of expenses							(205,215)
Ending balance	(669,450)			(703,311)			(669,450)	(703,311)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			2,409,110			2,344,170	2,409,110	2,344,170
Net income (loss) for common stock	(82,585)			43,461			(1,272,758)	135,769
Other comprehensive loss, net of taxes	2			(77)			(93)	(166)
Common stock dividends							(26,000)	(96,750)
Ending balance	1,110,259			2,383,023			1,110,259	2,383,023
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			359,790			344,720	359,790	344,720
Net income (loss) for common stock	(7,175)			7,419			(123,080)	20,884
Other comprehensive loss, net of taxes	2			(1)			(5)	(9)
Common stock dividends								(13,425)
Additional paid-in capital							400
Ending balance	237,105			352,170			237,105	352,170
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			362,344			357,036	362,344	357,036
Net income (loss) for common stock	(12,807)			(4,414)			(136,977)	5,076
Other comprehensive loss, net of taxes	(7)			(8)			(24)	(23)
Common stock dividends								(11,025)
Additional paid-in capital							286
Issuance of common stock, net of expenses							55,000
Ending balance	280,629			351,064			280,629	351,064
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			$ 77			$ 77	77	77
Net income (loss) for common stock	1,424			0			1,424	0
Other comprehensive loss, net of taxes	0			0			0	0
Issuance of common stock, net of expenses							150,215
Ending balance	$ 151,716			$ 77			$ 151,716	$ 77