Segment financial information - Segment Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment financial information
Revenues	$ 895,685		$ 895,607		$ 1,823,922	$ 1,680,675
Income (loss) before income taxes	69,367		66,217		139,671	153,697
Income taxes (benefit)	14,284		13,203		29,394	31,043
Net income attributable to Hawaiian Electric	55,083		53,014		110,277	122,654
Preferred stock dividends of Hawaiian Electric	473		473		946	946
Net income for common stock	54,610	$ 54,721	52,541	$ 69,167	109,331	121,708
Total assets	16,519,309				16,519,309		$ 16,284,244
Revenues from external customers and other sources
Segment financial information
Revenues						1,680,675
Intersegment revenues (eliminations)
Segment financial information
Revenues						0
Electric utility
Segment financial information
Revenues	794,191		818,873		1,624,552	1,527,665
Income (loss) before income taxes	58,868		56,613		119,976	116,059
Income taxes (benefit)	13,070		11,979		26,670	24,517
Net income attributable to Hawaiian Electric	45,798		44,634		93,306	91,542
Preferred stock dividends of Hawaiian Electric	499		499		998	998
Net income for common stock	45,299		44,135		92,308	90,544
Total assets	6,761,593				6,761,593		6,597,467
Electric utility | Revenues from external customers and other sources
Segment financial information
Revenues						1,527,661
Electric utility | Intersegment revenues (eliminations)
Segment financial information
Revenues						4
Bank
Segment financial information
Revenues	96,885		75,324		190,742	150,439
Income (loss) before income taxes	25,055		22,109		48,762	52,324
Income taxes (benefit)	4,851		4,643		9,996	10,988
Net income attributable to Hawaiian Electric	20,204		17,466		38,766	41,336
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income for common stock	20,204		17,466		38,766	41,336
Total assets	9,620,691				9,620,691		9,545,970
Bank | Revenues from external customers and other sources
Segment financial information
Revenues						150,439
Bank | Intersegment revenues (eliminations)
Segment financial information
Revenues						0
Other
Segment financial information
Revenues	4,609		1,410		8,628	2,571
Income (loss) before income taxes	(14,556)		(12,505)		(29,067)	(14,686)
Income taxes (benefit)	(3,637)		(3,419)		(7,272)	(4,462)
Net income attributable to Hawaiian Electric	(10,919)		(9,086)		(21,795)	(10,224)
Preferred stock dividends of Hawaiian Electric	(26)		(26)		(52)	(52)
Net income for common stock	(10,893)		$ (9,060)		(21,743)	(10,172)
Total assets	$ 137,025				$ 137,025		$ 140,807
Other | Revenues from external customers and other sources
Segment financial information
Revenues						2,575
Other | Intersegment revenues (eliminations)
Segment financial information
Revenues						$ (4)