Electric utility segment - Condensed Consolidating Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2023	Sep. 30, 2022
Condensed Income Statements, Captions [Line Items]
Revenues	$ 901,873			$ 1,042,197			$ 2,725,795	$ 2,722,872
Expenses
Total expenses	826,762			940,082			2,464,187	2,434,813
Operating income (loss)	75,111			102,115			261,608	288,059
Allowance for equity funds used during construction	4,000			2,552			11,073	7,431
Retirement defined benefits credit (expense)—other than service costs	1,256			1,039			3,561	3,528
Allowance for borrowed funds used during construction	1,372			825			3,798	2,401
Income (loss) before income taxes	49,110			79,905			188,781	233,602
Income taxes	7,521			17,352			36,915	48,395
Net income (loss)	41,589			62,553			151,866	185,207
Preferred stock dividends of Hawaiian Electric	471			471			1,417	1,417
Net income for common stock	41,118	$ 54,610	$ 54,721	62,082	$ 52,541	$ 69,167	150,449	183,790
Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	794,987			955,971			2,419,539	2,483,636
Expenses
Fuel oil	267,438			383,602			881,692	874,543
Purchased power	177,795			225,209			498,990	606,827
Other operation and maintenance	142,508			121,110			407,184	371,259
Depreciation	61,165			58,711			182,781	175,921
Taxes, other than income taxes	74,723			88,290			228,034	231,288
Total expenses	723,629			876,922			2,198,681	2,259,838
Operating income (loss)	71,358			79,049			220,858	223,798
Allowance for equity funds used during construction	4,000			2,552			11,073	7,431
Equity in earnings of subsidiaries	0			0			0	0
Retirement defined benefits credit (expense)—other than service costs	1,132			895			3,227	2,876
Interest expense and other charges, net	(22,447)			(19,609)			(63,565)	(56,735)
Allowance for borrowed funds used during construction	1,372			825			3,798	2,401
Income (loss) before income taxes	55,415			63,712			175,391	179,771
Income taxes	11,456			13,450			38,126	37,967
Net income	43,959			50,262			137,265	141,804
Preferred stock dividends of subsidiaries	228			228			686	686
Net income (loss)	43,731			50,034			136,579	141,118
Preferred stock dividends of Hawaiian Electric	270			270			810	810
Net income for common stock	43,461	$ 45,299	$ 47,009	49,764	$ 44,135	$ 46,409	135,769	140,308
Consolidating adjustments | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	0			(78)			(130)	(113)
Expenses
Fuel oil	0			0			0	0
Purchased power	0			0			0	0
Other operation and maintenance	0			0			0	0
Depreciation	0			0			0	0
Taxes, other than income taxes	0			0			0	0
Total expenses	0			0			0	0
Operating income (loss)	0			(78)			(130)	(113)
Allowance for equity funds used during construction	0			0			0	0
Equity in earnings of subsidiaries	(3,005)			(10,577)			(25,960)	(36,475)
Retirement defined benefits credit (expense)—other than service costs	0			0			0	0
Interest expense and other charges, net	0			78			130	113
Allowance for borrowed funds used during construction	0			0			0	0
Income (loss) before income taxes	(3,005)			(10,577)			(25,960)	(36,475)
Income taxes	0			0			0	0
Net income	(3,005)			(10,577)			(25,960)	(36,475)
Preferred stock dividends of subsidiaries	0			0			0	0
Net income (loss)	(3,005)			(10,577)			(25,960)	(36,475)
Preferred stock dividends of Hawaiian Electric	0			0			0	0
Net income for common stock	(3,005)			(10,577)			(25,960)	(36,475)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	570,323			693,281			1,742,542	1,769,995
Expenses
Fuel oil	196,223			280,447			663,521	619,169
Purchased power	132,536			171,470			362,275	460,855
Other operation and maintenance	83,528			77,115			255,728	243,478
Depreciation	41,276			39,474			123,114	118,459
Taxes, other than income taxes	53,511			64,051			164,510	165,350
Total expenses	507,074			632,557			1,569,148	1,607,311
Operating income (loss)	63,249			60,724			173,394	162,684
Allowance for equity funds used during construction	3,005			2,063			8,604	5,999
Equity in earnings of subsidiaries	3,005			10,577			25,960	36,475
Retirement defined benefits credit (expense)—other than service costs	992			760			2,801	2,471
Interest expense and other charges, net	(16,295)			(14,221)			(45,594)	(40,833)
Allowance for borrowed funds used during construction	1,047			674			2,995	1,962
Income (loss) before income taxes	55,003			60,577			168,160	168,758
Income taxes	11,272			10,543			31,581	27,640
Net income	43,731			50,034			136,579	141,118
Preferred stock dividends of subsidiaries	0			0			0	0
Net income (loss)	43,731			50,034			136,579	141,118
Preferred stock dividends of Hawaiian Electric	270			270			810	810
Net income for common stock	43,461			49,764			135,769	140,308
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	116,192			130,858			343,554	363,888
Expenses
Fuel oil	30,956			40,540			79,187	98,856
Purchased power	30,265			37,263			101,597	106,710
Other operation and maintenance	21,351			21,882			64,367	63,427
Depreciation	10,635			10,350			31,906	31,053
Taxes, other than income taxes	10,857			12,026			31,983	33,436
Total expenses	104,064			122,061			309,040	333,482
Operating income (loss)	12,128			8,797			34,514	30,406
Allowance for equity funds used during construction	366			206			1,004	616
Equity in earnings of subsidiaries	0			0			0	0
Retirement defined benefits credit (expense)—other than service costs	163			166			500	500
Interest expense and other charges, net	(2,988)			(2,716)			(8,794)	(7,967)
Allowance for borrowed funds used during construction	117			63			321	190
Income (loss) before income taxes	9,786			6,516			27,545	23,745
Income taxes	2,234			1,424			6,261	5,351
Net income	7,552			5,092			21,284	18,394
Preferred stock dividends of subsidiaries	133			133			400	400
Net income (loss)	7,419			4,959			20,884	17,994
Preferred stock dividends of Hawaiian Electric	0			0			0	0
Net income for common stock	7,419			4,959			20,884	17,994
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	108,472			131,910			333,573	349,866
Expenses
Fuel oil	40,259			62,615			138,984	156,518
Purchased power	14,994			16,476			35,118	39,262
Other operation and maintenance	37,629			22,113			87,089	64,354
Depreciation	9,254			8,887			27,761	26,409
Taxes, other than income taxes	10,355			12,213			31,541	32,502
Total expenses	112,491			122,304			320,493	319,045
Operating income (loss)	(4,019)			9,606			13,080	30,821
Allowance for equity funds used during construction	629			283			1,465	816
Equity in earnings of subsidiaries	0			0			0	0
Retirement defined benefits credit (expense)—other than service costs	(23)			(31)			(74)	(95)
Interest expense and other charges, net	(3,164)			(2,750)			(9,307)	(8,048)
Allowance for borrowed funds used during construction	208			88			482	249
Income (loss) before income taxes	(6,369)			7,196			5,646	23,743
Income taxes	(2,050)			1,483			284	4,976
Net income	(4,319)			5,713			5,362	18,767
Preferred stock dividends of subsidiaries	95			95			286	286
Net income (loss)	(4,414)			5,618			5,076	18,481
Preferred stock dividends of Hawaiian Electric	0			0			0	0
Net income for common stock	(4,414)			5,618			5,076	18,481
Other subsidiary | 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
Depreciation	0			0			0	0
Taxes, other than income taxes	0			0			0	0
Total expenses	0			0			0	0
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
Income (loss) before income taxes	0			0			0	0
Income taxes	0			0			0	0
Net income	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 for common stock	$ 0			$ 0			$ 0	$ 0