Electric utility segment - Schedule of Regulatory Assets and Liabilities (Details) - Hawaiian Electric Company, Inc. and Subsidiaries - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Regulatory assets
Regulatory assets	$ 308,115	$ 281,319
Regulatory liabilities
Regulatory liabilities	1,444,144	1,244,083
Cost of removal in excess of salvage value
Regulatory liabilities
Regulatory liabilities	611,729	601,741
Retirement benefit plans
Regulatory liabilities
Regulatory liabilities	444,271	279,553
Income taxes
Regulatory liabilities
Regulatory liabilities	281,735	292,036
Solar tax credits
Regulatory liabilities
Regulatory liabilities	43,814	46,661
Decoupling revenue balancing account and RAM
Regulatory liabilities
Regulatory liabilities	29,370	5,498
Enterprise Resource Planning (ERP) Benefits
Regulatory liabilities
Regulatory liabilities	11,635	12,549
Restoration/remediation (to be determined)
Regulatory liabilities
Regulatory liabilities	11,083	0
ECRC and PPAC
Regulatory liabilities
Regulatory liabilities	4,668	4,296
Other
Regulatory liabilities
Regulatory liabilities	$ 5,839	1,749
Minimum | Cost of removal in excess of salvage value
Regulatory liabilities
Authorized amortization or recovery periods (in years)	1 year
Minimum | Income taxes
Regulatory liabilities
Authorized amortization or recovery periods (in years)	8 years
Minimum | Solar tax credits
Regulatory liabilities
Authorized amortization or recovery periods (in years)	1 year
Minimum | Decoupling revenue balancing account and RAM
Regulatory liabilities
Authorized amortization or recovery periods (in years)	1 year
Minimum | Other
Regulatory liabilities
Remaining amortization or recovery periods (in years)	1 year
Maximum | Cost of removal in excess of salvage value
Regulatory liabilities
Authorized amortization or recovery periods (in years)	79 years
Maximum | Income taxes
Regulatory liabilities
Authorized amortization or recovery periods (in years)	34 years
Maximum | Solar tax credits
Regulatory liabilities
Authorized amortization or recovery periods (in years)	16 years
Current assets
Regulatory assets
Regulatory assets	$ 50,039	53,895
Long-term assets
Regulatory assets
Regulatory assets	258,076	227,424
Current liabilities
Regulatory liabilities
Regulatory liabilities	51,997	26,568
Long-term liabilities
Regulatory liabilities
Regulatory liabilities	1,392,147	1,217,515
Income taxes
Regulatory assets
Regulatory assets	$ 80,923	81,102
Income taxes | Minimum
Regulatory assets
Authorized amortization or recovery periods (in years)	8 years
Income taxes | Maximum
Regulatory assets
Authorized amortization or recovery periods (in years)	34 years
Maui windstorm and wildfire related costs (to be determined by the PUC)
Regulatory assets
Regulatory assets	$ 80,478	52,652
Retirement of Generating Units
Regulatory assets
Regulatory assets	$ 36,168	40,953
Authorized amortization or recovery periods (in years)	9 years
Right-Of-Use Assets
Regulatory assets
Regulatory assets	$ 32,586	19,105
Remaining amortization or recovery periods (in years)	25 years
ECRC and PPAC
Regulatory assets
Regulatory assets	$ 20,677	17,418
Authorized amortization or recovery periods (in years)	1 year
Regulatory liabilities
Remaining amortization or recovery periods (in years)	1 year
Vacation earned, but not yet taken
Regulatory assets
Regulatory assets	$ 14,174	13,950
Authorized amortization or recovery periods (in years)	1 year
Wildfire Mitigation Plan (WMP) (to be determined by the PUC)
Regulatory assets
Regulatory assets	$ 9,561	0
Performance Incentive Mechanisms
Regulatory assets
Regulatory assets	$ 8,875	6,783
Authorized amortization or recovery periods (in years)	1 year
COVID-19 related costs (2 years)
Regulatory assets
Regulatory assets	$ 3,597	6,715
Authorized amortization or recovery periods (in years)	2 years
Retirement benefit plans (balance primarily varies with plans’ funded statuses)
Regulatory assets
Regulatory assets	$ 2,355	13,755
Decoupling revenue balancing account and RAM
Regulatory assets
Regulatory assets	$ 0	9,829
Authorized amortization or recovery periods (in years)	1 year
Other
Regulatory assets
Regulatory assets	$ 18,721	$ 19,057
Other | Minimum
Regulatory assets
Remaining amortization or recovery periods (in years)	1 year
Other | Maximum
Regulatory assets
Remaining amortization or recovery periods (in years)	34 years