Electric utility segment - Condensed Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Cash flows from operating activities
Net cash provided by operating activities	$ 184,416	$ 193,447
Cash flows from investing activities
Capital expenditures	(161,493)	(178,926)
Other	3,222	500
Net cash provided by (used in) investing activities	(152,490)	33,523
Cash flows from financing activities
Repayment of long-term debt	(630,808)	(9,888)
Other	(5,958)	(9,544)
Net cash used in financing activities	(637,890)	(354,714)
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	(605,964)	(127,744)
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	1,242,852	694,574
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period	636,888	566,830
Less: Restricted cash	(482,603)	(16,422)
Cash and cash equivalents	154,285	215,573	$ 750,535
Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	216,246	185,473
Cash flows from investing activities
Capital expenditures	(159,950)	(168,200)
Advanced (to) from affiliates	0	0
Other	5,151	1,543
Net cash provided by (used in) investing activities	(154,799)	(166,657)
Cash flows from financing activities
Common stock dividends	(10,000)	(26,000)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(998)	(998)
Proceeds from capital contribution from parent	540	0
Net decrease in short-term borrowings with original maturities of three months or less	0	0
Repayment of long-term debt	(123,000)	0
Payments of obligations under finance leases	(4,659)	(3,737)
Other	(1,049)	(5,538)
Net cash used in financing activities	(139,166)	(36,273)
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	(77,719)	(17,457)
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	184,148	108,077
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period	106,429	90,620
Less: Restricted cash	0	(2,000)
Cash and cash equivalents	106,429	88,620	184,148
Consolidating adjustments | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	(971)	(1,850)
Cash flows from investing activities
Capital expenditures	0	0
Advanced (to) from affiliates	7,000	39,500
Other	971	1,850
Net cash provided by (used in) investing activities	7,971	41,350
Cash flows from financing activities
Common stock dividends	0	0
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Proceeds from capital contribution from parent	0
Net decrease in short-term borrowings with original maturities of three months or less	(7,000)	(39,500)
Repayment of long-term debt	0
Payments of obligations under finance leases	0
Other	0	0
Net cash used in financing activities	(7,000)	(39,500)
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	0	0
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	0	0
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period		0
Less: Restricted cash		0
Cash and cash equivalents	0	0	0
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	147,248	137,811
Cash flows from investing activities
Capital expenditures	(86,012)	(95,431)
Advanced (to) from affiliates	(7,000)	(39,500)
Other	3,164	535
Net cash provided by (used in) investing activities	(89,848)	(134,396)
Cash flows from financing activities
Common stock dividends	(10,000)	(26,000)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(998)	(998)
Proceeds from capital contribution from parent	540
Net decrease in short-term borrowings with original maturities of three months or less	0	0
Repayment of long-term debt	(123,000)
Payments of obligations under finance leases	(3,982)	(3,382)
Other	(752)	(3,971)
Net cash used in financing activities	(138,192)	(34,351)
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	(80,792)	(30,936)
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	118,367	91,755
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period		60,819
Less: Restricted cash		(2,000)
Cash and cash equivalents	37,575	58,819	118,367
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	37,461	36,712
Cash flows from investing activities
Capital expenditures	(29,553)	(27,981)
Advanced (to) from affiliates	0	0
Other	343	245
Net cash provided by (used in) investing activities	(29,210)	(27,736)
Cash flows from financing activities
Common stock dividends	0	0
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Proceeds from capital contribution from parent	0
Net decrease in short-term borrowings with original maturities of three months or less	0	0
Repayment of long-term debt	0
Payments of obligations under finance leases	(364)	(311)
Other	(87)	(459)
Net cash used in financing activities	(451)	(770)
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	7,800	8,206
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	31,534	10,658
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period		18,864
Less: Restricted cash		0
Cash and cash equivalents	39,334	18,864	31,534
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	28,864	12,800
Cash flows from investing activities
Capital expenditures	(44,385)	(44,788)
Advanced (to) from affiliates	0	0
Other	673	(1,087)
Net cash provided by (used in) investing activities	(43,712)	(45,875)
Cash flows from financing activities
Common stock dividends	0	0
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0
Proceeds from capital contribution from parent	0
Net decrease in short-term borrowings with original maturities of three months or less	7,000	39,500
Repayment of long-term debt	0
Payments of obligations under finance leases	(313)	(44)
Other	(210)	(1,108)
Net cash used in financing activities	6,477	38,348
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	(8,371)	5,273
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	16,456	5,587
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period		10,860
Less: Restricted cash		0
Cash and cash equivalents	8,085	10,860	16,456
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Cash flows from operating activities
Net cash provided by operating activities	3,644	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 capital contribution from parent	0
Net decrease in short-term borrowings with original maturities of three months or less	0	0
Repayment of long-term debt	0
Payments of obligations under finance leases	0
Other	0	0
Net cash used in financing activities	0	0
Net decrease in cash, cash equivalents and restricted cash, including cash from discontinued operations	3,644	0
Cash, cash equivalents and restricted cash, including cash from discontinued operations, beginning of period	17,791	77
Cash, cash equivalents and restricted cash, including cash from discontinued operations, end of period		77
Less: Restricted cash		0
Cash and cash equivalents	$ 21,435	$ 77	$ 17,791