Electric utility segment - Condensed Consolidating Statement of Changes in Common Stock Equity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Increase (decrease) in stockholders' equity
Beginning balance	$ 1,534,432	$ 1,505,876	$ 1,479,089	$ 1,085,273	$ 2,377,380	$ 2,344,841	$ 1,479,089	$ 2,344,841
Net income (loss) for common stock	30,747	26,085	26,671	(104,402)	(1,295,484)	42,122
Other comprehensive loss, net of tax benefits	(734)	(306)	(460)	39,360	1,594	(9,801)	(1,500)	31,153
Issuance of common stock, net of expenses				575,000
Ending balance	1,563,836	1,534,432	1,505,876	1,577,041	1,085,273	2,377,380	1,563,836	1,577,041
Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance	1,521,617	1,492,244	1,156,955	1,192,842	2,435,282	2,409,110	1,156,955	2,409,110
Net income (loss) for common stock	36,988	39,150	47,816	(82,585)	(1,229,394)	39,221	123,954	(1,272,758)
Other comprehensive loss, net of tax benefits	(24)	(47)	(47)	2	(46)	(49)	(118)	(93)
Issuance of common stock, net of expenses								0
Common stock dividends	(10,000)	(10,000)			(13,000)	(13,000)	(20,000)	(26,000)
Additional paid-in capital		270	287,520				287,790	0
Ending balance	1,548,581	$ 1,521,617	1,492,244	1,110,259	$ 1,192,842	2,435,282	1,548,581	1,110,259
Consolidating adjustments | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			(680,414)			(722,211)	(680,414)	(722,211)
Net income (loss) for common stock							(23,615)	258,633
Other comprehensive loss, net of tax benefits	5			5			36	29
Issuance of common stock, net of expenses								(205,215)
Additional paid-in capital							(686)	(686)
Ending balance	(704,679)			(669,450)			(704,679)	(669,450)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			1,156,955			2,409,110	1,156,955	2,409,110
Net income (loss) for common stock							123,954	(1,272,758)
Other comprehensive loss, net of tax benefits	(24)			2			(118)	(93)
Common stock dividends							(20,000)	(26,000)
Additional paid-in capital							287,790
Ending balance	1,548,581			1,110,259			1,548,581	1,110,259
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			243,964			359,790	243,964	359,790
Net income (loss) for common stock							14,298	(123,080)
Other comprehensive loss, net of tax benefits	2			2			(9)	(5)
Additional paid-in capital							400	400
Ending balance	258,653			237,105			258,653	237,105
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			282,876			362,344	282,876	362,344
Net income (loss) for common stock							5,071	(136,977)
Other comprehensive loss, net of tax benefits	(7)			(7)			(27)	(24)
Issuance of common stock, net of expenses								55,000
Additional paid-in capital							286	286
Ending balance	288,206			280,629			288,206	280,629
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance			$ 153,574			$ 77	153,574	77
Net income (loss) for common stock							4,246	1,424
Other comprehensive loss, net of tax benefits	0			0			0	0
Issuance of common stock, net of expenses								150,215
Ending balance	$ 157,820			$ 151,716			$ 157,820	$ 151,716