Electric utility segment - Condensed consolidating statement of cash flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Cash flows from operating activities
Net cash provided by operating activities	$ 74,642	$ 117,587
Cash flows from investing activities
Capital expenditures	(147,749)	(148,414)
Other	15,813	7,805
Net cash used in investing activities	(497,031)	(771,432)
Cash flows from financing activities
Common stock dividends	(76,602)	(74,311)
Repayment of short-term debt	0	(65,000)
Proceeds from issuance of long-term debt	67,312	191,487
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	153,305	39,995
Other	(318)	(2,037)
Net cash provided by financing activities	275,985	552,927
Net decrease in cash, cash equivalents and restricted cash	(146,404)	(100,918)
Cash, cash equivalents and restricted cash, beginning of period	311,462	358,979
Cash, cash equivalents and restricted cash, end of period	165,058	258,061
Less: Restricted cash	(5,386)	(10,618)	$ (5,911)
Cash and cash equivalents, end of period	159,672	247,443	305,551
Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	44,150	57,453
Cash flows from investing activities
Capital expenditures	(140,245)	(138,025)
Advances to affiliates	0	0
Other	6,685	4,670
Net cash used in investing activities	(133,560)	(133,355)
Cash flows from financing activities
Common stock dividends	(62,950)	(55,850)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(998)	(998)
Repayment of short-term debt	0	(50,000)
Proceeds from issuance of long-term debt	60,000	115,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	54,987	37,999
Other	(255)	(941)
Net cash provided by financing activities	50,784	45,210
Net decrease in cash, cash equivalents and restricted cash	(38,626)	(30,692)
Cash, cash equivalents and restricted cash, beginning of period	55,258	63,326
Cash, cash equivalents and restricted cash, end of period	16,632	32,634
Less: Restricted cash	(1,129)	(8,968)	(3,089)
Cash and cash equivalents, end of period	15,503	23,666	52,169
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric
Cash flows from operating activities
Net cash provided by operating activities	25,367	43,623
Cash flows from investing activities
Capital expenditures	(87,892)	(92,352)
Advances to affiliates	(2,000)	22,900
Other	4,471	3,087
Net cash used in investing activities	(85,421)	(66,365)
Cash flows from financing activities
Common stock dividends	(62,950)	(55,850)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(540)	(540)
Repayment of short-term debt		(50,000)
Proceeds from issuance of long-term debt	40,000	60,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	64,987	37,999
Other	(169)	(703)
Net cash provided by financing activities	41,328	(9,094)
Net decrease in cash, cash equivalents and restricted cash	(18,726)	(31,836)
Cash, cash equivalents and restricted cash, beginning of period	26,433	58,171
Cash, cash equivalents and restricted cash, end of period	7,707	26,335
Less: Restricted cash	(1,129)	(8,968)	(3,089)
Cash and cash equivalents, end of period	6,578	17,367	23,344
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Cash flows from operating activities
Net cash provided by operating activities	19,742	15,315
Cash flows from investing activities
Capital expenditures	(23,638)	(22,135)
Advances to affiliates	0	0
Other	834	911
Net cash used in investing activities	(22,804)	(21,224)
Cash flows from financing activities
Common stock dividends	(8,200)	(7,300)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(267)	(267)
Repayment of short-term debt		0
Proceeds from issuance of long-term debt	10,000	30,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	2,000	(15,700)
Other	(43)	(116)
Net cash provided by financing activities	3,490	6,617
Net decrease in cash, cash equivalents and restricted cash	428	708
Cash, cash equivalents and restricted cash, beginning of period	5,326	3,046
Cash, cash equivalents and restricted cash, end of period	5,754	3,754
Less: Restricted cash	0	0	0
Cash and cash equivalents, end of period	5,754	3,754	5,326
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Cash flows from operating activities
Net cash provided by operating activities	14,841	13,365
Cash flows from investing activities
Capital expenditures	(28,715)	(23,538)
Advances to affiliates	(10,000)	0
Other	1,380	672
Net cash used in investing activities	(37,335)	(22,866)
Cash flows from financing activities
Common stock dividends	(7,600)	(7,550)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(191)	(191)
Repayment of short-term debt		0
Proceeds from issuance of long-term debt	10,000	25,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	0	(7,200)
Other	(43)	(122)
Net cash provided by financing activities	2,166	9,937
Net decrease in cash, cash equivalents and restricted cash	(20,328)	436
Cash, cash equivalents and restricted cash, beginning of period	23,422	2,032
Cash, cash equivalents and restricted cash, end of period	3,094	2,468
Less: Restricted cash	0	0	0
Cash and cash equivalents, end of period	3,094	2,468	23,422
Hawaiian Electric Consolidated | Reportable Legal Entities | Other subsidiaries
Cash flows from operating activities
Net cash provided by operating activities	0	0
Cash flows from investing activities
Capital expenditures	0	0
Advances to affiliates	0	0
Other	0	0
Net cash used in investing activities	0	0
Cash flows from financing activities
Common stock dividends	0	0
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Repayment of short-term debt		0
Proceeds from issuance of long-term debt	0	0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	0	0
Other	0	0
Net cash provided by financing activities	0	0
Net decrease in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash, beginning of period	77	77
Cash, cash equivalents and restricted cash, end of period	77	77
Less: Restricted cash	0	0	0
Cash and cash equivalents, end of period	77	77	77
Hawaiian Electric Consolidated | Consolidating adjustments
Cash flows from operating activities
Net cash provided by operating activities	(15,800)	(14,850)
Cash flows from investing activities
Capital expenditures	0	0
Advances to affiliates	12,000	(22,900)
Other	0	0
Net cash used in investing activities	12,000	(22,900)
Cash flows from financing activities
Common stock dividends	15,800	14,850
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Repayment of short-term debt		0
Proceeds from issuance of long-term debt	0	0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	(12,000)	22,900
Other	0	0
Net cash provided by financing activities	3,800	37,750
Net decrease in cash, cash equivalents and restricted cash	0	0
Cash, cash equivalents and restricted cash, beginning of period	0	0
Cash, cash equivalents and restricted cash, end of period	0	0
Less: Restricted cash	0	0	0
Cash and cash equivalents, end of period	$ 0	$ 0	$ 0