Income taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets
Wildfire tort-related claims	$ 483,749	$ 0
Regulatory liabilities, excluding amounts attributable to property, plant and equipment	76,765	78,884
Lease liabilities	130,556	109,480
Retirement benefits	45,879	28,623
Revenue taxes	48,379	49,522
Capital loss carryforward	66,430	0
Other	35,827	27,003
Total deferred income tax assets	887,585	293,512
Valuation allowances	(73,459)	0
Total deferred income tax assets, net	814,126	293,512
Deferred tax liabilities
Property, plant and equipment related	542,109	527,323
Lease right-of-use assets	130,483	109,420
Regulatory assets, excluding amounts attributable to property, plant and equipment	21,678	21,872
Other	47,148	37,103
Total deferred income tax liabilities	741,418	695,718
Net deferred income tax asset (liability)	72,708
Net deferred income tax asset (liability)		(402,206)
Deferred tax assets, tax credit carryforwards	3,800
Hawaiian Electric Company, Inc. and Subsidiaries
Deferred tax assets
Wildfire tort-related claims	483,749	0
Regulatory liabilities, excluding amounts attributable to property, plant and equipment	76,765	78,884
Lease liabilities	128,610	107,409
Retirement benefits	40,568	23,247
Revenue taxes	48,379	49,522
Capital loss carryforward	0	0
Other	22,387	20,817
Total deferred income tax assets	800,458	279,879
Valuation allowances	0	0
Total deferred income tax assets, net	800,458	279,879
Deferred tax liabilities
Property, plant and equipment related	532,257	513,064
Lease right-of-use assets	128,610	107,409
Regulatory assets, excluding amounts attributable to property, plant and equipment	21,678	21,872
Other	46,330	36,535
Total deferred income tax liabilities	728,875	678,880
Net deferred income tax asset (liability)	71,583
Net deferred income tax asset (liability)		$ (399,001)
State and Local Jurisdiction
Deferred tax liabilities
Tax credit carryforward	$ 5,200