v3.26.3
Pension Plans and Other Post-Retirement Benefit Plans - Components of Net Periodic Benefit Cost for Pension Plans and Other Post-Retirement Benefit Plans (Detail) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Pension Plans [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 4 $ 5 $ 13 $ 15
Interest expense 37 43 114 129
Expected return on plan assets (45) (50) (139) (148)
Amortization of net actuarial gain 0   0  
Settlement loss 0 0 7 1
Net periodic benefit cost (4) (2) (5) (3)
Other Post-Retirement Benefit Plans [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 0 1 0 1
Interest expense 1 1 5 5
Expected return on plan assets 0 0 0 0
Amortization of net actuarial gain 0   (1)  
Settlement loss 0 0 0 0
Net periodic benefit cost $ 1 $ 2 $ 4 $ 6