Employee Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 3	$ 2	$ 3
Interest cost	4	4	4
Expected return on plan assets	(6)	(5)	(6)
Amortization of actuarial losses	2	1	1
Net periodic cost	$ 3	$ 2	$ 2