Electric utility segment - Consolidating Statement of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Income Statements, Captions [Line Items]
Revenues	$ 3,682,166	$ 3,741,985	$ 2,850,379
Expenses
Total expenses	3,329,562	3,360,912	2,464,313
Operating income	352,604	381,073	386,066
Allowance for equity funds used during construction	15,164	10,574	9,534
Retirement defined benefits credit—other than service costs	4,768	4,411	5,848
Allowance for borrowed funds used during construction	5,201	3,416	3,250
Interest income	9,105	0	0
Income before income taxes	245,701	304,195	310,863
Income taxes	44,573	61,167	62,807
Net income	201,128	243,028	248,056
Preferred stock dividends of Hawaiian Electric	1,890	1,890	1,890
Net income for common stock	199,238	241,138	246,166
Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	3,269,521	3,408,587	2,539,636
Expenses
Fuel oil	1,211,420	1,265,614	644,349
Purchased power	671,769	793,584	670,494
Other operation and maintenance	533,557	497,601	475,412
Depreciation	243,705	235,424	229,469
Taxes, other than income taxes	306,912	317,173	240,354
Total expenses	2,967,363	3,109,396	2,260,078
Operating income	302,158	299,191	279,558
Allowance for equity funds used during construction	15,164	10,574	9,534
Equity in earnings of subsidiaries	0	0	0
Retirement defined benefits credit—other than service costs	4,303	3,835	3,890
Interest expense and other charges, net	(86,140)	(76,416)	(72,447)
Allowance for borrowed funds used during construction	5,201	3,416	3,250
Interest income	6,454	0	0
Income before income taxes	247,140	240,600	223,785
Income taxes	51,193	49,676	44,148
Net income (loss)	195,947	190,924	179,637
Preferred stock dividends of subsidiaries	915	915	915
Net income	195,032	190,009	178,722
Preferred stock dividends of Hawaiian Electric	1,080	1,080	1,080
Net income for common stock	193,952	188,929	177,642
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	0	(327)	(25)
Expenses
Fuel oil	0	0	0
Purchased power	0	0	0
Other operation and maintenance	0	0	0
Depreciation	0	0	0
Taxes, other than income taxes	0	0	0
Total expenses	0	0	0
Operating income	0	(327)	(25)
Allowance for equity funds used during construction	0	0	0
Equity in earnings of subsidiaries	(44,809)	(47,493)	(45,353)
Retirement defined benefits credit—other than service costs	0	0	0
Interest expense and other charges, net	805	327	25
Allowance for borrowed funds used during construction	0	0	0
Interest income	(805)
Income before income taxes	(44,809)	(47,493)	(45,353)
Income taxes	0	0	0
Net income (loss)	(44,809)	(47,493)	(45,353)
Preferred stock dividends of subsidiaries	0	0	0
Net income	(44,809)	(47,493)	(45,353)
Preferred stock dividends of Hawaiian Electric	0	0	0
Net income for common stock	(44,809)	(47,493)	(45,353)
Hawaiian Electric
Condensed Income Statements, Captions [Line Items]
Revenues	268	320	105
Expenses
Total expenses	24,228	21,981	24,934
Operating income	215,572	251,415	253,914
Retirement defined benefits credit—other than service costs	(289)	(147)	114
Interest income	2,651	0	0
Income before income taxes	185,304	229,271	235,584
Income taxes	(13,934)	(11,867)	(10,582)
Net income for common stock	199,238	241,138	246,166
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	2,356,478	2,452,969	1,793,372
Expenses
Fuel oil	913,801	917,801	442,818
Purchased power	486,067	601,235	508,642
Other operation and maintenance	343,462	326,785	313,009
Depreciation	164,150	158,725	155,607
Taxes, other than income taxes	221,664	228,843	170,604
Total expenses	2,129,144	2,233,389	1,590,680
Operating income	227,334	219,580	202,692
Allowance for equity funds used during construction	11,721	8,464	7,734
Equity in earnings of subsidiaries	44,809	47,493	45,353
Retirement defined benefits credit—other than service costs	3,735	3,296	3,348
Interest expense and other charges, net	(62,362)	(55,260)	(51,680)
Allowance for borrowed funds used during construction	4,081	2,769	2,617
Interest income	5,113
Income before income taxes	234,431	226,342	210,064
Income taxes	39,399	36,333	31,342
Net income (loss)	195,032	190,009	178,722
Preferred stock dividends of subsidiaries	0	0	0
Net income	195,032	190,009	178,722
Preferred stock dividends of Hawaiian Electric	1,080	1,080	1,080
Net income for common stock	193,952	188,929	177,642
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	464,161	485,590	381,033
Expenses
Fuel oil	105,009	133,238	80,086
Purchased power	142,837	143,636	108,997
Other operation and maintenance	85,261	85,110	79,390
Depreciation	42,541	41,404	40,201
Taxes, other than income taxes	43,095	44,685	35,499
Total expenses	418,743	448,073	344,173
Operating income	45,418	37,517	36,860
Allowance for equity funds used during construction	1,411	898	586
Equity in earnings of subsidiaries	0	0	0
Retirement defined benefits credit—other than service costs	667	666	670
Interest expense and other charges, net	(11,650)	(10,659)	(10,353)
Allowance for borrowed funds used during construction	451	277	197
Interest income	1,071
Income before income taxes	37,368	28,699	27,960
Income taxes	8,327	6,349	6,246
Net income (loss)	29,041	22,350	21,714
Preferred stock dividends of subsidiaries	534	534	534
Net income	28,507	21,816	21,180
Preferred stock dividends of Hawaiian Electric	0	0	0
Net income for common stock	28,507	21,816	21,180
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	448,882	470,355	365,256
Expenses
Fuel oil	192,610	214,575	121,445
Purchased power	42,865	48,713	52,855
Other operation and maintenance	104,834	85,706	83,013
Depreciation	37,014	35,295	33,661
Taxes, other than income taxes	42,153	43,645	34,251
Total expenses	419,476	427,934	325,225
Operating income	29,406	42,421	40,031
Allowance for equity funds used during construction	2,032	1,212	1,214
Equity in earnings of subsidiaries	0	0	0
Retirement defined benefits credit—other than service costs	(99)	(127)	(128)
Interest expense and other charges, net	(12,933)	(10,824)	(10,439)
Allowance for borrowed funds used during construction	669	370	436
Interest income	1,075
Income before income taxes	20,150	33,052	31,114
Income taxes	3,467	6,994	6,560
Net income (loss)	16,683	26,058	24,554
Preferred stock dividends of subsidiaries	381	381	381
Net income	16,302	25,677	24,173
Preferred stock dividends of Hawaiian Electric	0	0	0
Net income for common stock	$ 16,302	$ 25,677	$ 24,173