v3.26.1
Pension and Other Postretirement Benefits (OPEB) - Schedule of Components of Net Periodic Benefit Cost (Credits) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Pension Benefits [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Service Cost (included in O&M Expense) $ 22 $ 22
Interest Cost 54 58
Expected Return on Plan Assets (82) (77)
Amortization of Net Prior Service Costs 0 0
Amortization of Net Actuarial Loss (Gain) 14 15
Non-Service Components of Pension and OPEB (Credits) Costs (14) (4)
Total Net Periodic Benefit Costs (Credits) 8 18
OPEB [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Service Cost (included in O&M Expense) 0 0
Interest Cost 8 9
Expected Return on Plan Assets (9) (8)
Amortization of Net Prior Service Costs 0 1
Amortization of Net Actuarial Loss (Gain) (1) (1)
Non-Service Components of Pension and OPEB (Credits) Costs (2) 1
Total Net Periodic Benefit Costs (Credits) $ (2) $ 1