Electric utility segment - Condensed consolidating balance sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Utility property, plant and equipment
Total property, plant and equipment, net	$ 5,429,420		$ 5,392,068
Current assets
Cash and cash equivalents	159,672		305,551	$ 247,443
Restricted cash	5,386		5,911	10,618
Other long-term assets
Operating lease right-of-use assets	120,600		122,416
Total assets	16,001,743		15,822,637
Capitalization
Common stock equity	2,233,504	$ 2,303,642	2,390,884	2,367,329	$ 2,321,293	$ 2,337,502
Preferred stock of subsidiaries - not subject to mandatory redemption	34,293		34,293
Current liabilities
Interest and preferred dividends payable	20,661		19,889
Deferred credits and other liabilities
Deferred income taxes	302,346		384,760
Total liabilities and shareholders’ equity	16,001,743		15,822,637
Hawaiian Electric Consolidated
Utility property, plant and equipment
Land	52,060		51,937
Plant and equipment	7,840,615		7,735,983
Less accumulated depreciation	(3,026,295)		(2,940,517)
Construction in progress	226,679		204,569
Utility property, plant and equipment, net	5,093,059		5,051,972
Nonutility property, plant and equipment, less accumulated depreciation	6,947		6,949
Total property, plant and equipment, net	5,100,006		5,058,921
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	15,503		52,169	23,666
Restricted cash	1,129		3,089	8,968
Advances to affiliates	0		0
Customer accounts receivable, net	247,270		186,859
Accrued unbilled revenues, net	178,876		129,155
Other accounts receivable, net	10,388		7,267
Fuel oil stock, at average cost	223,787		104,078
Materials and supplies, at average cost	74,581		71,877
Prepayments and other	36,540		46,031
Regulatory assets	73,578		66,664
Total current assets	861,652		667,189
Other long-term assets
Operating lease right-of-use assets	99,690		101,470
Regulatory assets	457,322		498,879
Other	168,326		165,166
Total other long-term assets	725,338		765,515
Total assets	6,686,996		6,491,625
Capitalization
Common stock equity	2,289,595	$ 2,276,884	2,261,899	2,171,396	$ 2,157,385	2,141,918
Preferred stock of subsidiaries - not subject to mandatory redemption	34,293		34,293
Long-term debt, net	1,684,520		1,624,427
Total capitalization	4,008,408		3,920,619
Current liabilities
Current portion of operating lease liabilities	27,976		49,368
Current portion of long-term debt	51,988		51,975
Short-term borrowings from non-affiliates	54,987		0
Short-term borrowings from affiliate	0		0
Accounts payable	199,156		160,007
Interest and preferred dividends payable	17,796		17,325
Taxes accrued, including revenue taxes	211,999		208,280
Regulatory liabilities	22,633		29,760
Other	80,624		71,569
Total current liabilities	667,159		588,284
Deferred credits and other liabilities
Operating lease liabilities	86,111		65,780
Deferred income taxes	400,110		408,634
Regulatory liabilities	985,442		967,008
Unamortized tax credits	100,112		103,945
Defined benefit pension and other postretirement benefit plans liability	315,475		321,780
Other	124,179		115,575
Total deferred credits and other liabilities	2,011,429		1,982,722
Total liabilities and shareholders’ equity	6,686,996		6,491,625
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric
Utility property, plant and equipment
Land	42,860		42,737
Plant and equipment	5,178,903		5,097,033
Less accumulated depreciation	(1,816,724)		(1,757,096)
Construction in progress	173,970		159,854
Utility property, plant and equipment, net	3,579,009		3,542,528
Nonutility property, plant and equipment, less accumulated depreciation	5,300		5,302
Total property, plant and equipment, net	3,584,309		3,547,830
Investment in wholly owned subsidiaries, at equity	686,338		676,237
Current assets
Cash and cash equivalents	6,578		23,344	17,367
Restricted cash	1,129		3,089	8,968
Advances to affiliates	3,000		1,000
Customer accounts receivable, net	176,838		135,949
Accrued unbilled revenues, net	128,083		92,469
Other accounts receivable, net	20,525		18,624
Fuel oil stock, at average cost	178,911		71,184
Materials and supplies, at average cost	43,836		42,006
Prepayments and other	27,424		32,140
Regulatory assets	64,999		58,695
Total current assets	651,323		478,500
Other long-term assets
Operating lease right-of-use assets	49,326		78,710
Regulatory assets	309,077		337,903
Other	129,402		130,546
Total other long-term assets	487,805		547,159
Total assets	5,409,775		5,249,726
Capitalization
Common stock equity	2,289,595		2,261,899	2,171,396		2,141,918
Preferred stock of subsidiaries - not subject to mandatory redemption	22,293		22,293
Long-term debt, net	1,176,691		1,136,620
Total capitalization	3,488,579		3,420,812
Current liabilities
Current portion of operating lease liabilities	18,985		45,955
Current portion of long-term debt	39,991		39,981
Short-term borrowings from non-affiliates	54,987
Short-term borrowings from affiliate	10,000		0
Accounts payable	156,222		111,024
Interest and preferred dividends payable	12,779		12,442
Taxes accrued, including revenue taxes	145,594		143,723
Regulatory liabilities	14,614		22,240
Other	61,438		56,752
Total current liabilities	514,610		432,117
Deferred credits and other liabilities
Operating lease liabilities	44,498		46,426
Deferred income taxes	285,438		291,027
Regulatory liabilities	709,954		695,152
Unamortized tax credits	73,441		76,201
Defined benefit pension and other postretirement benefit plans liability	216,789		220,480
Other	76,466		67,511
Total deferred credits and other liabilities	1,406,586		1,396,797
Total liabilities and shareholders’ equity	5,409,775		5,249,726
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Utility property, plant and equipment
Land	5,606		5,606
Plant and equipment	1,399,002		1,390,361
Less accumulated depreciation	(633,559)		(619,991)
Construction in progress	20,725		17,129
Utility property, plant and equipment, net	791,774		793,105
Nonutility property, plant and equipment, less accumulated depreciation	115		115
Total property, plant and equipment, net	791,889		793,220
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	5,754		5,326	3,754
Restricted cash	0		0	0
Advances to affiliates	0		0
Customer accounts receivable, net	37,631		28,469
Accrued unbilled revenues, net	26,245		19,529
Other accounts receivable, net	3,063		3,347
Fuel oil stock, at average cost	17,254		12,814
Materials and supplies, at average cost	10,001		9,727
Prepayments and other	4,911		6,052
Regulatory assets	4,452		3,051
Total current assets	109,311		88,315
Other long-term assets
Operating lease right-of-use assets	36,743		22,442
Regulatory assets	76,660		81,645
Other	19,163		17,124
Total other long-term assets	132,566		121,211
Total assets	1,033,766		1,002,746
Capitalization
Common stock equity	337,737		332,900	322,451		317,451
Preferred stock of subsidiaries - not subject to mandatory redemption	7,000		7,000
Long-term debt, net	244,393		234,390
Total capitalization	589,130		574,290
Current liabilities
Current portion of operating lease liabilities	6,441		3,378
Current portion of long-term debt	11,997		11,994
Short-term borrowings from non-affiliates	0
Short-term borrowings from affiliate	3,000		1,000
Accounts payable	22,524		26,139
Interest and preferred dividends payable	2,677		2,617
Taxes accrued, including revenue taxes	34,157		33,153
Regulatory liabilities	3,532		3,247
Other	17,749		14,158
Total current liabilities	102,077		95,686
Deferred credits and other liabilities
Operating lease liabilities	30,428		19,063
Deferred income taxes	51,403		53,298
Regulatory liabilities	182,303		179,267
Unamortized tax credits	13,643		14,212
Defined benefit pension and other postretirement benefit plans liability	47,783		48,900
Other	16,999		18,030
Total deferred credits and other liabilities	342,559		332,770
Total liabilities and shareholders’ equity	1,033,766		1,002,746
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Utility property, plant and equipment
Land	3,594		3,594
Plant and equipment	1,262,710		1,248,589
Less accumulated depreciation	(576,012)		(563,430)
Construction in progress	31,984		27,586
Utility property, plant and equipment, net	722,276		716,339
Nonutility property, plant and equipment, less accumulated depreciation	1,532		1,532
Total property, plant and equipment, net	723,808		717,871
Investment in wholly owned subsidiaries, at equity	0		0
Current assets
Cash and cash equivalents	3,094		23,422	2,468
Restricted cash	0		0	0
Advances to affiliates	10,000		0
Customer accounts receivable, net	32,801		22,441
Accrued unbilled revenues, net	24,548		17,157
Other accounts receivable, net	3,320		3,031
Fuel oil stock, at average cost	27,622		20,080
Materials and supplies, at average cost	20,744		20,144
Prepayments and other	3,593		7,114
Regulatory assets	4,127		4,918
Total current assets	129,849		118,307
Other long-term assets
Operating lease right-of-use assets	13,621		318
Regulatory assets	71,585		79,331
Other	20,280		18,510
Total other long-term assets	105,486		98,159
Total assets	959,143		934,337
Capitalization
Common stock equity	348,524		343,260	312,768		309,363
Preferred stock of subsidiaries - not subject to mandatory redemption	5,000		5,000
Long-term debt, net	263,436		253,417
Total capitalization	616,960		601,677
Current liabilities
Current portion of operating lease liabilities	2,550		35
Current portion of long-term debt	0		0
Short-term borrowings from non-affiliates	0
Short-term borrowings from affiliate	0		0
Accounts payable	20,410		22,844
Interest and preferred dividends payable	2,350		2,269
Taxes accrued, including revenue taxes	31,636		30,679
Regulatory liabilities	4,487		4,273
Other	18,105		18,540
Total current liabilities	79,538		78,640
Deferred credits and other liabilities
Operating lease liabilities	11,185		291
Deferred income taxes	63,269		64,309
Regulatory liabilities	93,185		92,589
Unamortized tax credits	13,028		13,532
Defined benefit pension and other postretirement benefit plans liability	51,264		53,257
Other	30,714		30,042
Total deferred credits and other liabilities	262,645		254,020
Total liabilities and shareholders’ equity	959,143		934,337
Hawaiian Electric Consolidated | Reportable Legal Entities | Other subsidiaries
Utility property, plant and equipment
Land	0		0
Plant and equipment	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		0	0
Advances to affiliates	0		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
Short-term borrowings from non-affiliates	0
Short-term borrowings from affiliate	0		0
Accounts payable	0		0
Interest and preferred 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
Deferred income taxes	0		0
Regulatory liabilities	0		0
Unamortized tax credits	0		0
Defined benefit pension and other postretirement benefit plans liability	0		0
Other	0		0
Total deferred credits and other liabilities	0		0
Total liabilities and shareholders’ equity	77		77
Hawaiian Electric Consolidated | Consolidating adjustments
Utility property, plant and equipment
Land	0		0
Plant and equipment	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	(686,338)		(676,237)
Current assets
Cash and cash equivalents	0		0	0
Restricted cash	0		0	0
Advances to affiliates	(13,000)		(1,000)
Customer accounts receivable, net	0		0
Accrued unbilled revenues, net	0		0
Other accounts receivable, net	(16,520)		(17,735)
Fuel oil stock, at average cost	0		0
Materials and supplies, at average cost	0		0
Prepayments and other	612		725
Regulatory assets	0		0
Total current assets	(28,908)		(18,010)
Other long-term assets
Operating lease right-of-use assets	0		0
Regulatory assets	0		0
Other	(519)		(1,014)
Total other long-term assets	(519)		(1,014)
Total assets	(715,765)		(695,261)
Capitalization
Common stock equity	(686,338)		(676,237)	$ (635,296)		$ (626,891)
Preferred stock of subsidiaries - not subject to mandatory redemption	0		0
Long-term debt, net	0		0
Total capitalization	(686,338)		(676,237)
Current liabilities
Current portion of operating lease liabilities	0		0
Current portion of long-term debt	0		0
Short-term borrowings from non-affiliates	0
Short-term borrowings from affiliate	(13,000)		(1,000)
Accounts payable	0		0
Interest and preferred dividends payable	(10)		(3)
Taxes accrued, including revenue taxes	612		725
Regulatory liabilities	0		0
Other	(16,668)		(17,881)
Total current liabilities	(29,066)		(18,159)
Deferred credits and other liabilities
Operating lease liabilities	0		0
Deferred income taxes	0		0
Regulatory liabilities	0		0
Unamortized tax credits	0		0
Defined benefit pension and other postretirement benefit plans liability	(361)		(857)
Other	0		(8)
Total deferred credits and other liabilities	(361)		(865)
Total liabilities and shareholders’ equity	$ (715,765)		$ (695,261)