Electric utility segment - Consolidating Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment	$ 256,069	$ 246,158	$ 238,114
Other amortization	38,772	32,544	52,664
Deferred income taxes	(32,502)	(5,398)	(1,706)
Allowance for equity funds used during construction	(10,574)	(9,534)	(8,768)
Other	(7,580)	(7,060)	1,366
Changes in assets and liabilities
Increase in fuel oil stock	(87,569)	(45,819)	34,202
Decrease in regulatory assets	34,600	(13,874)	1,007
Increase in regulatory liabilities	44,888	15,358	(16,562)
Change in prepaid and accrued income taxes, tax credits and revenue taxes	121,636	41,331	(35,610)
Decrease in defined benefit pension and other postretirement benefit plans liability	(5,191)	(6,660)	(2,029)
Net cash provided by operating activities	454,476	375,673	429,407
Cash flows from investing activities
Capital expenditures	(344,037)	(314,524)	(383,895)
Other	13,046	27	3,412
Net cash used in investing activities	(1,128,682)	(1,179,592)	(1,413,648)
Cash flows from financing activities
Common stock dividends	(153,229)	(148,643)	(144,096)
Proceeds from issuance of long-term debt	227,312	285,886	415,997
Repayment of long-term debt	(221,910)	(82,262)	(178,969)
Net increase (decrease) in other bank borrowings with original maturities of three months or less	606,815	(1,365)	(25,440)
Proceeds from issuance of short-term debt	35,000	0	165,000
Repayment of short-term debt	0	(65,000)	(150,000)
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	83,652	(10,493)	(71,219)
Payments of obligations under finance leases	(849)
Other	(2,398)	(3,080)	(3,203)
Net cash used in financing activities	567,671	756,402	1,115,535
Net increase (decrease) in cash and equivalents	(106,535)	(47,517)	131,294
Cash, cash equivalents and restricted cash, January 1	311,462	358,979	227,685
Cash, cash equivalents and restricted cash, December 31	204,927	311,462	358,979
Less: Restricted cash	(5,050)	(5,911)	(17,558)
Cash and cash equivalents	199,877	305,551	341,421
Hawaiian Electric (parent only)
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation of property, plant and equipment	399	414	485
Changes in assets and liabilities
Net cash provided by operating activities	167,150	154,151	134,363
Cash flows from investing activities
Capital expenditures	(224)	(10)	(20)
Other	1,662	180	2,435
Net cash used in investing activities	(50,331)	(76,062)	(17,530)
Cash flows from financing activities
Common stock dividends	(153,229)	(148,643)	(144,096)
Proceeds from issuance of long-term debt	160,000	150,000	50,000
Repayment of long-term debt	(150,000)	(50,000)	0
Proceeds from issuance of short-term debt	35,000	0	65,000
Repayment of short-term debt	0	(15,000)	(50,000)
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	(4,315)	(10,493)	(32,232)
Other	(978)	(1,767)	(459)
Net cash used in financing activities	(116,687)	(77,909)	(117,487)
Net increase (decrease) in cash and equivalents	132	180	(654)
Cash, cash equivalents and restricted cash, January 1	479	299	953
Cash, cash equivalents and restricted cash, December 31	611	479	299
Hawaiian Electric Company, Inc. and Subsidiaries
Cash flows from operating activities
Net income (loss)	190,924	179,637	171,335
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries	0	0	0
Common stock dividends received from subsidiaries	0	0	0
Depreciation of property, plant and equipment	235,424	229,469	222,733
Other amortization	25,320	21,737	33,746
Deferred income taxes	(41,415)	(3,829)	3,151
State refundable credit	(10,999)	(10,582)	(9,961)
Bad debt expense	6,027	2,183	2,115
Allowance for equity funds used during construction	(10,574)	(9,534)	(8,768)
Accrued environmental reserve	0	0	6,556
Bill credits	0	2,000	0
Other	(139)	1,350	2,610
Changes in assets and liabilities
Increase in accounts receivable	(91,742)	(50,090)	(7,286)
Decrease (increase) in accrued unbilled revenues	(54,023)	(27,464)	15,285
Increase in fuel oil stock	(87,452)	(45,840)	33,699
Increase in materials and supplies	(7,691)	(4,533)	(6,642)
Decrease in regulatory assets	34,600	(13,874)	1,007
Increase in regulatory liabilities	44,888	15,358	(16,562)
Increase in accounts payable	22,355	17,671	(33,129)
Change in prepaid and accrued income taxes, tax credits and revenue taxes	103,198	26,930	(37,180)
Decrease in defined benefit pension and other postretirement benefit plans liability	(4,828)	(5,154)	(4,306)
Change in other assets and liabilities	(25,943)	(52,302)	(31,852)
Net cash provided by operating activities	327,930	273,133	336,551
Cash flows from investing activities
Capital expenditures	(329,457)	(292,000)	(350,864)
Advances to affiliates	0	0	0
Other	5,372	6,035	6,070
Net cash used in investing activities	(324,085)	(285,965)	(344,794)
Cash flows from financing activities
Common stock dividends	(125,900)	(111,700)	(107,134)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(1,995)	(1,995)	(1,995)
Proceeds from issuance of common stock	13,101	54,400	34,000
Proceeds from issuance of long-term debt	60,000	115,000	255,000
Repayment of long-term debt	(52,000)	0	(109,000)
Net increase (decrease) in other bank borrowings with original maturities of three months or less		0	(38,987)
Proceeds from issuance of short-term debt	0	0	100,000
Repayment of short-term debt	0	(50,000)	(100,000)
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	87,967	0	(38,987)
Payments of obligations under finance leases	(670)	0	0
Other	(364)	(941)	(2,209)
Net cash used in financing activities	(19,861)	4,764	29,675
Net increase (decrease) in cash and equivalents	(16,016)	(8,068)	21,432
Cash, cash equivalents and restricted cash, January 1	55,258	63,326	41,894
Cash, cash equivalents and restricted cash, December 31	39,242	55,258	63,326
Less: Restricted cash	0	(3,089)	(15,966)
Cash and cash equivalents	39,242	52,169	47,360
Hawaiian Electric Company, Inc. and Subsidiaries | Reportable Legal Entities | Hawaiian Electric (parent only)
Cash flows from operating activities
Net income (loss)	190,009	178,722	170,420
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries	(47,493)	(45,353)	(47,504)
Common stock dividends received from subsidiaries	31,600	29,700	30,704
Depreciation of property, plant and equipment	158,725	155,607	151,387
Other amortization	16,708	16,688	24,511
Deferred income taxes	(33,648)	(3,191)	2,130
State refundable credit	(7,375)	(7,120)	(6,668)
Bad debt expense	4,175	1,159	1,042
Allowance for equity funds used during construction	(8,464)	(7,734)	(7,335)
Accrued environmental reserve			6,556
Bill credits		1,400
Other	(65)	366	1,201
Changes in assets and liabilities
Increase in accounts receivable	(74,067)	(41,727)	(8,093)
Decrease (increase) in accrued unbilled revenues	(43,972)	(18,345)	8,832
Increase in fuel oil stock	(82,158)	(32,407)	30,226
Increase in materials and supplies	(6,124)	(3,220)	(3,910)
Decrease in regulatory assets	28,076	(15,422)	8,526
Increase in regulatory liabilities	28,621	16,269	(5,490)
Increase in accounts payable	18,657	9,828	(26,093)
Change in prepaid and accrued income taxes, tax credits and revenue taxes	77,903	21,217	(25,757)
Decrease in defined benefit pension and other postretirement benefit plans liability	(3,545)	(3,480)	(3,092)
Change in other assets and liabilities	(17,884)	(36,733)	(21,124)
Net cash provided by operating activities	229,679	216,224	280,469
Cash flows from investing activities
Capital expenditures	(223,223)	(194,984)	(229,127)
Advances to affiliates	1,000	25,700	1,000
Other	(5,687)	(29,596)	(14,340)
Net cash used in investing activities	(227,910)	(198,880)	(242,467)
Cash flows from financing activities
Common stock dividends	(125,900)	(111,700)	(107,134)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(1,080)	(1,080)	(1,080)
Proceeds from issuance of common stock	13,101	54,400	34,000
Proceeds from issuance of long-term debt	40,000	60,000	205,000
Repayment of long-term debt	(40,000)		(95,000)
Net increase (decrease) in other bank borrowings with original maturities of three months or less		0	(46,987)
Proceeds from issuance of short-term debt			100,000
Repayment of short-term debt		(50,000)	(100,000)
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	114,167
Payments of obligations under finance leases	(670)
Other	(241)	(702)	(1,618)
Net cash used in financing activities	(623)	(49,082)	(12,819)
Net increase (decrease) in cash and equivalents	1,146	(31,738)	25,183
Cash, cash equivalents and restricted cash, January 1	26,433	58,171	32,988
Cash, cash equivalents and restricted cash, December 31	27,579	26,433	58,171
Less: Restricted cash	0	(3,089)	(15,966)
Cash and cash equivalents	27,579	23,344	42,205
Hawaiian Electric Company, Inc. and Subsidiaries | Reportable Legal Entities | Hawaii Electric Light
Cash flows from operating activities
Net income (loss)	22,350	21,714	28,027
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries	0	0	0
Common stock dividends received from subsidiaries	0	0	0
Depreciation of property, plant and equipment	41,404	40,201	39,041
Other amortization	4,996	3,532	5,090
Deferred income taxes	(4,040)	(1,955)	(463)
State refundable credit	(1,734)	(1,672)	(1,593)
Bad debt expense	1,073	509	620
Allowance for equity funds used during construction	(898)	(586)	(543)
Accrued environmental reserve			0
Bill credits		300
Other	(50)	(41)	1,322
Changes in assets and liabilities
Increase in accounts receivable	(11,644)	(6,832)	(3,349)
Decrease (increase) in accrued unbilled revenues	(4,289)	(5,816)	3,327
Increase in fuel oil stock	(4,150)	(4,343)	430
Increase in materials and supplies	(56)	169	(1,583)
Decrease in regulatory assets	1,546	24	(2,908)
Increase in regulatory liabilities	7,977	(1,031)	(4,489)
Increase in accounts payable	3,294	4,723	(1,819)
Change in prepaid and accrued income taxes, tax credits and revenue taxes	11,117	3,861	(5,483)
Decrease in defined benefit pension and other postretirement benefit plans liability	(626)	(950)	(643)
Change in other assets and liabilities	213	(5,833)	(8,864)
Net cash provided by operating activities	66,483	45,974	46,120
Cash flows from investing activities
Capital expenditures	(49,004)	(50,516)	(64,346)
Advances to affiliates	(4,500)	0	8,000
Other	760	1,072	1,032
Net cash used in investing activities	(52,744)	(49,444)	(55,314)
Cash flows from financing activities
Common stock dividends	(16,400)	(14,600)	(16,320)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(534)	(534)	(534)
Proceeds from issuance of common stock	6,023	8,803	7,500
Proceeds from issuance of long-term debt	10,000	30,000	10,000
Repayment of long-term debt	(12,000)		(14,000)
Net increase (decrease) in other bank borrowings with original maturities of three months or less		(17,800)	18,800
Proceeds from issuance of short-term debt			0
Repayment of short-term debt		0	0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	(1,000)
Payments of obligations under finance leases	0
Other	(62)	(119)	(214)
Net cash used in financing activities	(13,973)	5,750	5,232
Net increase (decrease) in cash and equivalents	(234)	2,280	(3,962)
Cash, cash equivalents and restricted cash, January 1	5,326	3,046	7,008
Cash, cash equivalents and restricted cash, December 31	5,092	5,326	3,046
Less: Restricted cash	0	0	0
Cash and cash equivalents	5,092	5,326	3,046
Hawaiian Electric Company, Inc. and Subsidiaries | Reportable Legal Entities | Maui Electric
Cash flows from operating activities
Net income (loss)	26,058	24,554	20,392
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries	0	0	0
Common stock dividends received from subsidiaries	0	0	0
Depreciation of property, plant and equipment	35,295	33,661	32,305
Other amortization	3,616	1,517	4,145
Deferred income taxes	(3,727)	1,317	1,484
State refundable credit	(1,890)	(1,790)	(1,700)
Bad debt expense	779	515	453
Allowance for equity funds used during construction	(1,212)	(1,214)	(890)
Accrued environmental reserve			0
Bill credits		300
Other	(24)	1,025	87
Changes in assets and liabilities
Increase in accounts receivable	(10,680)	(3,071)	(1,343)
Decrease (increase) in accrued unbilled revenues	(5,762)	(3,303)	3,126
Increase in fuel oil stock	(1,144)	(9,090)	3,043
Increase in materials and supplies	(1,511)	(1,482)	(1,149)
Decrease in regulatory assets	4,978	1,524	(4,611)
Increase in regulatory liabilities	8,290	120	(6,583)
Increase in accounts payable	404	3,120	(5,217)
Change in prepaid and accrued income taxes, tax credits and revenue taxes	14,178	1,938	(5,998)
Decrease in defined benefit pension and other postretirement benefit plans liability	(657)	(724)	(571)
Change in other assets and liabilities	(3,623)	(8,196)	3,635
Net cash provided by operating activities	63,368	40,721	40,608
Cash flows from investing activities
Capital expenditures	(57,230)	(46,500)	(57,391)
Advances to affiliates	(21,700)	0	0
Other	1,253	1,073	960
Net cash used in investing activities	(77,677)	(45,427)	(56,431)
Cash flows from financing activities
Common stock dividends	(15,200)	(15,100)	(14,384)
Preferred stock dividends of Hawaiian Electric and subsidiaries	(381)	(381)	(381)
Proceeds from issuance of common stock	3,023	24,597	11,000
Proceeds from issuance of long-term debt	10,000	25,000	40,000
Repayment of long-term debt	0		0
Net increase (decrease) in other bank borrowings with original maturities of three months or less		(7,900)	(19,800)
Proceeds from issuance of short-term debt			0
Repayment of short-term debt		0	0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	0
Payments of obligations under finance leases	0
Other	(61)	(120)	(377)
Net cash used in financing activities	(2,619)	26,096	16,058
Net increase (decrease) in cash and equivalents	(16,928)	21,390	235
Cash, cash equivalents and restricted cash, January 1	23,422	2,032	1,797
Cash, cash equivalents and restricted cash, December 31	6,494	23,422	2,032
Less: Restricted cash	0	0	0
Cash and cash equivalents	6,494	23,422	2,032
Hawaiian Electric Company, Inc. and Subsidiaries | Reportable Legal Entities | Other subsidiaries
Cash flows from operating activities
Net income (loss)	0	0	0
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries	0	0	0
Common stock dividends received from subsidiaries	0	0	0
Depreciation of property, plant and equipment	0	0	0
Other amortization	0	0	0
Deferred income taxes	0	0	0
State refundable credit	0	0	0
Bad debt expense		0	0
Allowance for equity funds used during construction	0	0	0
Accrued environmental reserve			0
Bill credits		0
Other	0	0	0
Changes in assets and liabilities
Increase in accounts receivable	0	0	0
Decrease (increase) in accrued unbilled revenues	0	0	0
Increase in fuel oil stock	0	0	0
Increase in materials and supplies	0	0	0
Decrease in regulatory assets	0	0	0
Increase in regulatory liabilities
Increase in accounts payable	0	0	0
Change in prepaid and accrued income taxes, tax credits and revenue taxes	0	0	0
Decrease in defined benefit pension and other postretirement benefit plans liability	0	0	0
Change in other assets and liabilities	0	0	0
Net cash provided by operating activities	0	0	0
Cash flows from investing activities
Capital expenditures	0	0	0
Advances to affiliates	0	0	0
Other	0		(24)
Net cash used in investing activities	0	0	(24)
Cash flows from financing activities
Common stock dividends	0	0	0
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0	0
Proceeds from issuance of common stock	0	0	0
Proceeds from issuance of long-term debt	0	0	0
Repayment of long-term debt	0		0
Net increase (decrease) in other bank borrowings with original maturities of three months or less		0	0
Proceeds from issuance of short-term debt			0
Repayment of short-term debt		0	0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	0
Payments of obligations under finance leases	0
Other	0	0	0
Net cash used in financing activities	0	0	0
Net increase (decrease) in cash and equivalents	0	0	(24)
Cash, cash equivalents and restricted cash, January 1	77	77	101
Cash, cash equivalents and restricted cash, December 31	77	77	77
Less: Restricted cash	0	0	0
Cash and cash equivalents	77	77	77
Hawaiian Electric Company, Inc. and Subsidiaries | Consolidating adjustments
Cash flows from operating activities
Net income (loss)	(47,493)	(45,353)	(47,504)
Adjustments to reconcile net income to net cash provided by operating activities
Equity in earnings of subsidiaries	47,493	45,353	47,504
Common stock dividends received from subsidiaries	(31,600)	(29,700)	(30,704)
Depreciation of property, plant and equipment	0	0	0
Other amortization	0	0	0
Deferred income taxes	0	0	0
State refundable credit	0	0	0
Bad debt expense		0	0
Allowance for equity funds used during construction	0	0	0
Accrued environmental reserve			0
Bill credits		0
Other	0	0	0
Changes in assets and liabilities
Increase in accounts receivable	4,649	1,540	5,499
Decrease (increase) in accrued unbilled revenues	0	0	0
Increase in fuel oil stock	0	0	0
Increase in materials and supplies	0	0	0
Decrease in regulatory assets	0	0	0
Increase in regulatory liabilities	0
Increase in accounts payable	0	0	0
Change in prepaid and accrued income taxes, tax credits and revenue taxes	0	(86)	58
Decrease in defined benefit pension and other postretirement benefit plans liability	0	0	0
Change in other assets and liabilities	(4,649)	(1,540)	(5,499)
Net cash provided by operating activities	(31,600)	(29,786)	(30,646)
Cash flows from investing activities
Capital expenditures	0	0	0
Advances to affiliates	25,200	(25,700)	(9,000)
Other	9,046	33,486	18,442
Net cash used in investing activities	34,246	7,786	9,442
Cash flows from financing activities
Common stock dividends	31,600	29,700	30,704
Preferred stock dividends of Hawaiian Electric and subsidiaries	0	0	0
Proceeds from issuance of common stock	(9,046)	(33,400)	(18,500)
Proceeds from issuance of long-term debt	0	0	0
Repayment of long-term debt	0		0
Net increase (decrease) in other bank borrowings with original maturities of three months or less		25,700	9,000
Proceeds from issuance of short-term debt			0
Repayment of short-term debt		0	0
Net increase (decrease) in short-term borrowings from non-affiliates and affiliate with original maturities of three months or less	(25,200)
Payments of obligations under finance leases	0
Other	0	0	0
Net cash used in financing activities	(2,646)	22,000	21,204
Net increase (decrease) in cash and equivalents	0	0	0
Cash, cash equivalents and restricted cash, January 1	0	0	0
Cash, cash equivalents and restricted cash, December 31	0	0	0
Less: Restricted cash	0	0	0
Cash and cash equivalents	$ 0	$ 0	$ 0