Electric utility segment - Regulatory Proceedings (Details)			3 Months Ended	4 Months Ended	12 Months Ended
	Jan. 31, 2024 USD ($) project	Dec. 23, 2020 USD ($)	Nov. 30, 2021 agreement	Mar. 31, 2023 agreement	Dec. 31, 2023 USD ($) MWh project	Dec. 31, 2020 contract agreement	Jun. 30, 2023 USD ($)	Feb. 28, 2023 USD ($)	Jun. 17, 2022 mechanism	Dec. 31, 2021 USD ($)	Mar. 23, 2021 mechanism	Feb. 16, 2021 contract	Jul. 09, 2020 agreement	Dec. 31, 2019 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					$ 10,000,000
Low-to-moderate income energy efficiency PIM, accrued award							$ 0
Advanced metering infrastructure utilization PIM, annual maximum reward					$ 2,000,000
Advanced metering infrastructure utilization PIM, duration (in years)					3 years
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Number of performance incentive mechanisms | mechanism									2		2
Multi-year rate period (in years)		5 years
Customer dividend, negative adjustment percentage		0.0022%
Savings commitment liability, annual rate		$ 6,600,000
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					$ 33,100,000
EPRM number of projects approved | project					3
EPRM project costs					$ 123,500,000
EPRM number of projects | project					3
EPRM total project costs					$ 215,900,000
2022 deferred cost recovery approved								$ 400,000
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					$ 6,400,000
Service reliability, estimated penalties					$ (3,700,000)
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					$ 1,400,000
Number of contracts which qualified for incentives | contract						7
Public utility, incentives accrued										$ 100,000				$ 1,700,000
Number of grid service purchase agreements | agreement													2
Number of additional power purchase contracts | contract												1
Number of power purchase contracts approved | agreement			2
Number of GSPAs approved | agreement						2
Public utilities, number of power purchase agreements terminated | agreement				2
Interpolated statutory RPS goal rate, years 2021 and 2022 | MWh					20
Interpolated statutory RPS goal rate, year 2023 | 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					$ 400,000
Grid services procurement PIM, maximum reward					1,500,000
Public utilities, grid services procurement performance incentive mechanism, accrued estimated rewards					1,100,000
Interconnection approval PIM, annual maximum reward					3,000,000
Interconnection approval PIM, annual maximum penalty					900,000
Interconnection approval PIM, accrued estimated rewards					3,000,000
Low-to-moderate income energy efficiency PIM, rewards cap					$ 2,000,000
Low-to-moderate income energy efficiency PIM, duration (in years)					3 years
Target performance historical measurement period (in years)					10 years
Maximum penalty, percent of return on equity					0.03%
Pending adjusted amount					$ 1,000,000
Target performance period (in months)					10 months
Target deadband period (in months)					2 months
Accrued estimated rewards, net of penalties					$ 900,000
Hawaiian Electric Company, Inc. and Subsidiaries | Subsequent Event
Regulatory Projects and Legal Obligations [Line Items]
EPRM number of projects approved | project	1
EPRM project costs	$ 95,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | Schofield Generation Station
Regulatory Projects and Legal Obligations [Line Items]
Major project interim recovery requested amount					16,500,000
Hawaiian Electric Company, Inc. and Subsidiaries | West Loch PV Project
Regulatory Projects and Legal Obligations [Line Items]
Major project interim recovery requested amount					3,300,000
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					11,200,000
Hawaiian Electric Company, Inc. and Subsidiaries | Waiawa UFLS Project
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount					100,000
Hawaiian Electric Company, Inc. and Subsidiaries | Waena Switchyard/Synchronous Project
Regulatory Projects and Legal Obligations [Line Items]
EPRM requested amount					2,000,000
Hawaiian Electric
Regulatory Projects and Legal Obligations [Line Items]
Public utility, incentives accrued					$ 100,000
Public utilities retained percentage					20.00%
Accrued estimated rewards, net of penalties					$ 1,200,000
Hawaii Electric Light
Regulatory Projects and Legal Obligations [Line Items]
Accrued estimated rewards, net of penalties					(600,000)
Maui Electric
Regulatory Projects and Legal Obligations [Line Items]
Accrued estimated rewards, net of penalties					$ 300,000