Employee Benefit Plans - Pension (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
U.S. Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	$ 0	$ 0	$ 0	$ 0
Defined Benefit Plan, Interest Cost	15	18	30	36
Expected return on plan assets	(11)	(15)	(22)	(29)
Net benefit cost	4	3	8	7
Foreign Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	2	2	4	4
Defined Benefit Plan, Interest Cost	6	5	11	10
Expected return on plan assets	(8)	(8)	(16)	(17)
Net benefit cost	0	(1)	(1)	(3)
Pension Plan, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	2	2	4	4
Defined Benefit Plan, Interest Cost	21	23	41	46
Expected return on plan assets	(19)	(23)	(38)	(46)
Net benefit cost	$ 4	$ 2	$ 7	$ 4