v3.26.1
Employee Benefits - Schedule of Net Periodic Benefit (Income) Expense (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Components of net periodic (benefit) expense    
Recognition of prior service credit $ (6)  
Combined Pension Plan    
Components of net periodic (benefit) expense    
Service cost 4 $ 5
Interest cost 51 60
Expected return on plan assets (64) (63)
Settlement charges 9 0
Curtailment gain (loss) 5 0
Recognition of actuarial gain (loss) 28 35
Net periodic post-retirement benefit expense 33 37
Post-Retirement Benefit Plan    
Components of net periodic (benefit) expense    
Service cost 1 1
Interest cost 19 22
Curtailment gain (loss) (10) 0
Recognition of actuarial gain (loss) (7) (6)
Recognition of prior service credit (1) (2)
Net periodic post-retirement benefit expense $ 2 $ 15