Regulatory restrictions on net assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Regulatory restrictions on net assets
Common stock equity	$ 1,479,089	$ 2,344,841	$ 2,202,499	$ 2,390,884
Hawaiian Electric Company, Inc. and Subsidiaries
Regulatory restrictions on net assets
Total capitalization, percentage	35.00%
Distribution restrictions, percent of earnings in current year and 5 preceding years if capitalization rate is less than 35%	80.00%
Total capitalization rate of HEI's electric utility subsidiaries	33.00%
Modified capitalization ratio	0.37
Common stock equity	$ 1,156,955	$ 2,409,110	$ 2,344,170	$ 2,261,899