Employee Benefit Plans - Pension Plan (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
U.S. Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	17	15	33	30
Expected return on plan assets	(12)	(11)	(22)	(22)
Net periodic benefit cost (income)	5	4	11	8
International Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	1	2	3	4
Interest cost	5	6	10	11
Expected return on plan assets	(7)	(8)	(15)	(16)
Net periodic benefit cost (income)	(1)	0	(2)	(1)
Total Pension Benefits
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Net service cost	1	2	3	4
Interest cost	22	21	43	41
Expected return on plan assets	(19)	(19)	(37)	(38)
Net periodic benefit cost (income)	$ 4	$ 4	$ 9	$ 7