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Electric utility segment - Regulatory Proceedings (Details) $ in Thousands			3 Months Ended
	Dec. 29, 2023 USD ($)	Dec. 23, 2020 USD ($)	Mar. 31, 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			$ 233,050		$ 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			$ 218,500
Number of projects | project			2
Prior year deferred cost recovery approved				$ 2,100
Accrued earned rewards, net of penalties					$ 6,200
Recovery of deferral costs period (in years)	3 years
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			$ 25,900
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			13,900
Hawaiian Electric Company, Inc. and Subsidiaries | Suspension Of Disconnections
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets			3,800
Hawaiian Electric Company, Inc. and Subsidiaries | Natural Disasters and Other Casualty Events
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets			58,300
Hawaiian Electric Company, Inc. and Subsidiaries | COVID-19
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets			5,900
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			$ 12,300
ERP/EAM Implementation Project | Hawaiian Electric, Parent
Regulatory Projects and Legal Obligations [Line Items]
Regulatory liability for O&M expense reductions			800
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

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478742/980-340-50-1

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