Electric utility segment - Schedule of Consolidating Statement of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Condensed Income Statements, Captions [Line Items]
Revenues	$ 3,086,896	$ 3,219,850	$ 3,287,503
Expenses
Total expenses	2,851,574	4,926,610	3,012,511
Operating income (loss)	235,322	(1,706,760)	274,992
Allowance for equity funds used during construction	15,013	13,786	15,164
Retirement defined benefits credit—other than service costs	3,482	3,754	4,014
Allowance for borrowed funds used during construction	5,893	5,470	5,201
Interest income	36,929	19,362	9,105
Income (loss) from continuing operations before income taxes	166,929	(1,791,595)	182,300
Income tax expense (benefit)	40,648	(470,962)	34,534
Income (loss) from continuing operations	126,281	(1,424,119)	201,128
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	3,161	1,890	1,890
Net income (loss) for common stock	123,120	(1,426,009)	199,238
Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	3,071,182	3,206,700	3,269,521
Expenses
Fuel oil	947,445	1,078,045	1,211,420
Purchased power	677,654	703,371	671,769
Other operation and maintenance	620,442	609,672	533,557
Wildfire tort-related claims	0	1,875,000	0
Depreciation	256,039	251,142	243,705
Taxes, other than income taxes	289,816	301,328	306,912
Total expenses	2,791,396	4,818,558	2,967,363
Operating income (loss)	279,786	(1,611,858)	302,158
Allowance for equity funds used during construction	15,013	13,786	15,164
Equity in earnings of subsidiaries	0	0	0
Retirement defined benefits credit—other than service costs	4,135	4,137	4,303
Interest expense and other charges, net	(93,702)	(82,082)	(86,140)
Allowance for borrowed funds used during construction	5,893	5,470	5,201
Interest income	9,463	6,633	6,454
Income (loss) from continuing operations before income taxes	220,588	(1,663,914)	247,140
Income tax expense (benefit)	49,033	(439,547)	51,193
Income (loss) from continuing operations	171,555	(1,224,367)	195,947
Dividends and loss on redemption of preferred stock of subsidiaries	915	915	915
Income (loss) from continuing operations	170,640	(1,225,282)	195,032
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	2,425	1,080	1,080
Net income (loss) for common stock	168,215	(1,226,362)	193,952
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	(14,426)	(6,165)	0
Expenses
Fuel oil	0	0	0
Purchased power	0	0	0
Other operation and maintenance	(14,426)	(6,165)	0
Wildfire tort-related claims		0
Depreciation	0	0	0
Taxes, other than income taxes	0	0	0
Total expenses	(14,426)	(6,165)	0
Operating income (loss)	0	0	0
Allowance for equity funds used during construction	0	0	0
Equity in earnings of subsidiaries	(40,794)	248,004	(44,809)
Retirement defined benefits credit—other than service costs	0	0	0
Interest expense and other charges, net	5,056	5,934	805
Allowance for borrowed funds used during construction	0	0	0
Interest income	(5,056)	(5,934)	(805)
Income (loss) from continuing operations before income taxes	(40,794)	248,004	(44,809)
Income tax expense (benefit)	0	0	0
Income (loss) from continuing operations	(40,794)	248,004	(44,809)
Dividends and loss on redemption of preferred stock of subsidiaries	0	0	0
Income (loss) from continuing operations	(40,794)	248,004	(44,809)
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	0	0	0
Net income (loss) for common stock	(40,794)	248,004	(44,809)
Hawaiian Electric
Condensed Income Statements, Captions [Line Items]
Revenues	200	492	268
Expenses
Total expenses	32,997	40,382	24,228
Operating income (loss)	121,677	(1,311,072)	162,210
Retirement defined benefits credit—other than service costs	(653)	(383)	(289)
Interest income	12,591	12,729	2,651
Income (loss) from continuing operations before income taxes	113,895	(1,338,132)	131,942
Income tax expense (benefit)	(9,225)	(15,609)	(13,934)
Net income (loss) for common stock	123,120	(1,426,009)	199,238
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	2,177,043	2,283,148	2,356,478
Expenses
Fuel oil	687,314	790,004	913,801
Purchased power	500,250	517,583	486,067
Other operation and maintenance	406,295	390,111	343,462
Wildfire tort-related claims		1,500,000
Depreciation	170,255	167,909	164,150
Taxes, other than income taxes	206,127	215,137	221,664
Total expenses	1,970,241	3,580,744	2,129,144
Operating income (loss)	206,802	(1,297,596)	227,334
Allowance for equity funds used during construction	11,140	10,853	11,721
Equity in earnings of subsidiaries	40,794	(248,004)	44,809
Retirement defined benefits credit—other than service costs	3,570	3,574	3,735
Interest expense and other charges, net	(71,933)	(59,906)	(62,362)
Allowance for borrowed funds used during construction	4,654	4,300	4,081
Interest income	12,973	11,136	5,113
Income (loss) from continuing operations before income taxes	208,000	(1,575,643)	234,431
Income tax expense (benefit)	37,360	(350,361)	39,399
Income (loss) from continuing operations	170,640	(1,225,282)	195,032
Dividends and loss on redemption of preferred stock of subsidiaries	0	0	0
Income (loss) from continuing operations	170,640	(1,225,282)	195,032
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	2,425	1,080	1,080
Net income (loss) for common stock	168,215	(1,226,362)	193,952
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	458,524	483,715	464,161
Expenses
Fuel oil	102,395	121,719	105,009
Purchased power	123,090	132,086	142,837
Other operation and maintenance	105,549	102,883	85,261
Wildfire tort-related claims		187,500
Depreciation	44,971	43,855	42,541
Taxes, other than income taxes	42,763	45,025	43,095
Total expenses	418,768	633,068	418,743
Operating income (loss)	39,756	(149,353)	45,418
Allowance for equity funds used during construction	1,551	1,189	1,411
Equity in earnings of subsidiaries	0	0	0
Retirement defined benefits credit—other than service costs	663	665	667
Interest expense and other charges, net	(11,186)	(11,422)	(11,650)
Allowance for borrowed funds used during construction	424	355	451
Interest income	1,340	1,062	1,071
Income (loss) from continuing operations before income taxes	32,548	(157,504)	37,368
Income tax expense (benefit)	7,284	(41,624)	8,327
Income (loss) from continuing operations	25,264	(115,880)	29,041
Dividends and loss on redemption of preferred stock of subsidiaries	523	534	534
Income (loss) from continuing operations	24,741	(116,414)	28,507
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	0	0	0
Net income (loss) for common stock	24,741	(116,414)	28,507
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	438,098	440,432	448,882
Expenses
Fuel oil	157,736	166,322	192,610
Purchased power	54,314	53,702	42,865
Other operation and maintenance	119,069	121,693	104,834
Wildfire tort-related claims		187,500
Depreciation	40,813	39,378	37,014
Taxes, other than income taxes	40,926	41,166	42,153
Total expenses	412,858	609,761	419,476
Operating income (loss)	25,240	(169,329)	29,406
Allowance for equity funds used during construction	2,322	1,744	2,032
Equity in earnings of subsidiaries	0	0	0
Retirement defined benefits credit—other than service costs	(98)	(102)	(99)
Interest expense and other charges, net	(15,639)	(16,688)	(12,933)
Allowance for borrowed funds used during construction	815	815	669
Interest income	206	369	1,075
Income (loss) from continuing operations before income taxes	12,846	(183,191)	20,150
Income tax expense (benefit)	2,332	(48,700)	3,467
Income (loss) from continuing operations	10,514	(134,491)	16,683
Dividends and loss on redemption of preferred stock of subsidiaries	392	381	381
Income (loss) from continuing operations	10,122	(134,872)	16,302
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	0	0	0
Net income (loss) for common stock	10,122	(134,872)	16,302
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	11,943	5,570
Expenses
Fuel oil	0	0
Purchased power	0	0
Other operation and maintenance	3,955	1,150
Wildfire tort-related claims		0
Depreciation	0	0
Taxes, other than income taxes	0	0
Total expenses	3,955	1,150
Operating income (loss)	7,988	4,420
Allowance for equity funds used during construction	0	0	0
Equity in earnings of subsidiaries	0	0
Retirement defined benefits credit—other than service costs	0	0
Interest expense and other charges, net	0	0
Allowance for borrowed funds used during construction	0	0
Interest income	0
Income (loss) from continuing operations before income taxes	7,988	4,420
Income tax expense (benefit)	2,057	1,138
Income (loss) from continuing operations	5,931	3,282	$ 0
Dividends and loss on redemption of preferred stock of subsidiaries	0	0
Income (loss) from continuing operations	5,931	3,282
Dividends on and loss on redemption of preferred stock of Hawaiian Electric	0	0
Net income (loss) for common stock	$ 5,931	$ 3,282