SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - BALANCE SHEETS (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current assets
Restricted cash	$ 492,317	$ 15,028	$ 5,050
Other	380,408	331,617
Noncurrent assets:
Property, plant and equipment, net	6,134,318	5,963,084
Total noncurrent assets	6,797,090	6,471,479
Total assets	8,931,416	17,243,821
Current liabilities:
Accounts payable	203,452	198,885
Current portion of long-term debt, net	109,171	16,496
Other	430,824	403,414
Total liabilities	7,418,034	14,864,687
Noncurrent liabilities:
Long-term debt, net	2,690,387	2,825,933
Other	242,957	247,637
Shareholders’ equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	2,264,544	1,707,471
Retained earnings	(788,916)	926,720
Accumulated other comprehensive income (loss), net of taxes	3,461	(289,350)
Total shareholders’ equity	1,479,089	2,344,841	2,202,499	$ 2,390,884
Total capitalization and liabilities	$ 8,931,416	$ 17,243,821
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)	172,465,608	110,151,798
Common stock, outstanding shares (in shares)	172,465,608	110,151,798
Hawaiian Electric
Current assets
Cash and cash equivalents	$ 564,184	$ 136,510
Restricted cash	6,320	6,216	$ 0
Accounts and intercompany receivables	12,362	9,374
Notes receivable from subsidiaries	684	4,821
Other	8,688	8,432
Total current assets	592,238	165,353
Noncurrent assets:
Property, plant and equipment, net	1,300	1,495
Deferred income tax assets	9,870	9,889
Other assets	7,477	14,510
Investments in subsidiary, at equity - discontinued operations	1,747,992	2,495,235
Total noncurrent assets	1,766,639	2,521,129
Investments in subsidiary, at equity - discontinued operations	0	529,851
Total assets	2,358,877	3,216,333
Current liabilities:
Accounts payable	4,982	8,272
Interest payable	3,262	3,397
Current portion of long-term debt, net	49,962	0
Other	69,295	51,938
Total liabilities	879,788	871,492
Noncurrent liabilities:
Long-term debt, net	730,598	782,005
Retirement benefits liability	19,114	21,876
Other	2,575	4,004
Total noncurrent liabilities	752,287	807,885
Total current liabilities	127,501	63,607
Shareholders’ equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	2,264,544	1,707,471
Retained earnings	(788,916)	926,720
Accumulated other comprehensive income (loss), net of taxes	3,461	(289,350)
Total shareholders’ equity	1,479,089	2,344,841
Total capitalization and liabilities	$ 2,358,877	$ 3,216,333
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)	172,465,608	110,151,798
Common stock, outstanding shares (in shares)	172,465,608	110,151,798