Electric utility segment - Condensed consolidating statement of income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Condensed Income Statements, Captions [Line Items]
Revenues	$ 928,237	$ 785,068
Expenses
Total expenses	834,719	685,792
Total operating income	93,518	99,276
Allowance for equity funds used during construction	3,301	2,409
Retirement defined benefits credit (expense)—other than service costs	1,152	1,243
Allowance for borrowed funds used during construction	1,131	778
Income before income taxes	70,304	87,480
Income taxes	15,110	17,840
Net income attributable to Hawaiian Electric	55,194	69,640
Preferred stock dividends of Hawaiian Electric	473	473
Net income for common stock	54,721	69,167
Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	830,361	708,792
Expenses
Fuel oil	334,097	221,286
Purchased power	152,761	163,533
Other operation and maintenance	128,316	125,257
Depreciation	60,927	58,471
Taxes, other than income taxes	78,385	66,650
Total expenses	754,486	635,197
Total operating income	75,875	73,595
Allowance for equity funds used during construction	3,301	2,409
Equity in earnings of subsidiaries	0	0
Retirement defined benefits credit (expense)—other than service costs	1,047	990
Interest expense and other charges, net	(20,246)	(18,326)
Allowance for borrowed funds used during construction	1,131	778
Income before income taxes	61,108	59,446
Income taxes	13,600	12,538
Net income	47,508	46,908
Preferred stock dividends of subsidiaries	229	229
Net income attributable to Hawaiian Electric	47,279	46,679
Preferred stock dividends of Hawaiian Electric	270	270
Net income for common stock	47,009	46,409
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric (parent only)
Condensed Income Statements, Captions [Line Items]
Revenues	601,530	500,242
Expenses
Fuel oil	253,827	154,425
Purchased power	110,279	124,183
Other operation and maintenance	83,233	83,656
Depreciation	41,038	39,484
Taxes, other than income taxes	56,953	47,274
Total expenses	545,330	449,022
Total operating income	56,200	51,220
Allowance for equity funds used during construction	2,640	1,990
Equity in earnings of subsidiaries	11,541	13,661
Retirement defined benefits credit (expense)—other than service costs	904	855
Interest expense and other charges, net	(14,557)	(13,093)
Allowance for borrowed funds used during construction	918	651
Income before income taxes	57,646	55,284
Income taxes	10,367	8,605
Net income	47,279	46,679
Preferred stock dividends of subsidiaries	0	0
Net income attributable to Hawaiian Electric	47,279	46,679
Preferred stock dividends of Hawaiian Electric	270	270
Net income for common stock	47,009	46,409
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Condensed Income Statements, Captions [Line Items]
Revenues	115,288	108,528
Expenses
Fuel oil	27,760	25,251
Purchased power	34,086	30,712
Other operation and maintenance	21,350	20,214
Depreciation	10,635	10,351
Taxes, other than income taxes	10,737	10,032
Total expenses	104,568	96,560
Total operating income	10,720	11,968
Allowance for equity funds used during construction	284	193
Equity in earnings of subsidiaries	0	0
Retirement defined benefits credit (expense)—other than service costs	169	167
Interest expense and other charges, net	(2,831)	(2,609)
Allowance for borrowed funds used during construction	91	60
Income before income taxes	8,433	9,779
Income taxes	1,909	2,268
Net income	6,524	7,511
Preferred stock dividends of subsidiaries	134	134
Net income attributable to Hawaiian Electric	6,390	7,377
Preferred stock dividends of Hawaiian Electric	0	0
Net income for common stock	6,390	7,377
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Condensed Income Statements, Captions [Line Items]
Revenues	113,673	100,028
Expenses
Fuel oil	52,510	41,610
Purchased power	8,396	8,638
Other operation and maintenance	23,733	21,387
Depreciation	9,254	8,636
Taxes, other than income taxes	10,695	9,344
Total expenses	104,588	89,615
Total operating income	9,085	10,413
Allowance for equity funds used during construction	377	226
Equity in earnings of subsidiaries	0	0
Retirement defined benefits credit (expense)—other than service costs	(26)	(32)
Interest expense and other charges, net	(2,988)	(2,630)
Allowance for borrowed funds used during construction	122	67
Income before income taxes	6,570	8,044
Income taxes	1,324	1,665
Net income	5,246	6,379
Preferred stock dividends of subsidiaries	95	95
Net income attributable to Hawaiian Electric	5,151	6,284
Preferred stock dividends of Hawaiian Electric	0	0
Net income for common stock	5,151	6,284
Hawaiian Electric Consolidated | Reportable Legal Entities | Other subsidiaries
Condensed Income Statements, Captions [Line Items]
Revenues	0	0
Expenses
Fuel oil	0	0
Purchased power	0	0
Other operation and maintenance	0	0
Depreciation	0	0
Taxes, other than income taxes	0	0
Total expenses	0	0
Total operating income	0	0
Allowance for equity funds used during construction	0	0
Equity in earnings of subsidiaries	0	0
Retirement defined benefits credit (expense)—other than service costs	0	0
Interest expense and other charges, net	0	0
Allowance for borrowed funds used during construction	0	0
Income before income taxes	0	0
Income taxes	0	0
Net income	0	0
Preferred stock dividends of subsidiaries	0	0
Net income attributable to Hawaiian Electric	0	0
Preferred stock dividends of Hawaiian Electric	0	0
Net income for common stock	0	0
Hawaiian Electric Consolidated | Consolidating adjustments
Condensed Income Statements, Captions [Line Items]
Revenues	(130)	(6)
Expenses
Fuel oil	0	0
Purchased power	0	0
Other operation and maintenance	0	0
Depreciation	0	0
Taxes, other than income taxes	0	0
Total expenses	0	0
Total operating income	(130)	(6)
Allowance for equity funds used during construction	0	0
Equity in earnings of subsidiaries	(11,541)	(13,661)
Retirement defined benefits credit (expense)—other than service costs	0	0
Interest expense and other charges, net	130	6
Allowance for borrowed funds used during construction	0	0
Income before income taxes	(11,541)	(13,661)
Income taxes	0	0
Net income	(11,541)	(13,661)
Preferred stock dividends of subsidiaries	0	0
Net income attributable to Hawaiian Electric	(11,541)	(13,661)
Preferred stock dividends of Hawaiian Electric	0	0
Net income for common stock	$ (11,541)	$ (13,661)