v3.26.1
Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Detail) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Pension Benefits [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 1 $ 1 $ 3 $ 3
Interest cost [1] 24 25 47 50
Expected return on plan assets [1] (29) (31) (59) (62)
Recognized net actuarial loss [1] 11 9 22 18
Net periodic benefit cost 7 4 13 9
Other Postretirement Benefits [Member]        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 1 1 1 1
Interest cost [1] 5 6 10 11
Recognized net actuarial loss [1] 1 1 2 2
Amortization of prior service benefit [1] (3) (3) (5) (6)
Net periodic benefit cost $ 4 $ 5 $ 8 $ 8
[1] These amounts were reported in Other expenses (income), net on the accompanying Statement of Consolidated Operations (see Note O).