Electric utility segment - Regulatory Proceedings (Details) $ in Thousands				6 Months Ended
	Jul. 28, 2025 USD ($) project	Dec. 29, 2023 USD ($)	Dec. 23, 2020 USD ($)	Jun. 30, 2025 USD ($) project	Mar. 24, 2025 USD ($)	Dec. 31, 2024 USD ($)	Jun. 10, 2019 USD ($)	Oct. 31, 2018 USD ($)
Regulatory Projects and Legal Obligations [Line Items]
PUC proposal period (in days)			45 days
Public utilities, modified pilot process proposal period (in days)				15 days
Propose pilots annual cap				$ 10,000
Regulatory assets				$ 241,960		$ 227,424
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Multi-year rate period (in years)			5 years
Customer dividend, negative adjustment percentage			0.22%
Savings commitment liability, annual rate			$ 6,600
Earnings sharing mechanism, actual return on equity, dead band percentage above or below target				3.00%
Approved return on equity, percentage				9.50%
Percentage sharing between customers and utilities				0.50
Earnings sharing mechanism, actual earning, above or below dead band				1.50%
Percentage sharing for any further difference				0.90
MPIR and EPRM requested amount				$ 35,700
EPRM approved projects | project				4
EPRM approved projects, capital costs				$ 215,200
Number of projects | project				3
Prior year deferred cost recovery approved					$ 2,100
Accrued earned rewards, net of penalties				$ 300		$ 6,200
Recovery of deferral costs period (in years)		3 years
Hawaiian Electric Company, Inc. and Subsidiaries | Subsequent Event
Regulatory Projects and Legal Obligations [Line Items]
EPRM approved projects | project	1
EPRM approved projects, granting additional recoveries	$ 12,300
Hawaiian Electric Company, Inc. and Subsidiaries | Honolulu Generating Units 8 and 9
Regulatory Projects and Legal Obligations [Line Items]
Regulatory asset amortization period				9 years
Regulatory assets				$ 25,100
Hawaiian Electric Company, Inc. and Subsidiaries | Waiau Generating Units 3 and 4
Regulatory Projects and Legal Obligations [Line Items]
Regulatory asset amortization period						9 years
Regulatory assets				13,500
Hawaiian Electric Company, Inc. and Subsidiaries | Suspension Of Disconnections
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets				4,300
Hawaiian Electric Company, Inc. and Subsidiaries | Natural Disasters and Other Casualty Events
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets				68,200
Hawaiian Electric Company, Inc. and Subsidiaries | COVID-19
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets				5,200
Public utilities in regulatory assets		$ 8,700
Hawaiian Electric, Parent
Regulatory Projects and Legal Obligations [Line Items]
Accrued earned rewards, net of penalties						$ 2,500
Hawaii Electric Light Company, Inc
Regulatory Projects and Legal Obligations [Line Items]
Accrued earned rewards, net of penalties						3,400
Maui Electric
Regulatory Projects and Legal Obligations [Line Items]
Accrued earned rewards, net of penalties						$ 300
Schofield Generation Station | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
MPIR requested amount				15,600
West Loch PV Project | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
MPIR requested amount				3,100
Grid Modernization Strategy Phase 1 Project | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
MPIR requested amount				14,100
Waiawa UFLS Project | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount				100
Waena Switchyard/Synchronous Project | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount				2,500
Resilience Project | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount				$ 300
ERP/EAM Implementation Project | Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
ERP/EAM project service period (in years)				12 years
ERP/EAM project service, savings over 12 years								$ 246,000
Future O&M expense reductions							$ 150,000
Future cost avoidance related to capital cost and tax costs							$ 96,000
Regulatory liability, amortization period (in years)				5 years
Regulatory liability for O&M expense reductions				$ 12,000
ERP/EAM Implementation Project | Hawaiian Electric, Parent
Regulatory Projects and Legal Obligations [Line Items]
Regulatory liability for O&M expense reductions				500
ERP/EAM Implementation Project | Hawaii Electric Light Company, Inc
Regulatory Projects and Legal Obligations [Line Items]
Regulatory liability for O&M expense reductions				4,600
ERP/EAM Implementation Project | Maui Electric
Regulatory Projects and Legal Obligations [Line Items]
Regulatory liability for O&M expense reductions				$ 6,900