v3.26.1
FAIR VALUE MEASUREMENTS - Schedule of Long-term Debt Redemption and Issuance (Details) - USD ($)
$ in Millions
1 Months Ended 6 Months Ended
May 31, 2026
Apr. 30, 2026
Mar. 31, 2026
Jun. 30, 2026
Jun. 30, 2025
Debt Instrument [Line Items]          
Repayments of debt       $ 694 $ 2,155
Debt issuances       2,075 4,125
JCP&L          
Debt Instrument [Line Items]          
Debt issuances       $ 350 $ 0
5.15% Unsecured Senior Notes Maturity 2026 | Senior Unsecured | FE PA          
Debt Instrument [Line Items]          
Issuance interest rate       5.15%  
Repayments of debt     $ 300    
4.00% Unsecured Senior Notes Maturing 2026 | Senior Unsecured | ATSI          
Debt Instrument [Line Items]          
Issuance interest rate   4.00%      
Repayments of debt   $ 75      
Face amount of debt   $ 75      
4.00%, $294 Million Notes Maturity 2026 | Senior Unsecured Convertible Notes | FE          
Debt Instrument [Line Items]          
Issuance interest rate 4.00%        
Repayments of debt $ 294        
4.15% Unsecured Senior Notes Maturity 2028 | Senior Unsecured | FE PA          
Debt Instrument [Line Items]          
Issuance interest rate       4.15%  
Debt issuances     300    
4.55% Unsecured Senior Notes Maturing 2031 | Senior Unsecured | FE PA          
Debt Instrument [Line Items]          
Issuance interest rate       4.55%  
Debt issuances     $ 550    
5.02% Unsecured Senior Notes Maturing 2036 | Senior Unsecured | MAIT          
Debt Instrument [Line Items]          
Issuance interest rate   5.02%      
Debt issuances   $ 250      
5.19% Unsecured Senior Notes Maturing 2033 | Senior Unsecured | ATSI          
Debt Instrument [Line Items]          
Issuance interest rate   5.19%      
Debt issuances   $ 175      
4.60% Unsecured Senior Notes Maturing 2030 | Senior Unsecured | JCP&L          
Debt Instrument [Line Items]          
Issuance interest rate 4.60%        
Debt issuances $ 350        
4.45%, $300 Million Notes Maturity 2029 | FMB | MP          
Debt Instrument [Line Items]          
Issuance interest rate 4.45%        
Debt issuances $ 300