Electric utility segment - Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Nov. 01, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Utility property, plant and equipment
Total property, plant and equipment, net	$ 6,060,000		$ 6,134,318
Current assets
Cash and cash equivalents	154,285		750,535		$ 215,573
Regulatory assets	44,022		53,895
Total current assets	1,540,251		2,134,326
Other long-term assets
Operating lease right-of-use assets	62,065		66,553
Total assets	8,324,861		8,931,416
Capitalization
Common stock equity	1,534,432	$ 1,505,876	1,479,089		1,085,273	$ 2,377,380	$ 2,344,841
Preferred stock of subsidiaries - not subject to mandatory redemption	34,293		34,293
Current liabilities
Current portion of long-term debt, net	143,438		109,171
Accounts payable	232,944		203,452
Interest and dividends payable	23,921		27,203
Regulatory liabilities	27,396		26,568
Wildfire tort-related claims	478,750		478,750
Other	368,930		430,824
Total current liabilities	1,439,090		1,324,591
Deferred credits and other liabilities
Operating lease liabilities	49,768		56,523
Finance lease liabilities	462,439		426,598
Regulatory liabilities	1,266,250		1,217,515
Defined benefit pension liability	23,081		23,213
Wildfire tort-related claims	1,436,250		1,436,250
Other	215,322		242,957
Total liabilities and shareholders’ equity	8,324,861		8,931,416
Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	52,108		52,019
Plant and equipment	8,552,594		8,421,501
Right-of-use assets - finance lease	489,404		447,101
Less accumulated depreciation	(3,434,285)		(3,326,624)
Construction in progress	396,343		365,709
Utility property, plant and equipment, net	6,056,164		5,959,706
Nonutility property, plant and equipment, less accumulated depreciation	2,705		2,792
Total property, plant and equipment, net	6,058,869		5,962,498
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	106,429		184,148		88,620
Advances to affiliates	0		0
Customer accounts receivable, net	187,211		199,898
Accrued unbilled revenues, net	158,053		178,721
Other accounts receivable, net	86,774		69,637
Fuel oil stock, at average cost	114,539		98,903
Materials and supplies, at average cost	131,253		118,466
Prepayments and other	55,626		151,220
Regulatory assets	44,022		53,895
Total current assets	883,907		1,054,888
Other long-term assets
Operating lease right-of-use assets	60,943		59,281
Regulatory assets	241,960		227,424
Defined benefit pension and other postretirement benefit plans asset	112,370		108,819
Investment in unconsolidated affiliate	287,250		0
Other	238,360		200,694
Total other long-term assets	940,883		596,218
Total assets	7,883,659		7,613,604
Capitalization
Common stock equity	1,521,617	$ 1,492,244	1,156,955		1,192,842	$ 2,435,282	2,409,110
Preferred stock of subsidiaries - not subject to mandatory redemption	34,293		34,293
Long-term debt, net	1,606,735		1,854,214
Total capitalization	3,162,645		3,045,462
Current liabilities
Current portion of operating lease liabilities	16,795		15,202
Current portion of long-term debt, net	124,897		47,000
Accounts payable	227,153		196,980
Interest and dividends payable	20,891		21,536
Taxes accrued, including revenue taxes	228,825		272,001
Regulatory liabilities	27,396		26,568
Wildfire tort-related claims	478,750		478,750	$ 479,000
Other	116,145		121,011
Total current liabilities	1,290,164		1,227,671
Deferred credits and other liabilities
Operating lease liabilities	48,810		49,135
Finance lease liabilities	462,439		425,625
Deferred income taxes	0		0
Regulatory liabilities	1,266,250		1,217,515
Unamortized tax credits	72,337		76,676
Defined benefit pension liability	6,418		6,428
Wildfire tort-related claims	1,436,250		1,436,250
Other	138,346		128,842
Total deferred credits and other liabilities	3,430,850		3,340,471
Total liabilities and shareholders’ equity	7,883,659		7,613,604
Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings from non-affiliates, net	49,312		48,623
Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Consolidating adjustments | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	0		0
Plant and equipment	0		0
Right-of-use assets - finance lease	0		0
Less accumulated depreciation	0		0
Construction in progress	0		0
Utility property, plant and equipment, net	0		0
Nonutility property, plant and equipment, less accumulated depreciation	0		0
Total property, plant and equipment, net	0		0
Investment in wholly owned subsidiaries, at equity	(698,333)		(680,414)
Current assets
Cash and cash equivalents	0		0		0
Advances to affiliates	(69,200)		(62,200)
Customer accounts receivable, net	0		0
Accrued unbilled revenues, net	0		0
Other accounts receivable, net	(219,825)		(249,946)
Fuel oil stock, at average cost	0		0
Materials and supplies, at average cost	0		0
Prepayments and other	(5,379)		(6,705)
Regulatory assets	0		0
Total current assets	(294,404)		(318,851)
Other long-term assets
Operating lease right-of-use assets	0		0
Regulatory assets	0		0
Defined benefit pension and other postretirement benefit plans asset	(12,711)		(11,998)
Investment in unconsolidated affiliate	0
Other	(36,337)		(33,626)
Total other long-term assets	(49,048)		(45,624)
Total assets	(1,041,785)		(1,044,889)
Capitalization
Common stock equity	(698,333)		(680,414)		(482,112)		(722,211)
Preferred stock of subsidiaries - not subject to mandatory redemption	0		0
Long-term debt, net	0		0
Total capitalization	(698,333)		(680,414)
Current liabilities
Current portion of operating lease liabilities	0		0
Current portion of long-term debt, net	0		0
Accounts payable	0		0
Interest and dividends payable	(383)		(350)
Taxes accrued, including revenue taxes	(5,379)		(6,705)
Regulatory liabilities	0		0
Wildfire tort-related claims	0		0
Other	(219,441)		(249,597)
Total current liabilities	(294,403)		(318,852)
Deferred credits and other liabilities
Operating lease liabilities	0		0
Finance lease liabilities	0		0
Deferred income taxes	(36,338)		(33,625)
Regulatory liabilities	0		0
Unamortized tax credits	0		0
Defined benefit pension liability	(12,711)		(11,998)
Wildfire tort-related claims	0		0
Other	0		0
Total deferred credits and other liabilities	(49,049)		(45,623)
Total liabilities and shareholders’ equity	(1,041,785)		(1,044,889)
Consolidating adjustments | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Consolidating adjustments | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings from non-affiliates, net	(69,200)		(62,200)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	42,860		42,860
Plant and equipment	5,576,856		5,502,198
Right-of-use assets - finance lease	360,270		360,270
Less accumulated depreciation	(2,107,311)		(2,029,719)
Construction in progress	300,883		282,150
Utility property, plant and equipment, net	4,173,558		4,157,759
Nonutility property, plant and equipment, less accumulated depreciation	1,146		1,145
Total property, plant and equipment, net	4,174,704		4,158,904
Investment in wholly owned subsidiaries, at equity	698,333		680,414
Current assets
Cash and cash equivalents	37,575		118,367		58,819
Advances to affiliates	69,200		62,200
Customer accounts receivable, net	11,661		19,050
Accrued unbilled revenues, net	0		12,738
Other accounts receivable, net	198,508		209,752
Fuel oil stock, at average cost	87,057		70,800
Materials and supplies, at average cost	75,243		69,602
Prepayments and other	31,736		110,516
Regulatory assets	32,909		36,520
Total current assets	543,889		709,545
Other long-term assets
Operating lease right-of-use assets	34,547		29,868
Regulatory assets	178,516		172,257
Defined benefit pension and other postretirement benefit plans asset	69,263		66,292
Investment in unconsolidated affiliate	287,250
Other	227,560		194,006
Total other long-term assets	797,136		462,423
Total assets	6,214,062		6,011,286
Capitalization
Common stock equity	1,521,617		1,156,955		1,192,842		2,409,110
Preferred stock of subsidiaries - not subject to mandatory redemption	22,293		22,293
Long-term debt, net	1,168,513		1,353,173
Total capitalization	2,712,423		2,532,421
Current liabilities
Current portion of operating lease liabilities	5,387		4,430
Current portion of long-term debt, net	61,949		40,000
Accounts payable	157,257		137,837
Interest and dividends payable	15,299		15,994
Taxes accrued, including revenue taxes	163,795		197,768
Regulatory liabilities	10,046		11,701
Wildfire tort-related claims	383,000		383,000
Other	91,140		103,415
Total current liabilities	937,185		942,768
Deferred credits and other liabilities
Operating lease liabilities	33,207		29,830
Finance lease liabilities	337,009		341,364
Deferred income taxes	0		0
Regulatory liabilities	892,298		864,259
Unamortized tax credits	51,531		54,950
Defined benefit pension liability	19,005		18,301
Wildfire tort-related claims	1,149,000		1,149,000
Other	82,404		78,393
Total deferred credits and other liabilities	2,564,454		2,536,097
Total liabilities and shareholders’ equity	6,214,062		6,011,286
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings from non-affiliates, net	49,312		48,623
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	5,645		5,645
Plant and equipment	1,521,914		1,501,947
Right-of-use assets - finance lease	78,377		36,074
Less accumulated depreciation	(706,390)		(691,161)
Construction in progress	39,223		31,341
Utility property, plant and equipment, net	938,769		883,846
Nonutility property, plant and equipment, less accumulated depreciation	115		115
Total property, plant and equipment, net	938,884		883,961
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	39,334		31,534		18,864
Advances to affiliates	0		0
Customer accounts receivable, net	4,613		7,245
Accrued unbilled revenues, net	1,890		4,046
Other accounts receivable, net	57,524		58,366
Fuel oil stock, at average cost	10,490		13,764
Materials and supplies, at average cost	18,282		15,506
Prepayments and other	9,277		16,662
Regulatory assets	6,065		8,211
Total current assets	147,475		155,334
Other long-term assets
Operating lease right-of-use assets	19,979		22,672
Regulatory assets	20,460		18,875
Defined benefit pension and other postretirement benefit plans asset	31,181		30,397
Investment in unconsolidated affiliate	0
Other	18,663		18,612
Total other long-term assets	90,283		90,556
Total assets	1,176,642		1,129,851
Capitalization
Common stock equity	253,516		243,964		243,878		359,790
Preferred stock of subsidiaries - not subject to mandatory redemption	7,000		7,000
Long-term debt, net	236,528		244,466
Total capitalization	497,044		495,430
Current liabilities
Current portion of operating lease liabilities	8,226		7,802
Current portion of long-term debt, net	7,993		5,000
Accounts payable	31,870		27,077
Interest and dividends payable	3,221		3,191
Taxes accrued, including revenue taxes	35,971		42,692
Regulatory liabilities	11,648		10,039
Wildfire tort-related claims	47,875		47,875
Other	29,915		35,492
Total current liabilities	176,719		179,168
Deferred credits and other liabilities
Operating lease liabilities	12,091		15,230
Finance lease liabilities	75,839		34,370
Deferred income taxes	7,230		5,368
Regulatory liabilities	229,075		222,834
Unamortized tax credits	10,308		10,757
Defined benefit pension liability	124		125
Wildfire tort-related claims	143,625		143,625
Other	24,587		22,944
Total deferred credits and other liabilities	502,879		455,253
Total liabilities and shareholders’ equity	1,176,642		1,129,851
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	3,603		3,514
Plant and equipment	1,453,824		1,417,356
Right-of-use assets - finance lease	50,757		50,757
Less accumulated depreciation	(620,584)		(605,744)
Construction in progress	56,237		52,218
Utility property, plant and equipment, net	943,837		918,101
Nonutility property, plant and equipment, less accumulated depreciation	1,444		1,532
Total property, plant and equipment, net	945,281		919,633
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	8,085		16,456		10,860
Advances to affiliates	0		0
Customer accounts receivable, net	6,641		8,941
Accrued unbilled revenues, net	0		1,890
Other accounts receivable, net	50,567		51,465
Fuel oil stock, at average cost	16,992		14,339
Materials and supplies, at average cost	37,728		33,358
Prepayments and other	19,992		30,747
Regulatory assets	5,048		9,164
Total current assets	145,053		166,360
Other long-term assets
Operating lease right-of-use assets	6,417		6,741
Regulatory assets	42,984		36,292
Defined benefit pension and other postretirement benefit plans asset	24,637		24,128
Investment in unconsolidated affiliate	0
Other	28,474		21,702
Total other long-term assets	102,512		88,863
Total assets	1,192,846		1,174,856
Capitalization
Common stock equity	288,584		282,876		238,157		362,344
Preferred stock of subsidiaries - not subject to mandatory redemption	5,000		5,000
Long-term debt, net	201,694		256,575
Total capitalization	495,278		544,451
Current liabilities
Current portion of operating lease liabilities	3,182		2,970
Current portion of long-term debt, net	54,955		2,000
Accounts payable	38,026		32,066
Interest and dividends payable	2,754		2,701
Taxes accrued, including revenue taxes	32,378		37,108
Regulatory liabilities	5,702		4,828
Wildfire tort-related claims	47,875		47,875
Other	30,930		43,913
Total current liabilities	285,002		235,661
Deferred credits and other liabilities
Operating lease liabilities	3,512		4,075
Finance lease liabilities	49,591		49,891
Deferred income taxes	29,108		28,257
Regulatory liabilities	144,877		130,422
Unamortized tax credits	10,498		10,969
Defined benefit pension liability	0		0
Wildfire tort-related claims	143,625		143,625
Other	31,355		27,505
Total deferred credits and other liabilities	412,566		394,744
Total liabilities and shareholders’ equity	1,192,846		1,174,856
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings from non-affiliates, net	69,200		62,200
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	0		0
Plant and equipment	0		0
Right-of-use assets - finance lease	0		0
Less accumulated depreciation	0		0
Construction in progress	0		0
Utility property, plant and equipment, net	0		0
Nonutility property, plant and equipment, less accumulated depreciation	0		0
Total property, plant and equipment, net	0		0
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	21,435		17,791		77
Advances to affiliates	0		0
Customer accounts receivable, net	164,296		164,662
Accrued unbilled revenues, net	156,163		160,047
Other accounts receivable, net	0		0
Fuel oil stock, at average cost	0		0
Materials and supplies, at average cost	0		0
Prepayments and other	0		0
Regulatory assets	0		0
Total current assets	341,894		342,500
Other long-term assets
Operating lease right-of-use assets	0		0
Regulatory assets	0		0
Defined benefit pension and other postretirement benefit plans asset	0		0
Investment in unconsolidated affiliate	0
Other	0		0
Total other long-term assets	0		0
Total assets	341,894		342,500
Capitalization
Common stock equity	156,233		153,574		$ 77		$ 77
Preferred stock of subsidiaries - not subject to mandatory redemption	0		0
Long-term debt, net	0		0
Total capitalization	156,233		153,574
Current liabilities
Current portion of operating lease liabilities	0		0
Current portion of long-term debt, net	0		0
Accounts payable	0		0
Interest and dividends payable	0		0
Taxes accrued, including revenue taxes	2,060		1,138
Regulatory liabilities	0		0
Wildfire tort-related claims	0		0
Other	183,601		187,788
Total current liabilities	185,661		188,926
Deferred credits and other liabilities
Operating lease liabilities	0		0
Finance lease liabilities	0		0
Deferred income taxes	0		0
Regulatory liabilities	0		0
Unamortized tax credits	0		0
Defined benefit pension liability	0		0
Wildfire tort-related claims	0		0
Other	0		0
Total deferred credits and other liabilities	0		0
Total liabilities and shareholders’ equity	341,894		342,500
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings from non-affiliates, net	0		0
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings from non-affiliates, net	$ 0		$ 0