Bank segment - Income statement data (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Noninterest income
Noninterest income	$ 990,338			$ 690,618			$ 2,527,153	$ 1,836,745
Noninterest expense
Income before income taxes	79,905			78,151			233,602	241,291
Income taxes	17,352			14,265			48,395	48,229
Net income attributable to Hawaiian Electric	62,553			63,886			185,207	193,062
Other comprehensive (loss) income, net of tax benefits	(96,012)	$ (87,840)	$ (117,159)	(11,305)	$ 16,472	$ (44,016)	(301,011)	(38,849)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(33,930)			52,110			(117,221)	152,796
American Savings Bank (ASB)
Interest and dividend income
Interest and fees on loans	53,365			49,445			147,499	150,418
Interest and dividends on investment securities	15,052			11,996			43,729	31,709
Total interest and dividend income	68,417			61,441			191,228	182,127
Interest expense
Interest on deposit liabilities	1,704			1,176			3,572	3,919
Interest on other borrowings	1,055			5			1,199	55
Total interest expense	2,759			1,181			4,771	3,974
Net interest income	65,658			60,260			186,457	178,153
Provision for credit losses	(186)			(1,725)			(692)	(22,367)
Net interest income after provision for credit losses	65,844			61,985			187,149	200,520
Noninterest income
Gain on sale of real estate	0			0			1,002	0
Total noninterest income	12,994			14,767			41,624	49,000
Noninterest expense
Compensation and employee benefits	28,597			30,888			83,478	86,595
Occupancy	5,577			5,157			16,996	15,226
Data processing	4,509			4,278			13,144	13,162
Services	2,751			2,272			7,712	7,609
Equipment	2,432			2,373			7,163	6,989
Office supplies, printing and postage	1,123			1,072			3,256	3,094
Marketing	925			995			2,877	2,308
FDIC insurance	914			808			2,613	2,412
Other expense	4,729			3,668			11,929	9,790
Total noninterest expense	51,557			51,511			149,168	147,185
Income before income taxes	27,281			25,241			79,605	102,335
Income taxes	6,525			5,976			17,513	23,230
Net income attributable to Hawaiian Electric	20,756			19,265			62,092	79,105
Other comprehensive (loss) income, net of tax benefits	(98,942)			(11,684)			(310,218)	(40,439)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(78,186)			7,581			(248,126)	38,666
American Savings Bank (ASB) | Fees from other financial services
Noninterest income
Noninterest income	4,763			4,800			15,066	15,337
American Savings Bank (ASB) | Fee income on deposit liabilities
Noninterest income
Noninterest income	4,879			4,262			14,122	12,029
American Savings Bank (ASB) | Fee income on other financial products
Noninterest income
Noninterest income	2,416			2,124			7,663	6,767
American Savings Bank (ASB) | Bank-owned life insurance
Noninterest income
Noninterest income	122			2,026			661	6,211
American Savings Bank (ASB) | Mortgage banking income
Noninterest income
Noninterest income	181			1,272			1,630	7,497
American Savings Bank (ASB) | Gain on sale of investment securities, net
Noninterest income
Noninterest income	0			0			0	528
American Savings Bank (ASB) | Other income, net
Noninterest income
Noninterest income	$ 633			$ 283			$ 1,480	$ 631