Segment financial information (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	Dec. 31, 2021
Segment financial information
Revenues	$ 895,607		$ 680,257		$ 1,680,675	$ 1,323,203
Income (loss) before income taxes	66,217		82,944		153,697	163,140
Income taxes (benefit)	13,203		18,599		31,043	33,964
Net income attributable to Hawaiian Electric	53,014		64,345		122,654	129,176
Preferred stock dividends of Hawaiian Electric	473		473		946	946
Net income for common stock	52,541	$ 69,167	63,872	$ 64,358	121,708	128,230
Total assets	16,001,743				16,001,743		$ 15,822,637
Revenues from external customers
Segment financial information
Revenues	895,607		680,257		1,680,675	1,323,203
Intersegment revenues (eliminations)
Segment financial information
Revenues	0		0		0	0
Electric utility
Segment financial information
Revenues	818,873		601,879		1,527,665	1,166,743
Income (loss) before income taxes	56,613		53,898		116,059	108,988
Income taxes (benefit)	11,979		11,498		24,517	22,731
Net income attributable to Hawaiian Electric	44,634		42,400		91,542	86,257
Preferred stock dividends of Hawaiian Electric	499		499		998	998
Net income for common stock	44,135		41,901		90,544	85,259
Total assets	6,686,996				6,686,996		6,491,625
Electric utility | Revenues from external customers
Segment financial information
Revenues	818,873		601,869		1,527,661	1,166,724
Electric utility | Intersegment revenues (eliminations)
Segment financial information
Revenues	0		10		4	19
Bank
Segment financial information
Revenues	75,324		77,260		150,439	154,391
Income (loss) before income taxes	22,109		39,992		52,324	77,094
Income taxes (benefit)	4,643		9,708		10,988	17,254
Net income attributable to Hawaiian Electric	17,466		30,284		41,336	59,840
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income for common stock	17,466		30,284		41,336	59,840
Total assets	9,214,865				9,214,865		9,181,603
Bank | Revenues from external customers
Segment financial information
Revenues	75,324		77,260		150,439	154,391
Bank | Intersegment revenues (eliminations)
Segment financial information
Revenues	0		0		0	0
Other
Segment financial information
Revenues	1,410		1,118		2,571	2,069
Income (loss) before income taxes	(12,505)		(10,946)		(14,686)	(22,942)
Income taxes (benefit)	(3,419)		(2,607)		(4,462)	(6,021)
Net income attributable to Hawaiian Electric	(9,086)		(8,339)		(10,224)	(16,921)
Preferred stock dividends of Hawaiian Electric	(26)		(26)		(52)	(52)
Net income for common stock	(9,060)		(8,313)		(10,172)	(16,869)
Total assets	99,882				99,882		$ 149,409
Other | Revenues from external customers
Segment financial information
Revenues	1,410		1,128		2,575	2,088
Other | Intersegment revenues (eliminations)
Segment financial information
Revenues	$ 0		$ (10)		$ (4)	$ (19)