Bank segment (HEI only) - Statements of Income Data (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Interest expense
Interest on deposit liabilities	$ 16,830	$ 13,991	$ 9,660
Total interest expense	109,339	104,216	91,128
Noninterest income
Revenues	2,622,025	2,614,831
Noninterest expense
Income before income taxes	271,409	254,461	276,580
Income taxes	51,637	50,797	109,393
Current period other comprehensive income (loss) and reclassifications, net of taxes	30,571	(8,669)	(1,372)
Comprehensive income	248,453	193,105	163,925
American Savings Bank (ASB)
Interest and dividend income
Interest and fees on loans	233,632	220,463	207,255
Interest and dividends on investment securities	32,922	37,762	28,823
Total interest and dividend income	266,554	258,225	236,078
Interest expense
Interest on deposit liabilities	16,830	13,991	9,660
Interest on other borrowings	1,610	1,548	2,496
Total interest expense	18,440	15,539	12,156
Net interest income	248,114	242,686	223,922
Provision for loan losses	23,480	14,745	10,901
Net interest income after provision for loan losses	224,634	227,941	213,021
Noninterest income
Gain on sale of properties	10,762	0	0
Gains on sale of investment securities, net	653	0	0
Total noninterest income	72,778	56,050	61,562
Noninterest expense
Compensation and employee benefits	103,009	98,387	94,931
Occupancy	21,272	17,073	16,699
Data processing	15,306	14,268	13,280
Services	10,239	10,847	10,994
Equipment	8,760	7,186	7,232
Office supplies, printing and postage	5,512	6,134	6,182
Marketing	4,490	3,567	3,501
FDIC insurance	1,204	2,713	2,904
Other expense	15,586	17,238	20,144
Total noninterest expense	185,378	177,413	175,867
Income before income taxes	112,034	106,578	98,716
Income taxes	23,061	24,069	31,719
Net income attributable to Hawaiian Electric	88,973	82,509	66,997
Current period other comprehensive income (loss) and reclassifications, net of taxes	29,406	(7,119)	(3,139)
Comprehensive income	118,379	75,390	63,858
American Savings Bank (ASB) | Fees from other financial services
Noninterest income
Revenues	19,275	18,937	22,796
American Savings Bank (ASB) | Fee income on deposit liabilities
Noninterest income
Revenues	20,877	21,311	22,204
American Savings Bank (ASB) | Fee income on other financial products
Noninterest income
Revenues	6,507	7,052	7,205
American Savings Bank (ASB) | Bank-owned life insurance
Noninterest income
Revenues	7,687	5,057	5,539
American Savings Bank (ASB) | Mortgage banking income
Noninterest income
Revenues	4,943	1,493	2,201
American Savings Bank (ASB) | Other income, net
Noninterest income
Revenues	$ 2,074	$ 2,200	$ 1,617