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Subsequent Events (Details)		12 Months Ended
	Oct. 06, 2020 USD ($)	Dec. 31, 2019 USD ($) agreement	Nov. 17, 2020 USD ($)	Oct. 29, 2020 director
Subsequent Event [Line Items]
Amount of code of conduct payment		$ 4,000,000
Revolving Credit Facility | Line of Credit
Subsequent Event [Line Items]
Number of agreements | agreement		2
Maximum amount borrowed under revolving credit facility		$ 3,500,000,000
Revolving Credit Facility | Line of Credit | FE
Subsequent Event [Line Items]
Maximum amount borrowed under revolving credit facility		2,500,000,000
Revolving Credit Facility | Line of Credit | FET Sub-limits
Subsequent Event [Line Items]
Maximum amount borrowed under revolving credit facility		$ 1,000,000,000.0
Revolving Credit Facility | Line of Credit | Parent, the Utilities, FET and Certain Subsidiaries [Member]
Subsequent Event [Line Items]
Term of revolving credit facility		5 years
Subsequent Event
Subsequent Event [Line Items]
Number of additional executives terminated | director				2
Subsequent Event | Revolving Credit Facility | Line of Credit | FE
Subsequent Event [Line Items]
Maximum amount borrowed under revolving credit facility			$ 1,500,000,000
Subsequent Event | Mitchell v. FirstEnergy Corp. | Minimum | Pending Litigation
Subsequent Event [Line Items]
Amount of damages sought	$ 875,000

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
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- Definition

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
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