v3.26.1
Postretirement Benefit Obligations - Schedule of Net Benefit Costs (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Postemployment Benefits [Abstract]    
Postretirement benefits service cost $ 1 $ 1
Postretirement benefit (gain) loss    
Interest cost 16 17
Expected return on plan assets (19) (19)
Amortization of:    
Postretirement prior service cost (credit) (1) (1)
Postretirement benefit (gain) loss, net (4) (3)
Net periodic defined benefit cost (credit) $ (3) $ (2)