Electric utility segment - Condensed Consolidating Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Condensed Income Statements, Captions [Line Items]
Revenues	$ 897,360		$ 895,685		$ 1,794,518	$ 1,823,922
Expenses
Total expenses	2,616,335		802,706		3,437,074	1,637,425
Total operating income (loss)	(1,718,975)		92,979		(1,642,556)	186,497
Allowance for equity funds used during construction	3,336		3,772		6,976	7,073
Retirement defined benefits credit (expense)—other than service costs	1,281		1,153		2,563	2,305
Allowance for borrowed funds used during construction	1,344		1,295		2,730	2,426
Interest income	3,134		0		6,267	0
Loss before income taxes	(1,742,280)		69,367		(1,688,011)	139,671
Income tax expense (benefit)	(447,269)		14,284		(435,595)	29,394
Net income (loss)	(1,295,011)		55,083		(1,252,416)	110,277
Preferred stock dividends of Hawaiian Electric	473		473		946	946
Net income (loss) for common stock	(1,295,484)	$ 42,122	54,610	$ 54,721	(1,253,362)	109,331
Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	792,331		794,191		1,580,909	1,624,552
Expenses
Fuel oil	258,652		280,157		542,948	614,254
Purchased power	181,328		168,434		341,145	321,195
Other operation and maintenance	147,561		136,360		291,451	264,676
Wildfire tort-related claims	1,712,000		0		1,712,000	0
Depreciation	62,812		60,689		125,624	121,616
Taxes, other than income taxes	74,418		74,926		148,826	153,311
Total expenses	2,436,771		720,566		3,161,994	1,475,052
Total operating income (loss)	(1,644,440)		73,625		(1,581,085)	149,500
Allowance for equity funds used during construction	3,336		3,772		6,976	7,073
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	1,072		1,048		2,144	2,095
Interest expense and other charges, net	(21,417)		(20,872)		(41,402)	(41,118)
Allowance for borrowed funds used during construction	1,344		1,295		2,730	2,426
Interest income	1,452		0		2,884	0
Loss before income taxes	(1,658,653)		58,868		(1,607,753)	119,976
Income tax expense (benefit)	(429,758)		13,070		(418,578)	26,670
Net income (loss)	(1,228,895)		45,798		(1,189,175)	93,306
Preferred stock dividends of subsidiaries	229		229		458	458
Net income (loss)	(1,229,124)		45,569		(1,189,633)	92,848
Preferred stock dividends of Hawaiian Electric	270		270		540	540
Net income (loss) for common stock	(1,229,394)	$ 39,221	45,299	$ 47,009	(1,190,173)	92,308
Reportable Legal Entities | Hawaiian Electric Consolidated
Expenses
Interest income					2,884
Consolidating adjustments | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	0		0		0	(130)
Expenses
Fuel oil	0		0		0	0
Purchased power	0		0		0	0
Other operation and maintenance	0		0		0	0
Wildfire tort-related claims	0				0
Depreciation	0		0		0	0
Taxes, other than income taxes	0		0		0	0
Total expenses	0		0		0	0
Total operating income (loss)	0		0		0	(130)
Allowance for equity funds used during construction	0		0		0	0
Equity in earnings of subsidiaries	246,099		(11,414)		240,075	(22,955)
Retirement defined benefits credit (expense)—other than service costs	0		0		0	0
Interest expense and other charges, net	1,833		0		3,285	130
Allowance for borrowed funds used during construction	0		0		0	0
Interest income	(1,833)				(3,285)
Loss before income taxes	246,099		(11,414)		240,075	(22,955)
Income tax expense (benefit)	0		0		0	0
Net income (loss)	246,099		(11,414)		240,075	(22,955)
Preferred stock dividends of subsidiaries	0		0		0	0
Net income (loss)	246,099		(11,414)		240,075	(22,955)
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income (loss) for common stock	246,099		(11,414)		240,075	(22,955)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	564,628		570,689		1,128,808	1,172,219
Expenses
Fuel oil	187,386		213,471		397,585	467,298
Purchased power	137,139		119,460		254,657	229,739
Other operation and maintenance	93,717		88,967		184,601	172,200
Wildfire tort-related claims	1,369,600				1,369,600
Depreciation	42,003		40,800		84,007	81,838
Taxes, other than income taxes	53,214		54,046		106,623	110,999
Total expenses	1,883,059		516,744		2,397,073	1,062,074
Total operating income (loss)	(1,318,431)		53,945		(1,268,265)	110,145
Allowance for equity funds used during construction	2,578		2,959		5,399	5,599
Equity in earnings of subsidiaries	(246,099)		11,414		(240,075)	22,955
Retirement defined benefits credit (expense)—other than service costs	928		905		1,855	1,809
Interest expense and other charges, net	(15,717)		(14,742)		(30,009)	(29,299)
Allowance for borrowed funds used during construction	1,034		1,030		2,113	1,948
Interest income	2,972				5,635
Loss before income taxes	(1,572,735)		55,511		(1,523,347)	113,157
Income tax expense (benefit)	(343,611)		9,942		(333,714)	20,309
Net income (loss)	(1,229,124)		45,569		(1,189,633)	92,848
Preferred stock dividends of subsidiaries	0		0		0	0
Net income (loss)	(1,229,124)		45,569		(1,189,633)	92,848
Preferred stock dividends of Hawaiian Electric	270		270		540	540
Net income (loss) for common stock	(1,229,394)		45,299		(1,190,173)	92,308
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	117,663		112,074		235,272	227,362
Expenses
Fuel oil	28,941		20,471		60,126	48,231
Purchased power	31,068		37,246		63,124	71,332
Other operation and maintenance	24,544		21,666		49,134	43,016
Wildfire tort-related claims	171,200				171,200
Depreciation	10,964		10,636		21,928	21,271
Taxes, other than income taxes	10,943		10,389		21,900	21,126
Total expenses	277,660		100,408		387,412	204,976
Total operating income (loss)	(159,997)		11,666		(152,140)	22,386
Allowance for equity funds used during construction	288		354		637	638
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	168		168		336	337
Interest expense and other charges, net	(2,974)		(2,975)		(5,888)	(5,806)
Allowance for borrowed funds used during construction	85		113		192	204
Interest income	241				396
Loss before income taxes	(162,189)		9,326		(156,467)	17,759
Income tax expense (benefit)	(42,027)		2,118		(40,829)	4,027
Net income (loss)	(120,162)		7,208		(115,638)	13,732
Preferred stock dividends of subsidiaries	133		133		267	267
Net income (loss)	(120,295)		7,075		(115,905)	13,465
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income (loss) for common stock	(120,295)		7,075		(115,905)	13,465
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	110,040		111,428		216,829	225,101
Expenses
Fuel oil	42,325		46,215		85,237	98,725
Purchased power	13,121		11,728		23,364	20,124
Other operation and maintenance	29,300		25,727		57,716	49,460
Wildfire tort-related claims	171,200				171,200
Depreciation	9,845		9,253		19,689	18,507
Taxes, other than income taxes	10,261		10,491		20,303	21,186
Total expenses	276,052		103,414		377,509	208,002
Total operating income (loss)	(166,012)		8,014		(160,680)	17,099
Allowance for equity funds used during construction	470		459		940	836
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	(24)		(25)		(47)	(51)
Interest expense and other charges, net	(4,559)		(3,155)		(8,790)	(6,143)
Allowance for borrowed funds used during construction	225		152		425	274
Interest income	72				138
Loss before income taxes	(169,828)		5,445		(168,014)	12,015
Income tax expense (benefit)	(44,120)		1,010		(44,035)	2,334
Net income (loss)	(125,708)		4,435		(123,979)	9,681
Preferred stock dividends of subsidiaries	96		96		191	191
Net income (loss)	(125,804)		4,339		(124,170)	9,490
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income (loss) for common stock	(125,804)		4,339		(124,170)	9,490
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	0		0		0	0
Expenses
Fuel oil	0		0		0	0
Purchased power	0		0		0	0
Other operation and maintenance	0		0		0	0
Wildfire tort-related claims	0				0
Depreciation	0		0		0	0
Taxes, other than income taxes	0		0		0	0
Total expenses	0		0		0	0
Total operating income (loss)	0		0		0	0
Allowance for equity funds used during construction	0		0		0	0
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	0		0		0	0
Interest expense and other charges, net	0		0		0	0
Allowance for borrowed funds used during construction	0		0		0	0
Interest income	0
Loss before income taxes	0		0		0	0
Income tax expense (benefit)	0		0		0	0
Net income (loss)	0		0		0	0
Preferred stock dividends of subsidiaries	0		0		0	0
Net income (loss)	0		0		0	0
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income (loss) for common stock	$ 0		$ 0		0	$ 0
Other subsidiaries | Consolidating adjustments | Hawaiian Electric Consolidated
Expenses
Interest income					$ 0