Electric utility segment - Condensed Consolidating Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Utility property, plant and equipment
Total property, plant and equipment, net	$ 5,917,342			$ 5,687,003
Current assets
Cash and cash equivalents	667,129			199,877	$ 175,280
Restricted cash	15,164			5,050	3,898
Other long-term assets
Operating lease right-of-use assets	99,466			115,684
Total assets	16,991,818			16,284,244
Capitalization
Common stock equity	2,224,354	$ 2,249,377	$ 2,237,955	2,202,499	2,162,922	$ 2,233,504	$ 2,303,642	$ 2,390,884
Preferred stock of subsidiaries - not subject to mandatory redemption	34,293			34,293
Current liabilities
Short-term borrowings	0			172,568
Interest and dividends payable	57,901			21,333
Deferred credits and other liabilities
Deferred income taxes	258,942			262,462
Total liabilities and shareholders’ equity	16,991,818			16,284,244
Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	52,098			52,060
Plant and equipment	8,199,828			7,979,510
Financing lease right-of-use assets	124,372			48,371
Less accumulated depreciation	(3,222,030)			(3,086,499)
Construction in progress	357,289			275,353
Utility property, plant and equipment, net	5,511,557			5,268,795
Nonutility property, plant and equipment, less accumulated depreciation	6,942			6,945
Total property, plant and equipment, net	5,518,499			5,275,740
Investment in wholly owned subsidiaries, at equity	0			0
Current assets
Cash and cash equivalents	274,854			39,242	21,304
Restricted cash	2,000			0	0
Advances to affiliates				0
Customer accounts receivable, net	241,762			288,338
Accrued unbilled revenues, net	179,327			183,280
Other accounts receivable, net	89,823			13,567
Fuel oil stock, at average cost	152,768			191,530
Materials and supplies, at average cost	99,526			79,568
Prepayments and other	54,538			33,482
Regulatory assets	57,921			52,273
Total current assets	1,152,519			881,280
Other long-term assets
Operating lease right-of-use assets	76,061			89,318
Regulatory assets	173,276			190,240
Other	158,092			160,889
Total other long-term assets	407,429			440,447
Total assets	7,078,447			6,597,467
Capitalization
Common stock equity	2,383,023	$ 2,371,889	$ 2,358,884	2,344,170	2,307,992	$ 2,289,595	$ 2,276,884	2,261,899
Preferred stock of subsidiaries - not subject to mandatory redemption	34,293			34,293
Long-term debt, net	1,934,044			1,584,854
Total capitalization	4,351,360			3,963,317
Current liabilities
Current portion of operating lease liabilities	17,012			19,095
Current portion of long-term debt	99,996			99,962
Accounts payable	201,699			202,492
Interest and dividends payable	30,058			17,176
Taxes accrued, including revenue taxes	274,272			289,902
Regulatory liabilities	26,325			31,475
Other	163,307			85,596
Total current liabilities	812,669			833,665
Deferred credits and other liabilities
Operating lease liabilities	66,299			78,715
Finance lease liabilities	118,140			46,048
Deferred income taxes	385,675			384,430
Regulatory liabilities	1,075,449			1,024,175
Unamortized tax credits	89,747			95,300
Defined benefit pension liability	48,884			49,748
Other	130,224			122,069
Total deferred credits and other liabilities	1,914,418			1,800,485
Total liabilities and shareholders’ equity	7,078,447			6,597,467
Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings	0			87,967
Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings				0
Consolidating adjustments | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	0			0
Plant and equipment	0			0
Financing lease right-of-use assets	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	(703,311)			(701,833)
Current assets
Cash and cash equivalents	0			0	0
Restricted cash	0
Advances to affiliates				(26,200)
Customer accounts receivable, net	0			0
Accrued unbilled revenues, net	0			0
Other accounts receivable, net	(44,577)			(22,384)
Fuel oil stock, at average cost	0			0
Materials and supplies, at average cost	0			0
Prepayments and other	0			(1,041)
Regulatory assets	0			0
Total current assets	(44,577)			(49,625)
Other long-term assets
Operating lease right-of-use assets	0			0
Regulatory assets	0			0
Other	(16,988)			(16,288)
Total other long-term assets	(16,988)			(16,288)
Total assets	(764,876)			(767,746)
Capitalization
Common stock equity	(703,311)			(701,833)	(689,016)			(676,237)
Preferred stock of subsidiaries - not subject to mandatory redemption	0			0
Long-term debt, net	0			0
Total capitalization	(703,311)			(701,833)
Current liabilities
Current portion of operating lease liabilities	0			0
Current portion of long-term debt	0			0
Accounts payable	0			0
Interest and dividends payable	0			(80)
Taxes accrued, including revenue taxes	0			(1,041)
Regulatory liabilities	0			0
Other	(44,577)			(22,304)
Total current liabilities	(44,577)			(49,625)
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	(16,988)			(16,288)
Other	0			0
Total deferred credits and other liabilities	(16,988)			(16,288)
Total liabilities and shareholders’ equity	(764,876)			(767,746)
Consolidating adjustments | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings				0
Consolidating adjustments | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings				(26,200)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	42,859			42,860
Plant and equipment	5,422,393			5,260,685
Financing lease right-of-use assets	88,297			48,371
Less accumulated depreciation	(1,953,609)			(1,855,150)
Construction in progress	258,204			215,560
Utility property, plant and equipment, net	3,858,144			3,712,326
Nonutility property, plant and equipment, less accumulated depreciation	5,295			5,298
Total property, plant and equipment, net	3,863,439			3,717,624
Investment in wholly owned subsidiaries, at equity	703,311			701,833
Current assets
Cash and cash equivalents	233,518			27,579	13,295
Restricted cash	2,000
Advances to affiliates				0
Customer accounts receivable, net	172,730			216,802
Accrued unbilled revenues, net	132,552			136,508
Other accounts receivable, net	115,498			23,746
Fuel oil stock, at average cost	112,468			153,342
Materials and supplies, at average cost	58,834			48,130
Prepayments and other	41,304			24,040
Regulatory assets	49,489			46,504
Total current assets	918,393			676,651
Other long-term assets
Operating lease right-of-use assets	36,627			42,752
Regulatory assets	146,735			154,040
Other	112,601			115,028
Total other long-term assets	295,963			311,820
Total assets	5,781,106			5,407,928
Capitalization
Common stock equity	2,383,023			2,344,170	2,307,992			2,261,899
Preferred stock of subsidiaries - not subject to mandatory redemption	22,293			22,293
Long-term debt, net	1,426,353			1,126,915
Total capitalization	3,831,669			3,493,378
Current liabilities
Current portion of operating lease liabilities	7,308			9,775
Current portion of long-term debt	49,998			49,981
Accounts payable	141,738			143,253
Interest and dividends payable	21,304			12,398
Taxes accrued, including revenue taxes	196,037			207,798
Regulatory liabilities	9,999			13,145
Other	148,400			64,659
Total current liabilities	574,784			615,176
Deferred credits and other liabilities
Operating lease liabilities	35,967			41,049
Finance lease liabilities	82,935			46,048
Deferred income taxes	274,577			271,234
Regulatory liabilities	770,268			729,683
Unamortized tax credits	65,153			69,614
Defined benefit pension liability	65,872			65,907
Other	79,881			75,839
Total deferred credits and other liabilities	1,374,653			1,299,374
Total liabilities and shareholders’ equity	5,781,106			5,407,928
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings				87,967
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings				26,200
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	5,645			5,606
Plant and equipment	1,448,183			1,425,442
Financing lease right-of-use assets	36,075			0
Less accumulated depreciation	(663,303)			(644,457)
Construction in progress	35,281			23,989
Utility property, plant and equipment, net	861,881			810,580
Nonutility property, plant and equipment, less accumulated depreciation	115			115
Total property, plant and equipment, net	861,996			810,695
Investment in wholly owned subsidiaries, at equity	0			0
Current assets
Cash and cash equivalents	32,716			5,092	5,154
Restricted cash	0
Advances to affiliates				4,500
Customer accounts receivable, net	34,550			39,339
Accrued unbilled revenues, net	22,062			23,839
Other accounts receivable, net	7,124			5,519
Fuel oil stock, at average cost	14,400			16,964
Materials and supplies, at average cost	13,077			9,783
Prepayments and other	5,468			6,346
Regulatory assets	5,110			2,435
Total current assets	134,507			113,817
Other long-term assets
Operating lease right-of-use assets	29,193			34,283
Regulatory assets	14,583			21,816
Other	33,011			32,654
Total other long-term assets	76,787			88,753
Total assets	1,073,290			1,013,265
Capitalization
Common stock equity	352,170			344,720	338,598			332,900
Preferred stock of subsidiaries - not subject to mandatory redemption	7,000			7,000
Long-term debt, net	249,308			224,439
Total capitalization	608,478			576,159
Current liabilities
Current portion of operating lease liabilities	6,942			6,690
Current portion of long-term debt	19,999			19,992
Accounts payable	25,436			32,113
Interest and dividends payable	3,924			2,576
Taxes accrued, including revenue taxes	40,706			42,436
Regulatory liabilities	6,842			8,553
Other	23,182			20,856
Total current liabilities	127,031			133,216
Deferred credits and other liabilities
Operating lease liabilities	22,575			27,817
Finance lease liabilities	35,205			0
Deferred income taxes	50,405			50,615
Regulatory liabilities	197,045			194,222
Unamortized tax credits	12,410			13,150
Defined benefit pension liability	0			129
Other	20,141			17,957
Total deferred credits and other liabilities	337,781			303,890
Total liabilities and shareholders’ equity	1,073,290			1,013,265
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings				0
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings				0
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	3,594			3,594
Plant and equipment	1,329,252			1,293,383
Financing lease right-of-use assets	0			0
Less accumulated depreciation	(605,118)			(586,892)
Construction in progress	63,804			35,804
Utility property, plant and equipment, net	791,532			745,889
Nonutility property, plant and equipment, less accumulated depreciation	1,532			1,532
Total property, plant and equipment, net	793,064			747,421
Investment in wholly owned subsidiaries, at equity	0			0
Current assets
Cash and cash equivalents	8,543			6,494	2,778
Restricted cash	0
Advances to affiliates				21,700
Customer accounts receivable, net	34,482			32,197
Accrued unbilled revenues, net	24,713			22,933
Other accounts receivable, net	11,778			6,686
Fuel oil stock, at average cost	25,900			21,224
Materials and supplies, at average cost	27,615			21,655
Prepayments and other	7,766			4,137
Regulatory assets	3,322			3,334
Total current assets	144,119			140,360
Other long-term assets
Operating lease right-of-use assets	10,241			12,283
Regulatory assets	11,958			14,384
Other	29,468			29,495
Total other long-term assets	51,667			56,162
Total assets	988,850			943,943
Capitalization
Common stock equity	351,064			357,036	350,341			343,260
Preferred stock of subsidiaries - not subject to mandatory redemption	5,000			5,000
Long-term debt, net	258,383			233,500
Total capitalization	614,447			595,536
Current liabilities
Current portion of operating lease liabilities	2,762			2,630
Current portion of long-term debt	29,999			29,989
Accounts payable	34,525			27,126
Interest and dividends payable	4,830			2,282
Taxes accrued, including revenue taxes	37,529			40,709
Regulatory liabilities	9,484			9,777
Other	36,302			22,385
Total current liabilities	155,431			134,898
Deferred credits and other liabilities
Operating lease liabilities	7,757			9,849
Finance lease liabilities	0			0
Deferred income taxes	60,693			62,581
Regulatory liabilities	108,136			100,270
Unamortized tax credits	12,184			12,536
Defined benefit pension liability	0			0
Other	30,202			28,273
Total deferred credits and other liabilities	218,972			213,509
Total liabilities and shareholders’ equity	988,850			943,943
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings				0
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings				0
Other subsidiary | Reportable Legal Entities | Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	0			0
Plant and equipment	0			0
Financing lease right-of-use assets	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	77			77	77
Restricted cash	0
Advances to affiliates				0
Customer accounts receivable, net	0			0
Accrued unbilled revenues, net	0			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	77			77
Other long-term assets
Operating lease right-of-use assets	0			0
Regulatory assets	0			0
Other	0			0
Total other long-term assets	0			0
Total assets	77			77
Capitalization
Common stock equity	77			77	$ 77			$ 77
Preferred stock of subsidiaries - not subject to mandatory redemption	0			0
Long-term debt, net	0			0
Total capitalization	77			77
Current liabilities
Current portion of operating lease liabilities	0			0
Current portion of long-term debt	0			0
Accounts payable	0			0
Interest and dividends payable	0			0
Taxes accrued, including revenue taxes	0			0
Regulatory liabilities	0			0
Other	0			0
Total current liabilities	0			0
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
Other	0			0
Total deferred credits and other liabilities	0			0
Total liabilities and shareholders’ equity	$ 77			77
Other subsidiary | Reportable Legal Entities | Hawaiian Electric Consolidated | Nonrelated Party
Current liabilities
Short-term borrowings				0
Other subsidiary | Reportable Legal Entities | Hawaiian Electric Consolidated | Affiliated Entity
Current liabilities
Short-term borrowings				$ 0