Electric utility segment - Most recent rate proceedings (Details) - USD ($) $ in Thousands	1 Months Ended
	Dec. 31, 2021	Mar. 31, 2022
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets	$ 565,543	$ 559,161
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory Projects and Legal Obligations [Line Items]
Regulatory assets		$ 27,800
Hawaiian Electric Company, Inc. and Subsidiaries | COVID-19
Regulatory Projects and Legal Obligations [Line Items]
Customer bill forgiveness	$ 2,000