Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
General payment period	30 days
Revenues from contracts with customers	$ 2,521,425	$ 2,269,451
Revenues from other sources	328,954	310,324
Total revenues	2,850,379	2,579,775	$ 2,873,948
Services/goods transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46,658	38,887
Services/goods transferred over time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,474,767	2,230,564
Electric energy sales - residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	830,653	766,609
Electric energy sales - commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	791,424	703,516
Electric energy sales - large light and power
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	837,834	751,464
Electric energy sales - other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	10,770	8,054
Bank fees
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46,658	38,887
Other sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,086	921
Regulatory revenue
Disaggregation of Revenue [Line Items]
Revenues from other sources	40,069	11,869
Bank interest and dividend income
Disaggregation of Revenue [Line Items]
Revenues from other sources	242,266	244,663
Other bank noninterest income
Disaggregation of Revenue [Line Items]
Revenues from other sources	17,474	29,961
Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	29,145	23,831
Hawaiian Electric Company, Inc. and Subsidiaries
Disaggregation of Revenue [Line Items]
Revenue taxes, other than income tax expense	226,000	202,000	226,000
Revenue taxes accrued	128,000	111,000
Electric utility
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,470,681	2,229,643
Revenues from other sources	68,955	35,677
Total revenues	2,539,636	2,265,320	2,545,942
Electric utility | Services/goods transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric utility | Services/goods transferred over time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,470,681	2,229,643
Electric utility | Electric energy sales - residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	830,653	766,609
Electric utility | Electric energy sales - commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	791,424	703,516
Electric utility | Electric energy sales - large light and power
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	837,834	751,464
Electric utility | Electric energy sales - other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	10,770	8,054
Electric utility | Bank fees
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric utility | Other sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric utility | Regulatory revenue
Disaggregation of Revenue [Line Items]
Revenues from other sources	40,069	11,869
Electric utility | Bank interest and dividend income
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Electric utility | Other bank noninterest income
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Electric utility | Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	28,886	23,808
Bank
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46,658	38,887
Revenues from other sources	259,740	274,624
Total revenues	306,398	313,511	327,917
Bank | Services/goods transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46,658	38,887
Bank | Services/goods transferred over time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Bank | Electric energy sales - residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Bank | Electric energy sales - commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Bank | Electric energy sales - large light and power
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Bank | Electric energy sales - other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Bank | Bank fees
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46,658	38,887
Bank | Other sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Bank | Regulatory revenue
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Bank | Bank interest and dividend income
Disaggregation of Revenue [Line Items]
Revenues from other sources	242,266	244,663
Bank | Other bank noninterest income
Disaggregation of Revenue [Line Items]
Revenues from other sources	17,474	29,961
Bank | Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,086	921
Revenues from other sources	259	23
Total revenues	4,345	944	$ 89
Other | Services/goods transferred at a point in time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other | Services/goods transferred over time
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,086	921
Other | Electric energy sales - residential
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other | Electric energy sales - commercial
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other | Electric energy sales - large light and power
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other | Electric energy sales - other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other | Bank fees
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other | Other sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	4,086	921
Other | Regulatory revenue
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Other | Bank interest and dividend income
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Other | Other bank noninterest income
Disaggregation of Revenue [Line Items]
Revenues from other sources	0	0
Other | Other
Disaggregation of Revenue [Line Items]
Revenues from other sources	$ 259	$ 23