v3.26.3
Employee Benefits - Schedule of Net Periodic Benefit (Income) Expense (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Combined Pension Plan        
Components of net periodic (benefit) expense        
Service cost $ 4 $ 5 $ 13 $ 16
Interest cost 52 61 154 181
Expected return on plan assets (64) (64) (192) (191)
Settlement charges 0 0 9 0
Curtailment gain (loss) 0 0 5 0
Recognition of prior service credit (1) 0 (1) (1)
Recognition of actuarial gain (loss) 28 36 84 108
Net periodic expense 19 38 72 113
Post-Retirement Benefit Plan        
Components of net periodic (benefit) expense        
Service cost 0 0 1 2
Interest cost 19 22 56 66
Curtailment gain (loss) 0 0 (10) 0
Recognition of prior service credit (2) (3) (4) (6)
Recognition of actuarial gain (loss) (6) (6) (21) (19)
Net periodic expense $ 11 $ 13 $ 22 $ 43