Electric utility segment - Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Regulatory assets
Regulatory assets	$ 294,804	$ 242,513
Regulatory liabilities
Regulatory liabilities	1,150,690	1,055,650
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	294,804	242,513
Regulatory liabilities
Regulatory liabilities	1,150,690	1,055,650
Hawaiian Electric Company, Inc. and Subsidiaries | Cost of removal in excess of salvage value
Regulatory liabilities
Regulatory liabilities	591,298	577,985
Hawaiian Electric Company, Inc. and Subsidiaries | Income taxes
Regulatory liabilities
Regulatory liabilities	303,225	316,947
Hawaiian Electric Company, Inc. and Subsidiaries | Decoupling revenue balancing account and RAM
Regulatory liabilities
Regulatory liabilities	5,995	10,426
Hawaiian Electric Company, Inc. and Subsidiaries | Retirement benefit plans
Regulatory liabilities
Regulatory liabilities	171,421	81,950
Hawaiian Electric Company, Inc. and Subsidiaries | Solar tax credits
Regulatory liabilities
Regulatory liabilities	49,507	50,240
Hawaiian Electric Company, Inc. and Subsidiaries | ECRC and PPAC
Regulatory liabilities
Regulatory liabilities	15,169	4,034
Hawaiian Electric Company, Inc. and Subsidiaries | Enterprise Resource Planning (ERP) Benefits
Regulatory liabilities
Regulatory liabilities	$ 12,409	10,491
Remaining amortization or recovery periods (in years)	2 years
Hawaiian Electric Company, Inc. and Subsidiaries | Other
Regulatory liabilities
Regulatory liabilities	$ 1,666	3,577
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Cost of removal in excess of salvage value
Regulatory liabilities
Authorized amortization or recovery periods (in years)	1 year
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Income taxes
Regulatory liabilities
Authorized amortization or recovery periods (in years)	2 years
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Decoupling revenue balancing account and RAM
Regulatory liabilities
Authorized amortization or recovery periods (in years)	1 year
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Solar tax credits
Regulatory liabilities
Authorized amortization or recovery periods (in years)	1 year
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Other
Regulatory liabilities
Remaining amortization or recovery periods (in years)	1 year
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum | Cost of removal in excess of salvage value
Regulatory liabilities
Authorized amortization or recovery periods (in years)	79 years
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum | Income taxes
Regulatory liabilities
Authorized amortization or recovery periods (in years)	36 years
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum | Decoupling revenue balancing account and RAM
Regulatory liabilities
Authorized amortization or recovery periods (in years)	2 years
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum | Solar tax credits
Regulatory liabilities
Authorized amortization or recovery periods (in years)	18 years
Hawaiian Electric Company, Inc. and Subsidiaries | Current assets
Regulatory assets
Regulatory assets	$ 68,453	52,273
Hawaiian Electric Company, Inc. and Subsidiaries | Long-term assets
Regulatory assets
Regulatory assets	226,351	190,240
Hawaiian Electric Company, Inc. and Subsidiaries | Current liabilities
Regulatory liabilities
Regulatory liabilities	36,559	31,475
Hawaiian Electric Company, Inc. and Subsidiaries | Long-term liabilities
Regulatory liabilities
Regulatory liabilities	1,114,131	1,024,175
Retirement benefit plans (balance primarily varies with plans’ funded statuses) | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	70,616	69,919
Income taxes | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 81,620	82,583
Income taxes | Hawaiian Electric Company, Inc. and Subsidiaries | Minimum
Regulatory assets
Authorized amortization or recovery periods (in years)	2 years
Income taxes | Hawaiian Electric Company, Inc. and Subsidiaries | Maximum
Regulatory assets
Authorized amortization or recovery periods (in years)	36 years
Decoupling revenue balancing account and RAM | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 19,002	14,290
Decoupling revenue balancing account and RAM | Hawaiian Electric Company, Inc. and Subsidiaries | Minimum
Regulatory assets
Authorized amortization or recovery periods (in years)	1 year
Decoupling revenue balancing account and RAM | Hawaiian Electric Company, Inc. and Subsidiaries | Maximum
Regulatory assets
Authorized amortization or recovery periods (in years)	2 years
Right-Of-Use Assets | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 9,067	7,711
Remaining amortization or recovery periods (in years)	21 years
Vacation earned, but not yet taken | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 14,585	14,109
Authorized amortization or recovery periods (in years)	1 year
COVID-19 related costs (to be determined by PUC) | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 8,715	11,403
ECRC and PPAC | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 24,691	20,369
Authorized amortization or recovery periods (in years)	1 year
Maui windstorm and wildfire related costs (to be determined by PUC) | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 14,692	0
Retirement of Generating Units | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 29,930	0
Authorized amortization or recovery periods (in years)	10 years
Other | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory assets
Regulatory assets	$ 21,886	$ 22,129
Other | Hawaiian Electric Company, Inc. and Subsidiaries | Minimum
Regulatory assets
Remaining amortization or recovery periods (in years)	1 year
Other | Hawaiian Electric Company, Inc. and Subsidiaries | Maximum
Regulatory assets
Remaining amortization or recovery periods (in years)	36 years