Electric utility segment - Condensed Consolidating Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022
Condensed Income Statements, Captions [Line Items]
Revenues	$ 895,685		$ 895,607		$ 1,823,922	$ 1,680,675
Expenses
Total expenses	802,706		808,939		1,637,425	1,494,731
Operating income - bank	92,979		86,668		186,497	185,944
Allowance for equity funds used during construction	3,772		2,470		7,073	4,879
Retirement defined benefits credit (expense)—other than service costs	1,153		1,246		2,305	2,489
Allowance for borrowed funds used during construction	1,295		798		2,426	1,576
Income before income taxes	69,367		66,217		139,671	153,697
Income taxes	14,284		13,203		29,394	31,043
Net income attributable to Hawaiian Electric	55,083		53,014		110,277	122,654
Preferred stock dividends of Hawaiian Electric	473		473		946	946
Net income for common stock	54,610	$ 54,721	52,541	$ 69,167	109,331	121,708
Hawaiian Electric Consolidated
Condensed Income Statements, Captions [Line Items]
Revenues	794,191		818,873		1,624,552	1,527,665
Expenses
Fuel oil	280,157		269,655		614,254	490,941
Purchased power	168,434		218,085		321,195	381,618
Other operation and maintenance	136,360		124,892		264,676	250,149
Depreciation	60,689		58,739		121,616	117,210
Taxes, other than income taxes	74,926		76,348		153,311	142,998
Total expenses	720,566		747,719		1,475,052	1,382,916
Operating income - bank	73,625		71,154		149,500	144,749
Allowance for equity funds used during construction	3,772		2,470		7,073	4,879
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	1,048		991		2,095	1,981
Interest expense and other charges, net	(20,872)		(18,800)		(41,118)	(37,126)
Allowance for borrowed funds used during construction	1,295		798		2,426	1,576
Income before income taxes	58,868		56,613		119,976	116,059
Income taxes	13,070		11,979		26,670	24,517
Net income	45,798		44,634		93,306	91,542
Preferred stock dividends of subsidiaries	229		229		458	458
Net income attributable to Hawaiian Electric	45,569		44,405		92,848	91,084
Preferred stock dividends of Hawaiian Electric	270		270		540	540
Net income for common stock	45,299	$ 47,009	44,135	$ 46,409	92,308	90,544
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric
Condensed Income Statements, Captions [Line Items]
Revenues	570,689		576,472		1,172,219	1,076,714
Expenses
Fuel oil	213,471		184,297		467,298	338,722
Purchased power	119,460		165,202		229,739	289,385
Other operation and maintenance	88,967		82,707		172,200	166,363
Depreciation	40,800		39,501		81,838	78,985
Taxes, other than income taxes	54,046		54,025		110,999	101,299
Total expenses	516,744		525,732		1,062,074	974,754
Operating income - bank	53,945		50,740		110,145	101,960
Allowance for equity funds used during construction	2,959		1,946		5,599	3,936
Equity in earnings of subsidiaries	11,414		12,237		22,955	25,898
Retirement defined benefits credit (expense)—other than service costs	905		856		1,809	1,711
Interest expense and other charges, net	(14,742)		(13,519)		(29,299)	(26,612)
Allowance for borrowed funds used during construction	1,030		637		1,948	1,288
Income before income taxes	55,511		52,897		113,157	108,181
Income taxes	9,942		8,492		20,309	17,097
Net income	45,569		44,405		92,848	91,084
Preferred stock dividends of subsidiaries	0		0		0	0
Net income attributable to Hawaiian Electric	45,569		44,405		92,848	91,084
Preferred stock dividends of Hawaiian Electric	270		270		540	540
Net income for common stock	45,299		44,135		92,308	90,544
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Condensed Income Statements, Captions [Line Items]
Revenues	112,074		124,502		227,362	233,030
Expenses
Fuel oil	20,471		33,065		48,231	58,316
Purchased power	37,246		38,735		71,332	69,447
Other operation and maintenance	21,666		21,331		43,016	41,545
Depreciation	10,636		10,352		21,271	20,703
Taxes, other than income taxes	10,389		11,378		21,126	21,410
Total expenses	100,408		114,861		204,976	211,421
Operating income - bank	11,666		9,641		22,386	21,609
Allowance for equity funds used during construction	354		217		638	410
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	168		167		337	334
Interest expense and other charges, net	(2,975)		(2,642)		(5,806)	(5,251)
Allowance for borrowed funds used during construction	113		67		204	127
Income before income taxes	9,326		7,450		17,759	17,229
Income taxes	2,118		1,659		4,027	3,927
Net income	7,208		5,791		13,732	13,302
Preferred stock dividends of subsidiaries	133		133		267	267
Net income attributable to Hawaiian Electric	7,075		5,658		13,465	13,035
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income for common stock	7,075		5,658		13,465	13,035
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Condensed Income Statements, Captions [Line Items]
Revenues	111,428		117,928		225,101	217,956
Expenses
Fuel oil	46,215		52,293		98,725	93,903
Purchased power	11,728		14,148		20,124	22,786
Other operation and maintenance	25,727		20,854		49,460	42,241
Depreciation	9,253		8,886		18,507	17,522
Taxes, other than income taxes	10,491		10,945		21,186	20,289
Total expenses	103,414		107,126		208,002	196,741
Operating income - bank	8,014		10,802		17,099	21,215
Allowance for equity funds used during construction	459		307		836	533
Equity in earnings of subsidiaries	0		0		0	0
Retirement defined benefits credit (expense)—other than service costs	(25)		(32)		(51)	(64)
Interest expense and other charges, net	(3,155)		(2,668)		(6,143)	(5,298)
Allowance for borrowed funds used during construction	152		94		274	161
Income before income taxes	5,445		8,503		12,015	16,547
Income taxes	1,010		1,828		2,334	3,493
Net income	4,435		6,675		9,681	13,054
Preferred stock dividends of subsidiaries	96		96		191	191
Net income attributable to Hawaiian Electric	4,339		6,579		9,490	12,863
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income for common stock	4,339		6,579		9,490	12,863
Hawaiian Electric Consolidated | Reportable Legal Entities | Other subsidiary
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 - bank	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 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 attributable to Hawaiian Electric	0		0		0	0
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income for common stock	0		0		0	0
Hawaiian Electric Consolidated | Consolidating adjustments
Condensed Income Statements, Captions [Line Items]
Revenues	0		(29)		(130)	(35)
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 - bank	0		(29)		(130)	(35)
Allowance for equity funds used during construction	0		0		0	0
Equity in earnings of subsidiaries	(11,414)		(12,237)		(22,955)	(25,898)
Retirement defined benefits credit (expense)—other than service costs	0		0		0	0
Interest expense and other charges, net	0		29		130	35
Allowance for borrowed funds used during construction	0		0		0	0
Income before income taxes	(11,414)		(12,237)		(22,955)	(25,898)
Income taxes	0		0		0	0
Net income	(11,414)		(12,237)		(22,955)	(25,898)
Preferred stock dividends of subsidiaries	0		0		0	0
Net income attributable to Hawaiian Electric	(11,414)		(12,237)		(22,955)	(25,898)
Preferred stock dividends of Hawaiian Electric	0		0		0	0
Net income for common stock	$ (11,414)		$ (12,237)		$ (22,955)	$ (25,898)