v3.26.1
Employee Benefits - Schedule of Net Periodic Benefit (Income) Expense (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Combined Pension Plan        
Components of net periodic (benefit) expense        
Service cost $ 5 $ 6 $ 9 $ 11
Interest cost 51 60 102 120
Expected return on plan assets (64) (64) (128) (127)
Settlement charges 0 0 9 0
Curtailment gain (loss) 0 0 5 0
Recognition of prior service credit 0 (1) 0 (1)
Recognition of actuarial gain (loss) 28 37 56 72
Net periodic post-retirement benefit expense 20 38 53 75
Post-Retirement Benefit Plan        
Components of net periodic (benefit) expense        
Service cost 0 1 1 2
Interest cost 18 22 37 44
Curtailment gain (loss) 0 0 (10) 0
Recognition of prior service credit (1) (1) (2) (3)
Recognition of actuarial gain (loss) (8) (7) (15) (13)
Net periodic post-retirement benefit expense $ 9 $ 15 $ 11 $ 30