Electric utility segment - Consolidating Statements of Changes in Common Stock Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Increase (decrease) in stockholders' equity
Beginning balance	$ 2,202,499	$ 2,390,884	$ 2,337,502
Net income for common stock	199,238	241,138	246,166
Other comprehensive income (loss), net of taxes	46,678	(283,495)	(51,269)
Common stock dividends	(118,348)	(153,229)	(148,643)
Ending balance	2,344,841	2,202,499	2,390,884
Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance	2,344,170	2,261,899	2,141,918
Net income for common stock	193,952	188,929	177,642
Other comprehensive income (loss), net of taxes	(12)	6,141	(361)
Issuance of common stock, net of expenses		13,101	54,400
Common stock dividends	(129,000)	(125,900)	(111,700)
Ending balance	2,409,110	2,344,170	2,261,899
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance	(701,833)	(676,237)	(626,891)
Net income for common stock	(44,809)	(47,493)	(45,353)
Other comprehensive income (loss), net of taxes	(19)	(657)	(293)
Issuance of common stock, net of expenses		(9,046)	(33,400)
Common stock dividends	24,450	31,600	29,700
Ending balance	(722,211)	(701,833)	(676,237)
Hawaiian Electric
Increase (decrease) in stockholders' equity
Beginning balance	2,202,499
Net income for common stock	199,238	241,138	246,166
Ending balance	2,344,841	2,202,499
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance	2,344,170	2,261,899	2,141,918
Net income for common stock	193,952	188,929	177,642
Other comprehensive income (loss), net of taxes	(12)	6,141	(361)
Issuance of common stock, net of expenses		13,101	54,400
Common stock dividends	(129,000)	(125,900)	(111,700)
Ending balance	2,409,110	2,344,170	2,261,899
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance	344,720	332,900	317,451
Net income for common stock	28,507	21,816	21,180
Other comprehensive income (loss), net of taxes	(12)	381	66
Issuance of common stock, net of expenses		6,023	8,803
Common stock dividends	(13,425)	(16,400)	(14,600)
Ending balance	359,790	344,720	332,900
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance	357,036	343,260	309,363
Net income for common stock	16,302	25,677	24,173
Other comprehensive income (loss), net of taxes	31	276	227
Issuance of common stock, net of expenses		3,023	24,597
Common stock dividends	(11,025)	(15,200)	(15,100)
Ending balance	362,344	357,036	343,260
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance	77	77	77
Ending balance	$ 77	$ 77	$ 77