Employee Benefit Plans - Change in Postretirement Benefit Obligation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in Benefit Obligation
Benefit obligation at beginning of period	$ 33	$ 34	$ 30
Service cost	2	2	2
Interest cost	1	1	1
Actuarial (gain) loss	1	(2)	3
Benefits paid	(2)	(2)	(2)
Benefit obligation at end of period	35	33	34
Change in Plan Assets
Fair value of plan assets at end of period	0	0	0
Funded status at end of period	$ (35)	$ (33)	$ (34)