SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - BALANCE SHEETS (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 305,551	$ 341,421
Accounts receivable	344,213	281,216
Property, plant and equipment, net	5,392,068	5,265,735
Other assets and intercompany receivables	747,469	629,149
Total assets	15,822,637	15,004,007	$ 13,745,251
Liabilities
Accounts payable	205,544	182,347
Long-term debt, net	2,321,937	2,119,129
Other	669,215	618,438
Total liabilities	13,397,460	12,632,212
Shareholders’ equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	1,685,496	1,678,368
Retained earnings	757,921	660,398
Accumulated other comprehensive loss, net of tax benefits	(52,533)	(1,264)
Total shareholders’ equity	2,390,884	2,337,502	$ 2,280,260	$ 2,162,280
Total capitalization and liabilities	$ 15,822,637	$ 15,004,007
Preferred stock, authorized shares (in shares)	10,000,000	10,000,000
Common stock, authorized shares (in shares)	200,000,000	200,000,000
Common stock, issued shares (in shares)	109,311,785	109,181,124
Common stock, outstanding shares (in shares)	109,311,785	109,181,124
Hawaiian Electric (parent only)
Assets
Cash and cash equivalents	$ 479	$ 299
Accounts receivable	873	738
Property, plant and equipment, net	2,052	2,456
Deferred income tax assets	17,000	14,236
Other assets and intercompany receivables	15,940	18,726
Investments in subsidiaries, at equity	3,025,729	2,893,781
Total assets	3,062,073	2,930,236
Liabilities
Accounts payable	914	673
Interest payable	2,238	2,918
Commercial paper	53,998	64,491
Short-term borrowings from non-affiliate	0	14,909
Long-term debt, net	548,480	449,145
Retirement benefits liability	26,340	31,688
Other	39,219	28,910
Total liabilities	671,189	592,734
Shareholders’ equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	1,685,496	1,678,368
Retained earnings	757,921	660,398
Accumulated other comprehensive loss, net of tax benefits	(52,533)	(1,264)
Total shareholders’ equity	2,390,884	2,337,502
Total capitalization and liabilities	$ 3,062,073	$ 2,930,236
Preferred stock, authorized shares (in shares)	10,000,000	10,000,000
Preferred stock, issued shares (in shares)	0	0
Common stock, authorized shares (in shares)	200,000,000	200,000,000
Common stock, issued shares (in shares)	109,311,785	109,181,124
Common stock, outstanding shares (in shares)	109,311,785	109,181,124