Bank segment - Income statement data (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
Noninterest income
Noninterest income	$ 790,988		$ 835,984		$ 1,613,372	$ 1,536,815
Noninterest expense
Income before income taxes	69,367		66,217		139,671	153,697
Income taxes	14,284		13,203		29,394	31,043
Net income attributable to Hawaiian Electric	55,083		53,014		110,277	122,654
Other comprehensive (loss) income, net of tax benefits	(7,609)	$ 20,488	(87,840)	$ (117,159)	12,879	(204,999)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	47,001		(35,299)		122,210	(83,291)
American Savings Bank (ASB)
Interest and dividend income
Interest and fees on loans	67,966		48,129		132,808	94,134
Interest and dividends on investment securities	13,775		14,693		28,412	28,677
Interest and dividend income	81,741		62,822		161,220	122,811
Interest expense
Interest on deposit liabilities	9,661		921		16,498	1,868
Interest on other borrowings	8,852		139		16,573	144
Total interest expense	18,513		1,060		33,071	2,012
Net interest income	63,228		61,762		128,149	120,799
Provision for credit losses	43		2,757		1,218	(506)
Net interest income after provision for credit losses	63,185		59,005		126,931	121,305
Noninterest income
Gain on sale of real estate	495		0		495	1,002
Total noninterest income	15,639		12,502		30,017	28,630
Noninterest expense
Compensation and employee benefits	29,394		27,666		59,598	54,881
Occupancy	5,539		5,467		11,127	11,419
Data processing	5,095		4,484		10,107	8,635
Services	2,689		2,522		5,284	4,961
Equipment	2,957		2,402		5,603	4,731
Office supplies, printing and postage	1,109		1,073		2,274	2,133
Marketing	834		934		1,850	1,952
Other expense	6,152		4,850		12,343	8,899
Noninterest expense	53,769		49,398		108,186	97,611
Income before income taxes	25,055		22,109		48,762	52,324
Income taxes	4,851		4,643		9,996	10,988
Net income attributable to Hawaiian Electric	20,204		17,466		38,766	41,336
Other comprehensive (loss) income, net of tax benefits	(7,210)		(88,835)		11,220	(211,276)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	12,994		(71,369)		49,986	(169,940)
American Savings Bank (ASB) | Fees from other financial services
Noninterest income
Noninterest income	5,009		4,716		9,688	10,303
American Savings Bank (ASB) | Fee income on deposit liabilities
Noninterest income
Noninterest income	4,504		4,552		9,103	9,243
American Savings Bank (ASB) | Fee income on other financial products
Noninterest income
Noninterest income	2,768		2,529		5,512	5,247
American Savings Bank (ASB) | Bank-owned life insurance
Noninterest income
Noninterest income	1,955		(142)		3,380	539
American Savings Bank (ASB) | Mortgage banking income
Noninterest income
Noninterest income	230		372		360	1,449
American Savings Bank (ASB) | Other income, net
Noninterest income
Noninterest income	$ 678		$ 475		$ 1,479	$ 847