Electric utility segment - Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Nov. 01, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Utility property, plant and equipment
Right-of-use assets - finance lease	$ 448,527		$ 342,834
Total property, plant and equipment, net	6,134,318		5,963,084
Current assets
Cash and cash equivalents	750,535		244,091	$ 43,728
Restricted cash	492,317		15,028
Accounts receivable and unbilled revenues, net	457,171		546,704
Regulatory assets	53,895		68,453
Other long-term assets
Operating lease right-of-use-assets	66,553		79,686
Regulatory assets	227,424		226,351
Other	368,795		202,358
Total assets	8,931,416		17,243,821
Capitalization
Total shareholders’ equity	1,479,089		2,344,841	2,202,499	$ 2,390,884
Cumulative preferred stock – not subject to mandatory redemption	34,293		34,293
Current liabilities
Current portion of long-term debt, net	109,171		16,496
Accounts payable	203,452		198,885
Regulatory liabilities	26,568		36,559
Wildfire tort-related claims	478,750		75,000
Other	430,824		403,414
Noncurrent liabilities:
Operating lease liabilities	56,523		69,972
Finance lease liabilities	426,598		331,262
Deferred income taxes	0		402,246
Regulatory liabilities	1,217,515		1,114,131
Defined benefit plans liability	23,213		78,200
Wildfire tort-related claims (Note 2)	1,436,250		0
Other	242,957		247,637
Total capitalization and liabilities	8,931,416		17,243,821
Hawaiian Electric Company, Inc. and Subsidiaries
Utility property, plant and equipment
Land	52,019		52,098
Plant and equipment	8,421,501		8,232,810
Right-of-use assets - finance lease	447,101		342,174
Less accumulated depreciation	(3,326,624)		(3,197,514)
Construction in progress	365,709		320,223
Utility property, plant and equipment, net	5,959,706		5,749,791
Nonutility property, plant and equipment, less accumulated depreciation	2,792		6,942
Total property, plant and equipment, net	5,962,498		5,756,733
Investment in wholly-owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	184,148		106,077	39,242
Restricted cash	0		2,000
Advances to affiliates	0		0
Accounts receivable and unbilled revenues, net	199,898		244,309
Accrued unbilled revenues, net	178,721		185,644
Other accounts receivable, net	69,637		111,519
Fuel oil stock, at average cost	98,903		148,237
Materials and supplies, at average cost	118,466		114,433
Prepayments and other	151,220		58,491
Regulatory assets	53,895		68,453
Total current assets	1,054,888		1,039,163
Other long-term assets
Operating lease right-of-use-assets	59,281		71,877
Regulatory assets	227,424		226,351
Defined benefit pension and other postretirement benefit plans asset	108,819		67,568
Other	200,694		121,862
Total other long-term assets	596,218		487,658
Total assets	7,613,604		7,283,554
Capitalization
Total shareholders’ equity	1,156,955		2,409,110	2,344,170	2,261,899
Cumulative preferred stock – not subject to mandatory redemption	34,293		34,293
Long-term debt, net	1,854,214		1,934,277
Total capitalization	3,045,462		4,377,680
Current liabilities
Current portion of operating lease liabilities	15,202		16,617
Current portion of long-term debt, net	47,000		0
Accounts payable	196,980		191,040
Interest and preferred dividends payable	21,536		22,882
Taxes accrued, including revenue taxes	272,001		291,942
Regulatory liabilities	26,568		36,559
Wildfire tort-related claims	478,750	$ 479,000	75,000
Other	121,011		96,436
Total current liabilities	1,227,671		730,476
Noncurrent liabilities:
Operating lease liabilities	49,135		62,098
Finance lease liabilities	425,625		330,978
Deferred income taxes	0		399,001
Regulatory liabilities	1,217,515		1,114,131
Unamortized tax credits	76,676		84,312
Defined benefit plans liability	6,428		60,671
Wildfire tort-related claims (Note 2)	1,436,250		0
Other	128,842		124,207
Total deferred credits and other liabilities	3,340,471		2,175,398
Total capitalization and liabilities	7,613,604		7,283,554
Hawaiian Electric Company, Inc. and Subsidiaries | Nonrelated Party
Current liabilities
Short-term borrowings	48,623		0
Hawaiian Electric Company, Inc. and Subsidiaries | Affiliated Entity
Current liabilities
Short-term borrowings	0		0
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries
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	(680,414)		(722,211)
Current assets
Cash and cash equivalents	0		0	0
Restricted cash			0
Advances to affiliates	(62,200)		(70,500)
Accounts receivable and unbilled revenues, net	0		0
Accrued unbilled revenues, net	0		0
Other accounts receivable, net	(249,946)		(77,480)
Fuel oil stock, at average cost	0		0
Materials and supplies, at average cost	0		0
Prepayments and other	(6,705)		(1,638)
Regulatory assets	0		0
Total current assets	(318,851)		(149,618)
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	(11,998)		(14,171)
Other	(33,626)		0
Total other long-term assets	(45,624)		(14,171)
Total assets	(1,044,889)		(886,000)
Capitalization
Total shareholders’ equity	(680,414)		(722,211)	(701,833)	(676,237)
Cumulative preferred stock – not subject to mandatory redemption	0		0
Long-term debt, net	0		0
Total capitalization	(680,414)		(722,211)
Current liabilities
Current portion of operating lease liabilities	0		0
Current portion of long-term debt, net	0
Accounts payable	0		0
Interest and preferred dividends payable	(350)		(375)
Taxes accrued, including revenue taxes	(6,705)		(1,638)
Regulatory liabilities	0		0
Wildfire tort-related claims	0		0
Other	(249,597)		(77,105)
Total current liabilities	(318,852)		(149,618)
Noncurrent liabilities:
Operating lease liabilities	0		0
Finance lease liabilities	0		0
Deferred income taxes	(33,625)		0
Regulatory liabilities	0		0
Unamortized tax credits	0		0
Defined benefit plans liability	(11,998)		(14,171)
Wildfire tort-related claims (Note 2)	0
Other	0		0
Total deferred credits and other liabilities	(45,623)		(14,171)
Total capitalization and liabilities	(1,044,889)		(886,000)
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries | Nonrelated Party
Current liabilities
Short-term borrowings	0
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries | Affiliated Entity
Current liabilities
Short-term borrowings	(62,200)		(70,500)
Hawaiian Electric
Utility property, plant and equipment
Total property, plant and equipment, net	1,300		1,495
Current assets
Cash and cash equivalents	564,184		136,510	611
Total current assets	592,238		165,353
Other long-term assets
Total assets	2,358,877		3,216,333
Capitalization
Total shareholders’ equity	1,479,089		2,344,841
Current liabilities
Current portion of long-term debt, net	49,962		0
Accounts payable	4,982		8,272
Other	69,295		51,938
Total current liabilities	127,501		63,607
Noncurrent liabilities:
Other	2,575		4,004
Total capitalization and liabilities	2,358,877		3,216,333
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Utility property, plant and equipment
Land	42,860		42,859
Plant and equipment	5,502,198		5,398,281
Right-of-use assets - finance lease	360,270		306,099
Less accumulated depreciation	(2,029,719)		(1,925,660)
Construction in progress	282,150		247,836
Utility property, plant and equipment, net	4,157,759		4,069,415
Nonutility property, plant and equipment, less accumulated depreciation	1,145		5,295
Total property, plant and equipment, net	4,158,904		4,074,710
Investment in wholly-owned subsidiaries, at equity	680,414		722,211
Current assets
Cash and cash equivalents	118,367		89,755	27,579
Restricted cash			2,000
Advances to affiliates	62,200		70,500
Accounts receivable and unbilled revenues, net	19,050		172,747
Accrued unbilled revenues, net	12,738		136,367
Other accounts receivable, net	209,752		143,160
Fuel oil stock, at average cost	70,800		108,228
Materials and supplies, at average cost	69,602		64,334
Prepayments and other	110,516		40,767
Regulatory assets	36,520		58,920
Total current assets	709,545		886,778
Other long-term assets
Operating lease right-of-use-assets	29,868		34,856
Regulatory assets	172,257		189,417
Defined benefit pension and other postretirement benefit plans asset	66,292		50,743
Other	194,006		83,290
Total other long-term assets	462,423		358,306
Total assets	6,011,286		6,042,005
Capitalization
Total shareholders’ equity	1,156,955		2,409,110	2,344,170	2,261,899
Cumulative preferred stock – not subject to mandatory redemption	22,293		22,293
Long-term debt, net	1,353,173		1,426,516
Total capitalization	2,532,421		3,857,919
Current liabilities
Current portion of operating lease liabilities	4,430		6,788
Current portion of long-term debt, net	40,000
Accounts payable	137,837		136,102
Interest and preferred dividends payable	15,994		17,085
Taxes accrued, including revenue taxes	197,768		211,840
Regulatory liabilities	11,701		20,013
Wildfire tort-related claims	383,000		75,000
Other	103,415		90,131
Total current liabilities	942,768		556,959
Noncurrent liabilities:
Operating lease liabilities	29,830		34,262
Finance lease liabilities	341,364		295,935
Deferred income taxes	0		280,029
Regulatory liabilities	864,259		803,404
Unamortized tax credits	54,950		61,130
Defined benefit plans liability	18,301		74,842
Wildfire tort-related claims (Note 2)	1,149,000
Other	78,393		77,525
Total deferred credits and other liabilities	2,536,097		1,627,127
Total capitalization and liabilities	6,011,286		6,042,005
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Nonrelated Party
Current liabilities
Short-term borrowings	48,623
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Affiliated Entity
Current liabilities
Short-term borrowings	0		0
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Utility property, plant and equipment
Land	5,645		5,645
Plant and equipment	1,501,947		1,459,639
Right-of-use assets - finance lease	36,074		36,075
Less accumulated depreciation	(691,161)		(666,581)
Construction in progress	31,341		33,488
Utility property, plant and equipment, net	883,846		868,266
Nonutility property, plant and equipment, less accumulated depreciation	115		115
Total property, plant and equipment, net	883,961		868,381
Investment in wholly-owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	31,534		10,658	5,092
Restricted cash			0
Advances to affiliates	0		0
Accounts receivable and unbilled revenues, net	7,245		38,216
Accrued unbilled revenues, net	4,046		25,102
Other accounts receivable, net	58,366		13,318
Fuel oil stock, at average cost	13,764		17,968
Materials and supplies, at average cost	15,506		14,397
Prepayments and other	16,662		7,724
Regulatory assets	8,211		5,771
Total current assets	155,334		133,154
Other long-term assets
Operating lease right-of-use-assets	22,672		27,470
Regulatory assets	18,875		13,575
Defined benefit pension and other postretirement benefit plans asset	30,397		17,827
Other	18,612		18,612
Total other long-term assets	90,556		77,484
Total assets	1,129,851		1,079,019
Capitalization
Total shareholders’ equity	243,964		359,790	344,720	332,900
Cumulative preferred stock – not subject to mandatory redemption	7,000		7,000
Long-term debt, net	244,466		249,339
Total capitalization	495,430		616,129
Current liabilities
Current portion of operating lease liabilities	7,802		7,025
Current portion of long-term debt, net	5,000
Accounts payable	27,077		29,418
Interest and preferred dividends payable	3,191		3,098
Taxes accrued, including revenue taxes	42,692		43,932
Regulatory liabilities	10,039		8,508
Wildfire tort-related claims	47,875		0
Other	35,492		33,240
Total current liabilities	179,168		125,221
Noncurrent liabilities:
Operating lease liabilities	15,230		20,792
Finance lease liabilities	34,370		35,043
Deferred income taxes	5,368		51,661
Regulatory liabilities	222,834		199,173
Unamortized tax credits	10,757		11,650
Defined benefit plans liability	125		0
Wildfire tort-related claims (Note 2)	143,625
Other	22,944		19,350
Total deferred credits and other liabilities	455,253		337,669
Total capitalization and liabilities	1,129,851		1,079,019
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Nonrelated Party
Current liabilities
Short-term borrowings	0
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Affiliated Entity
Current liabilities
Short-term borrowings	0		0
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Utility property, plant and equipment
Land	3,514		3,594
Plant and equipment	1,417,356		1,374,890
Right-of-use assets - finance lease	50,757		0
Less accumulated depreciation	(605,744)		(605,273)
Construction in progress	52,218		38,899
Utility property, plant and equipment, net	918,101		812,110
Nonutility property, plant and equipment, less accumulated depreciation	1,532		1,532
Total property, plant and equipment, net	919,633		813,642
Investment in wholly-owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	16,456		5,587	6,494
Restricted cash			0
Advances to affiliates	0		0
Accounts receivable and unbilled revenues, net	8,941		33,346
Accrued unbilled revenues, net	1,890		24,175
Other accounts receivable, net	51,465		32,521
Fuel oil stock, at average cost	14,339		22,041
Materials and supplies, at average cost	33,358		35,702
Prepayments and other	30,747		11,638
Regulatory assets	9,164		3,762
Total current assets	166,360		168,772
Other long-term assets
Operating lease right-of-use-assets	6,741		9,551
Regulatory assets	36,292		23,359
Defined benefit pension and other postretirement benefit plans asset	24,128		13,169
Other	21,702		19,960
Total other long-term assets	88,863		66,039
Total assets	1,174,856		1,048,453
Capitalization
Total shareholders’ equity	282,876		362,344	357,036	343,260
Cumulative preferred stock – not subject to mandatory redemption	5,000		5,000
Long-term debt, net	256,575		258,422
Total capitalization	544,451		625,766
Current liabilities
Current portion of operating lease liabilities	2,970		2,804
Current portion of long-term debt, net	2,000
Accounts payable	32,066		25,520
Interest and preferred dividends payable	2,701		3,074
Taxes accrued, including revenue taxes	37,108		37,808
Regulatory liabilities	4,828		8,038
Wildfire tort-related claims	47,875		0
Other	43,913		50,170
Total current liabilities	235,661		197,914
Noncurrent liabilities:
Operating lease liabilities	4,075		7,044
Finance lease liabilities	49,891		0
Deferred income taxes	28,257		67,311
Regulatory liabilities	130,422		111,554
Unamortized tax credits	10,969		11,532
Defined benefit plans liability	0		0
Wildfire tort-related claims (Note 2)	143,625
Other	27,505		27,332
Total deferred credits and other liabilities	394,744		224,773
Total capitalization and liabilities	1,174,856		1,048,453
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Nonrelated Party
Current liabilities
Short-term borrowings	0
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Affiliated Entity
Current liabilities
Short-term borrowings	62,200		70,500
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
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	17,791		77	77
Restricted cash			0
Advances to affiliates	0		0
Accounts receivable and unbilled revenues, net	164,662		0
Accrued unbilled revenues, net	160,047		0
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	342,500		77
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
Other	0		0
Total other long-term assets	0		0
Total assets	342,500		77
Capitalization
Total shareholders’ equity	153,574		77	$ 77	$ 77
Cumulative preferred stock – not subject to mandatory redemption	0		0
Long-term debt, net	0		0
Total capitalization	153,574		77
Current liabilities
Current portion of operating lease liabilities	0		0
Current portion of long-term debt, net	0
Accounts payable	0		0
Interest and preferred dividends payable	0		0
Taxes accrued, including revenue taxes	1,138		0
Regulatory liabilities	0		0
Wildfire tort-related claims	0		0
Other	187,788		0
Total current liabilities	188,926		0
Noncurrent 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 plans liability	0		0
Wildfire tort-related claims (Note 2)	0
Other	0		0
Total deferred credits and other liabilities	0		0
Total capitalization and liabilities	342,500		77
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Nonrelated Party
Current liabilities
Short-term borrowings	0
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries | Affiliated Entity
Current liabilities
Short-term borrowings	$ 0		$ 0