SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net cash provided by operating activities	$ 375,673	$ 429,407	$ 512,470
Cash flows from investing activities
Capital expenditures	(314,524)	(383,895)	(457,520)
Other, net	27	3,412	13,291
Net cash used in investing activities	(1,179,592)	(1,413,648)	(541,709)
Cash flows from financing activities
Net increase (decrease) in short-term borrowings with original maturities of three months or less	(10,493)	(71,219)	86,718
Proceeds from issuance of short-term debt	0	165,000	75,000
Repayment of short-term debt	(65,000)	(150,000)	(50,000)
Proceeds from issuance of long-term debt	285,886	415,997	289,349
Repayment of long-term debt	(82,262)	(178,969)	(287,285)
Common stock dividends	(148,643)	(144,096)	(139,463)
Other	(3,080)	(3,203)	(1,836)
Net cash used in financing activities	756,402	1,115,535	87,716
Net increase (decrease) in cash and equivalents	(47,517)	131,294	58,477
Cash, cash equivalents and restricted cash, January 1	358,979	227,685	169,208
Cash, cash equivalents and restricted cash, December 31	311,462	358,979	227,685
Hawaiian Electric (parent only)
Cash flows from operating activities
Net cash provided by operating activities	154,151	134,363	131,120
Cash flows from investing activities
Increase in note receivable from subsidiary	0	0	(1,187)
Decrease in note receivable from subsidiary	0	22,719	0
Capital expenditures	(10)	(20)	(47)
Investments in subsidiaries	(76,232)	(42,664)	(38,935)
Other, net	180	2,435	(1,001)
Net cash used in investing activities	(76,062)	(17,530)	(41,170)
Cash flows from financing activities
Net increase (decrease) in short-term borrowings with original maturities of three months or less	(10,493)	(32,232)	47,731
Proceeds from issuance of short-term debt	0	65,000	0
Repayment of short-term debt	(15,000)	(50,000)	0
Proceeds from issuance of long-term debt	150,000	50,000	0
Repayment of long-term debt	(50,000)	0	0
Proceeds from issuance of syndicated credit facility	0	66,300	0
Repayment of syndicated credit facility	0	(66,300)	0
Withheld shares for employee taxes on vested share-based compensation	(2,006)	(5,700)	(997)
Common stock dividends	(148,643)	(144,096)	(139,463)
Other	(1,767)	(459)	(10)
Net cash used in financing activities	(77,909)	(117,487)	(92,739)
Net increase (decrease) in cash and equivalents	180	(654)	(2,789)
Cash, cash equivalents and restricted cash, January 1	299	953	3,742
Cash, cash equivalents and restricted cash, December 31	$ 479	$ 299	$ 953