Segment financial information - Segment Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment financial information
Revenues	$ 901,873			$ 1,042,197			$ 2,725,795	$ 2,722,872
Income (loss) before income taxes	49,110			79,905			188,781	233,602
Income taxes (benefit)	7,521			17,352			36,915	48,395
Net income (loss)	41,589			62,553			151,866	185,207
Preferred stock dividends of Hawaiian Electric	471			471			1,417	1,417
Net income for common stock	41,118	$ 54,610	$ 54,721	62,082	$ 52,541	$ 69,167	150,449	183,790
Total assets	16,991,818						16,991,818		$ 16,284,244
Revenues from external customers and other sources
Segment financial information
Revenues								2,722,872
Intersegment revenues (eliminations)
Segment financial information
Revenues								0
Electric utility
Segment financial information
Revenues	794,987			955,971			2,419,539	2,483,636
Income (loss) before income taxes	55,415			63,712			175,391	179,771
Income taxes (benefit)	11,456			13,450			38,126	37,967
Net income (loss)	43,959			50,262			137,265	141,804
Preferred stock dividends of Hawaiian Electric	498			498			1,496	1,496
Net income for common stock	43,461			49,764			135,769	140,308
Total assets	7,078,447						7,078,447		6,597,467
Electric utility | Revenues from external customers and other sources
Segment financial information
Revenues								2,483,632
Electric utility | Intersegment revenues (eliminations)
Segment financial information
Revenues								4
Bank
Segment financial information
Revenues	100,974			81,411			291,716	231,850
Income (loss) before income taxes	12,749			27,281			61,511	79,605
Income taxes (benefit)	1,384			6,525			11,380	17,513
Net income (loss)	11,365			20,756			50,131	62,092
Preferred stock dividends of Hawaiian Electric	0			0			0	0
Net income for common stock	11,365			20,756			50,131	62,092
Total assets	9,657,428						9,657,428		9,545,970
Bank | Revenues from external customers and other sources
Segment financial information
Revenues								231,850
Bank | Intersegment revenues (eliminations)
Segment financial information
Revenues								0
Other
Segment financial information
Revenues	5,912			4,815			14,540	7,386
Income (loss) before income taxes	(19,054)			(11,088)			(48,121)	(25,774)
Income taxes (benefit)	(5,319)			(2,623)			(12,591)	(7,085)
Net income (loss)	(13,735)			(8,465)			(35,530)	(18,689)
Preferred stock dividends of Hawaiian Electric	(27)			(27)			(79)	(79)
Net income for common stock	(13,708)			$ (8,438)			(35,451)	(18,610)
Total assets	$ 255,943						$ 255,943		$ 140,807
Other | Revenues from external customers and other sources
Segment financial information
Revenues								7,390
Other | Intersegment revenues (eliminations)
Segment financial information
Revenues								$ (4)