v3.20.1
Pension and Other Postretirement Benefits - Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Service cost $ 6  
Net periodic benefit cost 26  
Pension benefits    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Service cost 5 $ 0
Interest cost 26 1
Expected return on plan assets (40) (1)
Recognized net actuarial loss 30 1
Net periodic benefit cost 21 1
Other postretirement benefits    
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]    
Service cost 1 0
Interest cost 4 0
Recognized net actuarial loss 2 0
Amortization of prior service benefit (1) 0
Net periodic benefit cost $ 6 $ 0