Employee Benefit Plans - Components of Net Periodic Benefit Cost (Benefit) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 1
Interest cost	(28)	(24)
Expected return on plan assets	(51)	(51)
Amortization of prior service credit	0	0
Amortization of actuarial loss	(15)	(17)
Net periodic cost (benefit)	(7)	(9)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0
Interest cost	(1)	(1)
Expected return on plan assets	0	(1)
Amortization of prior service credit	(2)	(2)
Amortization of actuarial loss	(2)	(2)
Net periodic cost (benefit)	$ 1	$ 0