Electric utility segment - Consolidating Statements of Changes in Common Stock Equity (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Increase (decrease) in stockholders' equity
Beginning balance				$ 2,344,841				$ 2,202,499	$ 2,344,841	$ 2,202,499	$ 2,390,884
Net income for common stock	$ (68,245)	$ (104,402)	$ (1,295,484)	42,122	$ 48,789	$ 41,118	$ 54,610	54,721	(1,426,009)	199,238	241,138
Other comprehensive income (loss), net of taxes									3,184	46,678	(283,495)
Common stock dividends										(118,348)	(153,229)
Additional paid-in capital									270
Ending balance	1,479,089				2,344,841				1,479,089	2,344,841	2,202,499
Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance				2,409,110				2,344,170	2,409,110	2,344,170	2,261,899
Net income for common stock									(1,226,362)	193,952	188,929
Other comprehensive income (loss), net of taxes									(63)	(12)	6,141
Issuance of common stock, net of expenses									0		13,101
Common stock dividends									(26,000)	(129,000)	(125,900)
Additional paid-in capital									270
Ending balance	1,156,955				2,409,110				1,156,955	2,409,110	2,344,170
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance				(722,211)				(701,833)	(722,211)	(701,833)	(676,237)
Net income for common stock									248,004	(44,809)	(47,493)
Other comprehensive income (loss), net of taxes									(77)	(19)	(657)
Issuance of common stock, net of expenses									(205,215)		(9,046)
Common stock dividends										24,450	31,600
Additional paid-in capital									(915)
Ending balance	(680,414)				(722,211)				(680,414)	(722,211)	(701,833)
Hawaiian Electric
Increase (decrease) in stockholders' equity
Beginning balance				2,344,841					2,344,841
Net income for common stock									(1,426,009)	199,238	241,138
Ending balance	1,479,089				2,344,841				1,479,089	2,344,841
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance				2,409,110				2,344,170	2,409,110	2,344,170	2,261,899
Net income for common stock									(1,226,362)	193,952	188,929
Other comprehensive income (loss), net of taxes									(63)	(12)	6,141
Issuance of common stock, net of expenses											13,101
Common stock dividends									(26,000)	(129,000)	(125,900)
Additional paid-in capital									270
Ending balance	1,156,955				2,409,110				1,156,955	2,409,110	2,344,170
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance				359,790				344,720	359,790	344,720	332,900
Net income for common stock									(116,414)	28,507	21,816
Other comprehensive income (loss), net of taxes									54	(12)	381
Issuance of common stock, net of expenses											6,023
Common stock dividends										(13,425)	(16,400)
Additional paid-in capital									534
Ending balance	243,964				359,790				243,964	359,790	344,720
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance				362,344				357,036	362,344	357,036	343,260
Net income for common stock									(134,872)	16,302	25,677
Other comprehensive income (loss), net of taxes									23	31	276
Issuance of common stock, net of expenses									55,000		3,023
Common stock dividends										(11,025)	(15,200)
Additional paid-in capital									381
Ending balance	282,876				362,344				282,876	362,344	357,036
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance				$ 77				$ 77	77	77	77
Net income for common stock									3,282
Other comprehensive income (loss), net of taxes									0
Issuance of common stock, net of expenses									150,215
Ending balance	$ 153,574				$ 77				$ 153,574	$ 77	$ 77