Consolidated Statements of Common Stockholders' Equity (FirstEnergy Corp.) - USD ($) $ in Millions	Total	Common Stock	OPIC	AOCI	Accumulated Deficit	Series A Convertible Preferred Stock Preferred Stock
Beginning Balance (in shares) at Dec. 31, 2018		512,000,000				700,000
Beginning Balance at Dec. 31, 2018	$ 6,814	$ 51	$ 11,530	$ 41	$ (4,879)	$ 71
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME	912				912
Other comprehensive loss, net of tax	(21)			(21)
Stock-based compensation	41		41
Cash dividends declared on common stock	(824)		(824)
Cash dividends declared on preferred stock	(3)		(3)
Stock Investment Plan and certain share-based benefit plans (in shares)		3,000,000
Stock Investment Plan and certain share-based benefit plans	56	$ 0	56
Conversion of Series A Convertible Stock (in shares)		26,000,000				(700,000)
Conversion of Series A Convertible Stock	0	$ 3	68			$ (71)
Ending Balance (in shares) at Dec. 31, 2019		541,000,000				0
Ending Balance at Dec. 31, 2019	6,975	$ 54	10,868	20	(3,967)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME	1,079				1,079
Other comprehensive loss, net of tax	(25)			(25)
Stock-based compensation	26		26
Cash dividends declared on common stock	(846)		(846)
Stock Investment Plan and certain share-based benefit plans (in shares)		2,000,000
Stock Investment Plan and certain share-based benefit plans	$ 28	$ 0	28
Ending Balance (in shares) at Dec. 31, 2020	543,117,533	543,000,000				0
Ending Balance at Dec. 31, 2020	$ 7,237	$ 54	10,076	(5)	(2,888)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
NET INCOME	1,283				1,283
Other comprehensive loss, net of tax	(10)			(10)
Stock-based compensation	26		26
Cash dividends declared on common stock	(859)		(859)
Stock issuance (Note 9) (in shares)		26,000,000
Common Stock issuance (Note 9)	974	$ 3	971
Share-based benefit plans (in shares)		1,000,000
Share-based benefit plans	$ 24		24
Ending Balance (in shares) at Dec. 31, 2021	570,261,104	570,000,000				0
Ending Balance at Dec. 31, 2021	$ 8,675	$ 57	$ 10,238	$ (15)	$ (1,605)	$ 0