Electric utility segment - Condensed consolidating statement of cash flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Cash flows from operating activities
Net cash provided by operating activities	$ 92,585	$ 41,730
Cash flows from investing activities
Capital expenditures	(79,163)	(74,079)
Other	5,340	4,622
Net cash used in investing activities	(227,714)	(518,020)
Cash flows from financing activities
Common stock dividends	(38,301)	(37,156)
Repayment of short-term debt	0	(65,000)
Proceeds from issuance of long-term debt	7,312	161,800
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	49,080	13,015
Other	(4,377)	(4,621)
Net cash provided by financing activities	131,283	408,957
Net decrease in cash, cash equivalents and restricted cash	(3,846)	(67,333)
Cash, cash equivalents and restricted cash, beginning of period	311,462	358,979
Cash, cash equivalents and restricted cash, end of period	307,616	291,646
Less: Restricted cash	(5,912)	(14,067)	$ (5,911)
Cash and cash equivalents, end of period	301,704	277,579	305,551
Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	76,775	31,961
Cash flows from investing activities
Capital expenditures	(76,358)	(70,361)
Advances to affiliates	0	0
Other	1,494	1,863
Net cash used in investing activities	(74,864)	(68,498)
Cash flows from financing activities
Common stock dividends	(31,475)	(27,925)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(499)	(499)
Repayment of short-term debt	0	(50,000)
Proceeds from issuance of long-term debt	0	115,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	6,000	0
Other	0	(116)
Net cash provided by financing activities	(25,974)	36,460
Net decrease in cash, cash equivalents and restricted cash	(24,063)	(77)
Cash, cash equivalents and restricted cash, beginning of period	55,258	63,326
Cash, cash equivalents and restricted cash, end of period	31,195	63,249
Less: Restricted cash	(2,140)	(11,506)	(3,089)
Cash and cash equivalents, end of period	29,055	51,743	52,169
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric Industries, Inc.
Cash flows from operating activities
Net cash provided by operating activities	55,669	18,764
Cash flows from investing activities
Capital expenditures	(44,084)	(45,293)
Advances to affiliates	(4,000)	26,700
Other	961	1,182
Net cash used in investing activities	(47,123)	(17,411)
Cash flows from financing activities
Common stock dividends	(31,475)	(27,925)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(270)	(270)
Repayment of short-term debt		(50,000)
Proceeds from issuance of long-term debt		60,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	18,800	0
Other		(96)
Net cash provided by financing activities	(12,945)	(18,291)
Net decrease in cash, cash equivalents and restricted cash	(4,399)	(16,938)
Cash, cash equivalents and restricted cash, beginning of period	26,433	58,171
Cash, cash equivalents and restricted cash, end of period	22,034	41,233
Less: Restricted cash	(2,140)	(11,506)	(3,089)
Cash and cash equivalents, end of period	19,894	29,727	23,344
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Cash flows from operating activities
Net cash provided by operating activities	15,778	9,635
Cash flows from investing activities
Capital expenditures	(15,133)	(12,728)
Advances to affiliates	0	0
Other	280	372
Net cash used in investing activities	(14,853)	(12,356)
Cash flows from financing activities
Common stock dividends	(4,100)	(3,650)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(134)	(134)
Repayment of short-term debt		0
Proceeds from issuance of long-term debt		30,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	4,000	(18,800)
Other		(11)
Net cash provided by financing activities	(234)	7,405
Net decrease in cash, cash equivalents and restricted cash	691	4,684
Cash, cash equivalents and restricted cash, beginning of period	5,326	3,046
Cash, cash equivalents and restricted cash, end of period	6,017	7,730
Less: Restricted cash	0	0	0
Cash and cash equivalents, end of period	6,017	7,730	5,326
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Cash flows from operating activities
Net cash provided by operating activities	13,228	10,988
Cash flows from investing activities
Capital expenditures	(17,141)	(12,340)
Advances to affiliates	(12,800)	0
Other	253	309
Net cash used in investing activities	(29,688)	(12,031)
Cash flows from financing activities
Common stock dividends	(3,800)	(3,776)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(95)	(95)
Repayment of short-term debt		0
Proceeds from issuance of long-term debt		25,000
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	0	(7,900)
Other		(9)
Net cash provided by financing activities	(3,895)	13,220
Net decrease in cash, cash equivalents and restricted cash	(20,355)	12,177
Cash, cash equivalents and restricted cash, beginning of period	23,422	2,032
Cash, cash equivalents and restricted cash, end of period	3,067	14,209
Less: Restricted cash	0	0	0
Cash and cash equivalents, end of period	3,067	14,209	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
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	0	0
Other		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	(7,900)	(7,426)
Cash flows from investing activities
Capital expenditures	0	0
Advances to affiliates	16,800	(26,700)
Other	0	0
Net cash used in investing activities	16,800	(26,700)
Cash flows from financing activities
Common stock dividends	7,900	7,426
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Repayment of short-term debt		0
Proceeds from issuance of long-term debt		0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	(16,800)	26,700
Other		0
Net cash provided by financing activities	(8,900)	34,126
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