Employee Benefit Plans - Schedule of Changes in Benefit Obligation and Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in plan assets:
Fair value of plan assets as of January 1,	$ 98
Fair value of plan assets as of December 31,	89	$ 98
Defined Pension Benefits
Change in benefit obligation:
Defined benefit obligation	180	185	$ 204
Service cost	2	1	1
Interest cost	7	8	8
Benefits paid	(14)	(15)
Net actuarial loss (gain)	0	(13)
Change in plan assets:
Fair value of plan assets as of January 1,	222	239
Actual return on plan assets	17	(3)
Employer contributions	1	1
Benefits paid	(14)	(15)
Fair value of plan assets as of December 31,	226	222	239
Over (under) funded status as of December 31,	46	37
Other Postretirement Benefits
Change in benefit obligation:
Defined benefit obligation	39	45	55
Service cost	0	0	0
Interest cost	2	2	2
Benefits paid	(3)	(3)
Net actuarial loss (gain)	(5)	(9)
Change in plan assets:
Fair value of plan assets as of January 1,	5	7
Actual return on plan assets	1	(1)
Employer contributions	3	2
Benefits paid	(3)	(3)
Fair value of plan assets as of December 31,	6	5	$ 7
Over (under) funded status as of December 31,	$ (33)	$ (40)