Short-Term Borrowings and Bank Lines of Credit (Details Textuals)			1 Months Ended	12 Months Ended
	Feb. 01, 2019 USD ($)	Oct. 19, 2018 USD ($) agreement	Jan. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Feb. 18, 2019 USD ($)	Jan. 31, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jan. 22, 2018 USD ($) agreement	Dec. 31, 2017 USD ($)
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Short-term borrowings				$ 1,250,000,000						$ 300,000,000
Average interest rate for borrowings				3.07%						3.24%
Minimum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Company contributions			$ 500,000,000		$ 382,000,000
Maximum | Affiliates
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility				364 days
Term Loan
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Number of agreements | agreement									2
Face amount of loan									$ 125,000,000
Outstanding borrowings		$ 1,750,000,000
Term Loan | Federal Funds Rate
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Spread on variable rate		0.50%
Term Loan | LIBOR
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Spread on variable rate		1.00%
Term Loan | $1.25B Term Loan
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Number of agreements | agreement		2
Term of revolving credit facility		364 days
Face amount of loan		$ 1,250,000,000
Term Loan | $500M Term Loan
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility		2 years
Face amount of loan		$ 500,000,000,000
FET | Minimum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Consolidated debt to total capitalization ratio (percent)				65.00%
FET | Maximum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Consolidated debt to total capitalization ratio (percent)				75.00%
Revolving Credit Facility | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Number of agreements | agreement		2
Revolving Credit Facility | Parent, the Utilities, FET and Certain Subsidiaries | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility		5 years
Revolving Credit Facility | FET | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility		$ 1,000,000,000
Line of Credit | Letter of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility				1 year
Line of Credit | Letter of Credit | FET
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility				$ 100,000,000
Line of Credit | Revolving Credit Facility
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility								$ 5,000,000,000
Available for Issuance of Letters of Credit | Minimum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Cross-default provision for other indebtedness				$ 100,000,000
Money Pool | Maximum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility				364 days
Money Pool | Regulated Companies
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Average interest rate for borrowings				2.26%
Money Pool | Unregulated Companies
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Average interest rate for borrowings				2.96%
FE | Revolving Credit Facility | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility		3,500,000,000
Available Liquidity		$ 2,500,000,000
FE | Line of Credit | Letter of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility				$ 250,000,000
Subsequent Event
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility						$ 3,500,000,000
Available Liquidity						3,490,000,000
Company contributions	$ 500,000,000
Subsequent Event | Line of Credit | FE and the Utilities
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Available Liquidity						10,000,000
Subsequent Event | Line of Credit | FET
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Available Liquidity						1,000,000,000
Subsequent Event | Line of Credit | Revolving Credit Facility
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility						3,500,000,000
Subsequent Event | Line of Credit | Revolving Credit Facility | FET
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility						1,000,000,000
Subsequent Event | FE | Revolving Credit Facility | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility							$ 2,500,000,000
Subsequent Event | FE | Revolving Credit Facility | FET | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility							$ 0
Subsequent Event | FE | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Available Liquidity						2,490,000,000
Subsequent Event | FE | Line of Credit | Revolving Credit Facility
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility						$ 2,500,000,000