Electric utility segment - Condensed consolidating statement of changes in common stock equity (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Increase (decrease) in stockholders' equity
Beginning balance	$ 2,303,642	$ 2,390,884	$ 2,321,293	$ 2,337,502	$ 2,390,884	$ 2,337,502
Net income for common stock	52,541	69,167	63,872	64,358	121,708	128,230
Other comprehensive income, net of taxes	(87,840)	(117,159)	16,472	(44,016)	(204,999)	(27,544)
Common stock dividends	(38,301)	(38,301)	(37,155)	(37,156)
Ending balance	2,233,504	2,303,642	2,367,329	2,321,293	2,233,504	2,367,329
Hawaiian Electric Consolidated
Increase (decrease) in stockholders' equity
Beginning balance	2,276,884	2,261,899	2,157,385	2,141,918	2,261,899	2,141,918
Net income for common stock	44,135	46,409	41,901	43,358	90,544	85,259
Other comprehensive income, net of taxes	51	51	35	34	102	69
Common stock dividends	(31,475)	(31,475)	(27,925)	(27,925)	(62,950)	(55,850)
Ending balance	2,289,595	2,276,884	2,171,396	2,157,385	2,289,595	2,171,396
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric
Increase (decrease) in stockholders' equity
Beginning balance		2,261,899		2,141,918	2,261,899	2,141,918
Net income for common stock	44,135		41,901		90,544	85,259
Other comprehensive income, net of taxes	51		35		102	69
Common stock dividends					(62,950)	(55,850)
Ending balance	2,289,595		2,171,396		2,289,595	2,171,396
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Increase (decrease) in stockholders' equity
Beginning balance		332,900		317,451	332,900	317,451
Net income for common stock	5,658		5,607		13,035	12,299
Other comprehensive income, net of taxes	2		0		2	1
Common stock dividends					(8,200)	(7,300)
Ending balance	337,737		322,451		337,737	322,451
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Increase (decrease) in stockholders' equity
Beginning balance		343,260		309,363	343,260	309,363
Net income for common stock	6,579		5,137		12,863	10,955
Other comprehensive income, net of taxes	1		0		1	0
Common stock dividends					(7,600)	(7,550)
Ending balance	348,524		312,768		348,524	312,768
Hawaiian Electric Consolidated | Reportable Legal Entities | Other subsidiaries
Increase (decrease) in stockholders' equity
Beginning balance		77		77	77	77
Net income for common stock	0		0		0	0
Other comprehensive income, net of taxes	0		0		0	0
Ending balance	77		77		77	77
Hawaiian Electric Consolidated | Consolidating adjustments
Increase (decrease) in stockholders' equity
Beginning balance		$ (676,237)		$ (626,891)	(676,237)	(626,891)
Net income for common stock	(12,237)		(10,744)		(25,898)	(23,254)
Other comprehensive income, net of taxes	(3)		0		(3)	(1)
Common stock dividends					15,800	14,850
Ending balance	$ (686,338)		$ (635,296)		$ (686,338)	$ (635,296)