Electric utility segment - Regulatory Assets and Liability Narrative (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 29, 2023	Dec. 31, 2025	Dec. 31, 2024	Sep. 30, 2024	Dec. 22, 2023	Jun. 10, 2019	Oct. 31, 2018
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		$ 308,115	$ 281,319
Recovery of deferral costs period (in years)	3 years
Regulatory liabilities		1,444,144	1,244,083
Hawaiian Electric Company, Inc. and Subsidiaries | Restoration/remediation
Regulatory Projects and Legal Obligations [Line Items]
Regulatory liabilities		$ 11,083	0
Hawaiian Electric Company, Inc. and Subsidiaries | ERP/EAM Implementation Project
Regulatory Projects and Legal Obligations [Line Items]
ERP/EAM project service period (in years)		12 years
ERP/EAM required pass-through savings							$ 246,000
ERP/EAM implementation project, expected future O&M expense reductions						$ 150,000
ERP/EAM implementation project, future cost avoidance related to capital costs and tax costs						$ 96,000
Regulatory liability, amortization period		5 years
ERP/EAM regulatory liability for operation and maintenance expense reductions		$ 11,600
Hawaiian Electric Company, Inc. and Subsidiaries | Natural Disasters and Other Casualty Events
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		80,500
Hawaiian Electric Company, Inc. and Subsidiaries | COVID-19
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		3,600
Public utilities in regulatory assets	$ 8,700
Hawaiian Electric | ERP/EAM Implementation Project
Regulatory Projects and Legal Obligations [Line Items]
ERP/EAM regulatory liability for operation and maintenance expense reductions		0
Hawaii Electric Light | ERP/EAM Implementation Project
Regulatory Projects and Legal Obligations [Line Items]
ERP/EAM regulatory liability for operation and maintenance expense reductions		4,700
Maui Electric | ERP/EAM Implementation Project
Regulatory Projects and Legal Obligations [Line Items]
ERP/EAM regulatory liability for operation and maintenance expense reductions		6,900
Honolulu Generating Units 8 and 9 | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		23,400
Regulatory asset amortization period					9 years
Waiau Generating Units 3 and 4 | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		12,700
Regulatory asset amortization period				9 years
Suspension Of Disconnections | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		5,400
Wildfire Mitigation Plan (WMP) (to be determined by the PUC) | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		$ 9,561	$ 0