Employee Benefit Plans - Pension (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
U.S. Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	$ 0	$ 0
Interest cost	15	18
Expected return on plan assets	(11)	(14)
Net benefit cost	4	4
Foreign Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	2	2
Interest cost	5	5
Expected return on plan assets	(8)	(9)
Net benefit cost	(1)	(2)
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	2	2
Interest cost	20	23
Expected return on plan assets	(19)	(23)
Net benefit cost	$ 3	$ 2