SHORT-TERM BORROWINGS AND BANK LINES OF CREDIT - Narrative (Details)		12 Months Ended
	Oct. 18, 2021 USD ($) agreement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Short-term borrowings		$ 100,000,000	$ 0
Average interest rate for borrowings		3.93%	2.42%
Revolving Credit Facility | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Number of agreements | agreement	6
Maximum amount borrowed under revolving credit facility	$ 4,500,000,000
Revolving Credit Facility | Parent, FET, the Utilities and the Transmission Companies | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility	5 years
Revolving Credit Facility | Parent, FET, the Utilities and the Transmission Companies | Line of Credit | Maximum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility			364 days
Revolving Credit Facility | Parent and FET | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility	$ 1,000,000,000.0
Revolving Credit Facility | Ohio Companies | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility	800,000,000
Revolving Credit Facility | Pennsylvania Companies | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility	950,000,000
Revolving Credit Facility | JCP&L | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility	500,000,000
Revolving Credit Facility | MP and PE | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility	400,000,000
Revolving Credit Facility | Transmission companies | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Maximum amount borrowed under revolving credit facility	$ 850,000,000
Revolving Credit Facility | FET, the Utilities and the Transmission Companies | Line of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Coverage ratio			250.00%
Revolving Credit Facility | FET, the Utilities and the Transmission Companies | Line of Credit | Minimum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Consolidated debt to total capitalization ratio (percent)			65.00%
Revolving Credit Facility | FET, the Utilities and the Transmission Companies | Line of Credit | Maximum
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Consolidated debt to total capitalization ratio (percent)			75.00%
Line of Credit | Letter of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Term of revolving credit facility		1 year
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		2.27%	1.01%
Money Pool | Unregulated Companies
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Average interest rate for borrowings		2.14%	0.60%
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
FE | Line of Credit | Letter of Credit
Short-Term Borrowings and Bank Lines of Credit (Textuals) [Abstract]
Outstanding borrowings		$ 4,000,000