Condensed Consolidated Statements of Changes in Common Stock Equity (unaudited) - HECO - USD ($) $ in Thousands	Total	Hawaiian Electric Company, Inc. and Subsidiaries	Common stock	Common stock Hawaiian Electric Company, Inc. and Subsidiaries	Premium on capital stock Hawaiian Electric Company, Inc. and Subsidiaries	Retained earnings (deficit)	Retained earnings (deficit) Hawaiian Electric Company, Inc. and Subsidiaries	Additional paid-in capital Hawaiian Electric Company, Inc. and Subsidiaries	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Hawaiian Electric Company, Inc. and Subsidiaries
Beginning balance (in shares) at Dec. 31, 2023			110,152,000	17,854,000
Beginning balance at Dec. 31, 2023	$ 2,344,841	$ 2,409,110	$ 1,707,471	$ 119,048	$ 810,955	$ 926,720	$ 1,476,258	$ 0	$ (289,350)	$ 2,849
Increase (decrease) in stockholders' equity
Net income (loss) for common stock	42,122	39,221				42,122	39,221
Other comprehensive (loss) income, net of tax benefits	(9,801)	(49)							(9,801)	(49)
Common stock dividends		(13,000)					(13,000)
Ending balance (in shares) at Mar. 31, 2024			110,303,000	17,854,000
Ending balance at Mar. 31, 2024	2,377,380	2,435,282	$ 1,707,689	$ 119,048	810,955	968,842	1,502,479	0	(299,151)	2,800
Beginning balance (in shares) at Dec. 31, 2023			110,152,000	17,854,000
Beginning balance at Dec. 31, 2023	2,344,841	2,409,110	$ 1,707,471	$ 119,048	810,955	926,720	1,476,258	0	(289,350)	2,849
Increase (decrease) in stockholders' equity
Net income (loss) for common stock		(1,272,758)
Other comprehensive (loss) income, net of tax benefits	31,153	(93)
Common stock dividends		(26,000)
Additional paid-in capital		0
Ending balance (in shares) at Sep. 30, 2024			172,466,000	17,854,000
Ending balance at Sep. 30, 2024	1,577,041	1,110,259	$ 2,266,282	$ 119,048	810,955	(431,044)	177,500	0	(258,197)	2,756
Beginning balance (in shares) at Mar. 31, 2024			110,303,000	17,854,000
Beginning balance at Mar. 31, 2024	2,377,380	2,435,282	$ 1,707,689	$ 119,048	810,955	968,842	1,502,479	0	(299,151)	2,800
Increase (decrease) in stockholders' equity
Net income (loss) for common stock	(1,295,484)	(1,229,394)				(1,295,484)	(1,229,394)
Other comprehensive (loss) income, net of tax benefits	1,594	(46)							1,594	(46)
Common stock dividends		(13,000)					(13,000)
Ending balance (in shares) at Jun. 30, 2024			110,303,000	17,854,000
Ending balance at Jun. 30, 2024	1,085,273	1,192,842	$ 1,709,472	$ 119,048	810,955	(326,642)	260,085	0	(297,557)	2,754
Increase (decrease) in stockholders' equity
Net income (loss) for common stock	(104,402)	(82,585)				(104,402)	(82,585)
Other comprehensive (loss) income, net of tax benefits	39,360	2							39,360	2
Ending balance (in shares) at Sep. 30, 2024			172,466,000	17,854,000
Ending balance at Sep. 30, 2024	$ 1,577,041	1,110,259	$ 2,266,282	$ 119,048	810,955	(431,044)	177,500	0	(258,197)	2,756
Beginning balance (in shares) at Dec. 31, 2024	172,465,608		172,466,000	17,854,000
Beginning balance at Dec. 31, 2024	$ 1,479,089	1,156,955	$ 2,264,544	$ 119,048	810,955	(788,916)	223,896	270	3,461	2,786
Increase (decrease) in stockholders' equity
Net income (loss) for common stock	26,671	47,816				26,671	47,816
Other comprehensive (loss) income, net of tax benefits	(460)	(47)							(460)	(47)
Additional paid-in capital		287,520						287,520
Ending balance (in shares) at Mar. 31, 2025			172,494,000	17,854,000
Ending balance at Mar. 31, 2025	$ 1,505,876	1,492,244	$ 2,265,120	$ 119,048	810,955	(762,245)	271,712	287,790	3,001	2,739
Beginning balance (in shares) at Dec. 31, 2024	172,465,608		172,466,000	17,854,000
Beginning balance at Dec. 31, 2024	$ 1,479,089	1,156,955	$ 2,264,544	$ 119,048	810,955	(788,916)	223,896	270	3,461	2,786
Increase (decrease) in stockholders' equity
Net income (loss) for common stock		123,954
Other comprehensive (loss) income, net of tax benefits	$ (1,500)	(118)
Common stock dividends		(20,000)
Additional paid-in capital		287,790
Ending balance (in shares) at Sep. 30, 2025	172,620,476		172,620,000	17,854,000
Ending balance at Sep. 30, 2025	$ 1,563,836	1,548,581	$ 2,267,288	$ 119,048	810,955	(705,413)	327,850	288,060	1,961	2,668
Beginning balance (in shares) at Mar. 31, 2025			172,494,000	17,854,000
Beginning balance at Mar. 31, 2025	1,505,876	1,492,244	$ 2,265,120	$ 119,048	810,955	(762,245)	271,712	287,790	3,001	2,739
Increase (decrease) in stockholders' equity
Net income (loss) for common stock	26,085	39,150				26,085	39,150
Other comprehensive (loss) income, net of tax benefits	(306)	(47)							(306)	(47)
Common stock dividends		(10,000)					(10,000)
Additional paid-in capital		270						270
Ending balance (in shares) at Jun. 30, 2025			172,612,000	17,854,000
Ending balance at Jun. 30, 2025	1,534,432	1,521,617	$ 2,267,897	$ 119,048	810,955	(736,160)	300,862	288,060	2,695	2,692
Increase (decrease) in stockholders' equity
Net income (loss) for common stock	30,747	36,988				30,747	36,988
Other comprehensive (loss) income, net of tax benefits	$ (734)	(24)							(734)	(24)
Common stock dividends		(10,000)					(10,000)
Ending balance (in shares) at Sep. 30, 2025	172,620,476		172,620,000	17,854,000
Ending balance at Sep. 30, 2025	$ 1,563,836	$ 1,548,581	$ 2,267,288	$ 119,048	$ 810,955	$ (705,413)	$ 327,850	$ 288,060	$ 1,961	$ 2,668