Electric utility segment - Regulatory Proceedings (Details) $ in Thousands			12 Months Ended
	Dec. 04, 2024	Dec. 23, 2020 USD ($)	Dec. 31, 2024 USD ($) MWh project	Dec. 31, 2021 contract	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($) agreement	Mar. 11, 2024 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Jun. 17, 2022 mechanism	Dec. 31, 2020 USD ($)
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
Pilot process annual cap			$ 10,000
Pilot processes, deferred and recovered annual expenditures, period			12 months
Low-to-moderate income energy efficiency PIM, accrued award									$ 10
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Number of performance incentive mechanisms | mechanism										2
Multi-year rate period (in years)		5 years
Customer dividend, negative adjustment percentage		0.22%
Savings commitment liability, annual rate		$ 6,600
Actual return on equity, dead band percentage, above or below target			3.00%
Authorized ROE			9.50%
Percentage sharing between customers and utilities			0.50
Actual earnings, above or below dead band			1.50%
Percentage sharing for any further difference			0.90
MPIR and EPRM requested amount			$ 38,000
EPRM number of projects approved | project			4
EPRM project costs			$ 218,500
EPRM number of projects | project			2
EPRM total project costs			$ 294,200
Deferred cost recovery approved							$ 3,000
Request period	12 months
Target performance historical measurement period (in years)			10 years
Service reliability, maximum penalty, percent of return on equity			20.00%
Maximum penalty, pending adjusted amount			$ 3,600
Service reliability, estimated penalties			$ 1,000
Dead band percentage above or below target			3.00%
Call center performance, maximum penalty, percent			8.00%
Call center performance, maximum penalty, pending adjusted amount			$ 1,400
Number of contracts which qualified for incentives | contract				7
Public utility, incentives accrued											$ 1,700
Number of incentive earned power purchase agreements | agreement						2
Interpolated statutory RPS goal rate | MWh			20
Interpolated statutory RPS goal rate, year three | MWh			15
Interpolated statutory RPS goal rate, remainder of MRP | MWh			10
Penalty rate for failure to meet RPS targets | MWh			20
Public utilities, renewable portfolio standard performance incentive mechanism, accrued estimated rewards			$ 1,900
Interconnection approval PIM, annual maximum reward			3,000
Interconnection approval PIM, annual maximum penalty			900
Interconnection approval PIM, accrued estimated rewards			2,400
Low-to-moderate income energy efficiency PIM, rewards cap			$ 2,000
Target performance historical measurement period (in years)			10 years
Maximum penalty, percent of return on equity			0.03%
Pending adjusted amount			$ 1,000
Target performance period (in months)			10 months
Target deadband period (in months)			2 months
Accrued estimated rewards, net of penalties			$ 6,200
Hawaiian Electric Company, Inc. and Subsidiaries | Schofield Generation Station
Regulatory Projects and Legal Obligations [Line Items]
Major project interim recovery requested amount			16,100
Hawaiian Electric Company, Inc. and Subsidiaries | West Loch PV Project
Regulatory Projects and Legal Obligations [Line Items]
Major project interim recovery requested amount			3,200
Hawaiian Electric Company, Inc. and Subsidiaries | Grid Modernization Strategy Phase 1 Project
Regulatory Projects and Legal Obligations [Line Items]
Major project interim recovery requested amount			16,100
Hawaiian Electric Company, Inc. and Subsidiaries | Waiawa UFLS Project
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount			100
Hawaiian Electric Company, Inc. and Subsidiaries | Waena Switchyard/Synchronous Project
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount			$ 2,500
Hawaiian Electric
Regulatory Projects and Legal Obligations [Line Items]
Public utility, incentives accrued						$ 100		$ 100
Public utilities retained percentage			20.00%
Accrued estimated rewards, net of penalties			$ 2,500
Hawaii Electric Light
Regulatory Projects and Legal Obligations [Line Items]
Public utility, incentives accrued					$ 100
Interconnection approval PIM, accrued estimated rewards			2,800
Accrued penalties			100
Accrued estimated rewards, net of penalties			3,400
Maui Electric
Regulatory Projects and Legal Obligations [Line Items]
Accrued estimated rewards, net of penalties			$ 300