Condensed Consolidated Statements of Changes in Shareholders' Equity and Common Stock Equity (unaudited) - USD ($) $ in Thousands	Total	Impact of ASU No. 2016-13	As reported under ASU No. 2016-13	Hawaiian Electric Company, Inc. and Subsidiaries	Common stock	Common stock As reported under ASU No. 2016-13	Common stock Hawaiian Electric Company, Inc. and Subsidiaries	Premium on capital stock Hawaiian Electric Company, Inc. and Subsidiaries	Retained Earnings	Retained Earnings Impact of ASU No. 2016-13	Retained Earnings As reported under ASU No. 2016-13	Retained Earnings Hawaiian Electric Company, Inc. and Subsidiaries	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) As reported under ASU No. 2016-13	Accumulated other comprehensive income (loss) Hawaiian Electric Company, Inc. and Subsidiaries
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	$ 2,162,280			$ 1,957,641	$ 1,669,267		$ 111,696	$ 681,305	$ 543,623			$ 1,164,541	$ (50,610)		$ 99
Beginning Balance at Dec. 31, 2018	2,162,280			1,957,641	$ 1,669,267		$ 111,696	681,305	543,623			1,164,541	(50,610)		99
Beginning Balance (in shares) at Dec. 31, 2018					108,879,000		16,751,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	2,183,515			1,957,641	$ 1,670,433		$ 111,696	681,305	554,451			1,171,354	(41,369)		123
Net income for common stock	45,688			32,126					45,688			32,126
Other comprehensive income (loss), net of tax (benefits)	9,241			24									9,241		24
Share-based expenses and other, net (in shares)					58,000
Share-based expenses and other, net	1,166				$ 1,166
Common stock dividends	(34,860)			(25,313)					(34,860)			(25,313)
Ending Balance at Mar. 31, 2019	2,183,515			1,964,478	$ 1,670,433		$ 111,696	681,305	554,451			1,171,354	(41,369)		123
Ending Balance (in shares) at Mar. 31, 2019					108,937,000		16,751,000
Beginning Balance at Dec. 31, 2018	2,162,280			1,957,641	$ 1,669,267		$ 111,696	681,305	543,623			1,164,541	(50,610)		99
Beginning Balance (in shares) at Dec. 31, 2018					108,879,000		16,751,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	2,242,689			1,957,641	$ 1,676,411		$ 111,696	681,305	590,651			1,200,081	(24,373)		172
Net income for common stock	151,619			111,479
Other comprehensive income (loss), net of tax (benefits)	26,237			73									26,237
Common stock dividends				(75,939)
Ending Balance at Sep. 30, 2019	2,242,689			1,993,254	$ 1,676,411		$ 111,696	681,305	590,651			1,200,081	(24,373)		172
Ending Balance (in shares) at Sep. 30, 2019					108,973,000		16,751,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	2,183,515			1,964,478	$ 1,670,433		$ 111,696	681,305	554,451			1,171,354	(41,369)		123
Beginning Balance at Mar. 31, 2019	2,183,515			1,964,478	$ 1,670,433		$ 111,696	681,305	554,451			1,171,354	(41,369)		123
Beginning Balance (in shares) at Mar. 31, 2019					108,937,000		16,751,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	2,208,586			1,971,762	$ 1,674,153		$ 111,696	681,305	562,103			1,178,615	(27,670)		146
Net income for common stock	42,512			32,574					42,512			32,574
Other comprehensive income (loss), net of tax (benefits)	13,699			23									13,699		23
Share-based expenses and other, net (in shares)					35,000
Share-based expenses and other, net	3,720				$ 3,720
Common stock dividends	(34,860)			(25,313)					(34,860)			(25,313)
Ending Balance at Jun. 30, 2019	$ 2,208,586			1,971,762	$ 1,674,153		$ 111,696	681,305	562,103			1,178,615	(27,670)		146
Ending Balance (in shares) at Jun. 30, 2019					108,972,000		16,751,000
Increase (decrease) in stockholders' equity
Common stock dividends (in dollars per share)	$ 0.32
Impact of adoption of ASU No. 2016-13	$ 2,208,586			1,971,762	$ 1,674,153		$ 111,696	681,305	562,103			1,178,615	(27,670)		146
Impact of adoption of ASU No. 2016-13	2,242,689			1,993,254	$ 1,676,411		111,696	681,305	590,651			1,200,081	(24,373)		172
Net income for common stock	63,419			46,779					63,419			46,779
Other comprehensive income (loss), net of tax (benefits)	3,297			26									3,297		26
Share-based expenses and other, net (in shares)					1,000
Share-based expenses and other, net	2,258				$ 2,258
Common stock dividends	(34,871)			(25,313)					(34,871)			(25,313)
Ending Balance at Sep. 30, 2019	2,242,689			1,993,254	$ 1,676,411		$ 111,696	681,305	590,651			1,200,081	(24,373)		172
Ending Balance (in shares) at Sep. 30, 2019					108,973,000		16,751,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	2,242,689			1,993,254	$ 1,676,411		$ 111,696	681,305	590,651			1,200,081	(24,373)		172
Impact of adoption of ASU No. 2016-13	2,280,260	$ (15,372)	$ 2,264,888	2,047,352	1,678,257	$ 1,678,257	113,678	714,824	622,042	$ (15,372)	$ 606,670	1,220,129	(20,039)	$ (20,039)	(1,279)
Beginning Balance at Dec. 31, 2019	$ 2,280,260	(15,372)	2,264,888	2,047,352	$ 1,678,257	1,678,257	$ 113,678	714,824	622,042	(15,372)	606,670	1,220,129	(20,039)	(20,039)	(1,279)
Beginning Balance (in shares) at Dec. 31, 2019	108,973,328				108,973,000		17,048,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	$ 2,280,260	(15,372)	2,264,888	2,047,352	$ 1,678,257	1,678,257	$ 113,678	714,824	622,042	(15,372)	606,670	1,220,129	(20,039)	(20,039)	(1,279)
Ending Balance at Jan. 01, 2020	$ 2,280,260	(15,372)	2,264,888
Increase (decrease) in stockholders' equity
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning Balance at Dec. 31, 2019	$ 2,280,260	(15,372)	2,264,888	2,047,352	$ 1,678,257	1,678,257	$ 113,678	714,824	622,042	(15,372)	606,670	1,220,129	(20,039)	(20,039)	(1,279)
Beginning Balance (in shares) at Dec. 31, 2019	108,973,328				108,973,000		17,048,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	$ 2,280,260	(15,372)	2,276,505	2,044,499	$ 1,678,257	1,674,261	$ 113,678	714,824	622,042	(15,372)	604,071	1,217,250	(20,039)	(1,827)	(1,253)
Net income for common stock	33,420			23,905					33,420			23,905
Other comprehensive income (loss), net of tax (benefits)	18,212			26									18,212		26
Share-based expenses and other, net (in shares)					172,000
Share-based expenses and other, net	(3,996)				$ (3,996)
Common stock dividends	$ (36,019)			(26,784)					(36,019)			(26,784)
Ending Balance at Mar. 31, 2020			2,276,505	2,044,499		1,674,261	$ 113,678	714,824			604,071	1,217,250		(1,827)	(1,253)
Ending Balance (in shares) at Mar. 31, 2020					109,145,000		17,048,000
Increase (decrease) in stockholders' equity
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning Balance at Dec. 31, 2019	$ 2,280,260	(15,372)	2,264,888	2,047,352	$ 1,678,257	1,678,257	$ 113,678	714,824	622,042	(15,372)	606,670	1,220,129	(20,039)	(20,039)	(1,279)
Beginning Balance (in shares) at Dec. 31, 2019	108,973,328				108,973,000		17,048,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	$ 2,280,260	(15,372)	2,264,888	2,093,398	$ 1,678,007	1,678,257	$ 113,678	714,824	645,943	$ (15,372)	606,670	1,266,076	(20,039)	(20,039)	(1,180)
Net income for common stock	147,339			126,299
Other comprehensive income (loss), net of tax (benefits)	19,320			99									19,320
Common stock dividends				(80,352)
Ending Balance at Sep. 30, 2020	$ 2,323,231			2,093,398	$ 1,678,007		$ 113,678	714,824	645,943			1,266,076	(719)		(1,180)
Ending Balance (in shares) at Sep. 30, 2020	109,181,124				109,181,000		17,048,000
Increase (decrease) in stockholders' equity
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Impact of adoption of ASU No. 2016-13	$ 2,280,260	$ (15,372)	2,264,888
Impact of adoption of ASU No. 2016-13			2,276,505	2,044,499		1,674,261	$ 113,678	714,824			604,071	1,217,250		(1,827)	(1,253)
Beginning Balance at Mar. 31, 2020			2,276,505	2,044,499		1,674,261	$ 113,678	714,824			604,071	1,217,250		(1,827)	(1,253)
Beginning Balance (in shares) at Mar. 31, 2020					109,145,000		17,048,000
Increase (decrease) in stockholders' equity
Impact of adoption of ASU No. 2016-13	2,291,398		$ 2,276,505	2,060,069	$ 1,676,616	$ 1,674,261	$ 113,678	714,824	616,941		$ 604,071	1,232,795	(2,159)	$ (1,827)	(1,228)
Net income for common stock	48,887			42,329					48,887			42,329
Other comprehensive income (loss), net of tax (benefits)	(332)			25									(332)		25
Share-based expenses and other, net (in shares)					36,000
Share-based expenses and other, net	2,355				$ 2,355
Common stock dividends	(36,017)			(26,784)					(36,017)			(26,784)
Ending Balance at Jun. 30, 2020	$ 2,291,398			2,060,069	$ 1,676,616		$ 113,678	714,824	616,941			1,232,795	(2,159)		(1,228)
Ending Balance (in shares) at Jun. 30, 2020					109,181,000		17,048,000
Increase (decrease) in stockholders' equity
Common stock dividends (in dollars per share)	$ 0.33
Impact of adoption of ASU No. 2016-13	$ 2,291,398			2,060,069	$ 1,676,616		$ 113,678	714,824	616,941			1,232,795	(2,159)		(1,228)
Impact of adoption of ASU No. 2016-13	2,291,398			2,093,398	1,678,007		113,678	714,824	645,943			1,266,076	(719)		(1,180)
Net income for common stock	65,032			60,065					65,032			60,065
Other comprehensive income (loss), net of tax (benefits)	1,440			48									1,440		48
Share-based expenses and other, net	1,391				1,391
Common stock dividends	(36,030)			(26,784)					(36,030)			(26,784)
Ending Balance at Sep. 30, 2020	$ 2,323,231			2,093,398	$ 1,678,007		$ 113,678	714,824	645,943			1,266,076	(719)		(1,180)
Ending Balance (in shares) at Sep. 30, 2020	109,181,124				109,181,000		17,048,000
Increase (decrease) in stockholders' equity
Common stock dividends (in dollars per share)	$ 0.33
Impact of adoption of ASU No. 2016-13	$ 2,323,231			$ 2,093,398	$ 1,678,007		$ 113,678	$ 714,824	$ 645,943			$ 1,266,076	$ (719)		$ (1,180)