v3.25.1
FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Apr. 16, 2025
Dec. 31, 2024
Dec. 05, 2024
Fair Value of Financial Instruments [Line Items]          
Investments not required to be disclosed $ 374     $ 370  
Senior Notes | TrAIL | Subsequent Event | 5.00%, $600 Million Senior Notes          
Fair Value of Financial Instruments [Line Items]          
Face amount of debt     $ 600    
Issuance interest rate     5.00%    
Senior Notes | JERSEY CENTRAL POWER & LIGHT COMPANY | Unsecured Senior Notes Due 2035          
Fair Value of Financial Instruments [Line Items]          
Face amount of debt         $ 700
Corporate-Owned Life Insurance          
Fair Value of Financial Instruments [Line Items]          
Gain on investments $ 2 $ 9