Electric utility segment - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Cash flows from operating activities
Net cash provided by operating activities	$ 193,447	$ 371,617
Cash flows from investing activities
Capital expenditures	(179,865)	(235,875)
Other	(4,237)	8,160
Net cash provided by (used in) investing activities	33,523	(282,854)
Cash flows from financing activities
Common stock dividends	0	(78,893)
Proceeds from issuance of long-term debt	4,673	250,000
Net decrease in short-term borrowings with original maturities of three months or less	0	(91,438)
Other	(8,174)	(1,662)
Net cash used in financing activities	(354,714)	25,698
Net increase (decrease) in cash, cash equivalents and restricted cash	(127,744)	114,461
Cash, cash equivalents and restricted cash, beginning of period	694,574	204,927
Cash, cash equivalents and restricted cash, end of period	566,830	319,388
Less: Restricted cash	(16,422)	(5,104)	$ (15,028)
Cash and cash equivalents	550,408	314,284	679,546
Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	185,473	336,145
Cash flows from investing activities
Capital expenditures	(168,200)	(230,149)
Advanced (to) from affiliates	0	0
Other	1,543	4,056
Net cash provided by (used in) investing activities	(166,657)	(226,093)
Cash flows from financing activities
Common stock dividends	(26,000)	(64,500)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(998)	(998)
Proceeds from issuance of long-term debt	0	150,000
Net decrease in short-term borrowings with original maturities of three months or less	0	(87,967)
Payments of obligations under finance leases	(3,737)	(1,339)
Other	(5,538)	(843)
Net cash used in financing activities	(36,273)	(5,647)
Net increase (decrease) in cash, cash equivalents and restricted cash	(17,457)	104,405
Cash, cash equivalents and restricted cash, beginning of period	108,077	39,242
Cash, cash equivalents and restricted cash, end of period	90,620	143,647
Less: Restricted cash	(2,000)	0	(2,000)
Cash and cash equivalents	88,620	143,647	106,077
Consolidating adjustments | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	(1,850)	(16,300)
Cash flows from investing activities
Capital expenditures	0	0
Advanced (to) from affiliates	39,500	(26,200)
Other	1,850	0
Net cash provided by (used in) investing activities	41,350	(26,200)
Cash flows from financing activities
Common stock dividends	0	16,300
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Proceeds from issuance of long-term debt		0
Net decrease in short-term borrowings with original maturities of three months or less	(39,500)	26,200
Payments of obligations under finance leases		0
Other	0	0
Net cash used in financing activities	(39,500)	42,500
Net increase (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
Less: Restricted cash	0		0
Cash and cash equivalents	0	0	0
Hawaiian Electric
Cash flows from financing activities
Cash and cash equivalents	124,400
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	137,811	274,412
Cash flows from investing activities
Capital expenditures	(95,431)	(152,823)
Advanced (to) from affiliates	(39,500)	0
Other	535	2,086
Net cash provided by (used in) investing activities	(134,396)	(150,737)
Cash flows from financing activities
Common stock dividends	(26,000)	(64,500)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(998)	(540)
Proceeds from issuance of long-term debt		100,000
Net decrease in short-term borrowings with original maturities of three months or less	0	(114,167)
Payments of obligations under finance leases	(3,382)	(1,241)
Other	(3,971)	(571)
Net cash used in financing activities	(34,351)	(81,019)
Net increase (decrease) in cash, cash equivalents and restricted cash	(30,936)	42,656
Cash, cash equivalents and restricted cash, beginning of period	91,755	27,579
Cash, cash equivalents and restricted cash, end of period	60,819
Less: Restricted cash	(2,000)		(2,000)
Cash and cash equivalents	58,819	70,235	89,755
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	36,712	43,352
Cash flows from investing activities
Capital expenditures	(27,981)	(33,512)
Advanced (to) from affiliates	0	4,500
Other	245	912
Net cash provided by (used in) investing activities	(27,736)	(28,100)
Cash flows from financing activities
Common stock dividends	0	(8,950)
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	(267)
Proceeds from issuance of long-term debt		25,000
Net decrease in short-term borrowings with original maturities of three months or less	0	0
Payments of obligations under finance leases	(311)	(98)
Other	(459)	(135)
Net cash used in financing activities	(770)	15,550
Net increase (decrease) in cash, cash equivalents and restricted cash	8,206	30,802
Cash, cash equivalents and restricted cash, beginning of period	10,658	5,092
Cash, cash equivalents and restricted cash, end of period	18,864
Less: Restricted cash	0		0
Cash and cash equivalents	18,864	35,894	10,658
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	12,800	34,681
Cash flows from investing activities
Capital expenditures	(44,788)	(43,814)
Advanced (to) from affiliates	0	21,700
Other	(1,087)	1,058
Net cash provided by (used in) investing activities	(45,875)	(21,056)
Cash flows from financing activities
Common stock dividends	0	(7,350)
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	(191)
Proceeds from issuance of long-term debt		25,000
Net decrease in short-term borrowings with original maturities of three months or less	39,500	0
Payments of obligations under finance leases	(44)	0
Other	(1,108)	(137)
Net cash used in financing activities	38,348	17,322
Net increase (decrease) in cash, cash equivalents and restricted cash	5,273	30,947
Cash, cash equivalents and restricted cash, beginning of period	5,587	6,494
Cash, cash equivalents and restricted cash, end of period	10,860
Less: Restricted cash	0		0
Cash and cash equivalents	10,860	37,441	5,587
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	0	0
Cash flows from investing activities
Capital expenditures	0	0
Advanced (to) from affiliates	0	0
Other	0	0
Net cash provided by (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
Proceeds from issuance of long-term debt		0
Net decrease in short-term borrowings with original maturities of three months or less	0	0
Payments of obligations under finance leases		0
Other	0	0
Net cash used in financing activities	0	0
Net increase (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
Less: Restricted cash	0		0
Cash and cash equivalents	$ 77	$ 77	$ 77