SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF INCOME (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Revenues	$ 2,521,425	$ 2,269,451
Expenses:
Depreciation of property, plant and equipment	246,158	238,114	$ 229,858
Total expenses	2,464,313	2,268,282	2,525,927
Less: Retirement defined benefits expense (credit)—other than service costs	(5,848)	3,210	2,806
Interest expense	99,403	99,808	109,339
Income before income taxes	310,863	240,624	271,409
Income tax benefits	(62,807)	(40,910)	(51,637)
Net income (loss)	248,056	199,714	219,772
Hawaiian Electric (parent only)
Revenues
Revenues	105	208	777
Equity in net income of subsidiaries	278,743	227,098	246,005
Expenses:
Operating, administrative and general	24,006	20,731	19,195
Depreciation of property, plant and equipment	414	485	570
Taxes, other than income taxes	514	654	570
Total expenses	24,934	21,870	20,335
Income before interest expense and income tax benefits	253,914	205,436	226,447
Less: Retirement defined benefits expense (credit)—other than service costs	(114)	634	442
Interest expense	18,444	18,237	17,930
Income before income taxes	235,584	186,565	208,075
Income tax benefits	10,582	11,259	9,807
Net income (loss)	$ 246,166	$ 197,824	$ 217,882