Employee Benefit Plans - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 1,058	$ 953	$ 1,086
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	128	(34)
Company contributions	23	24
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(76)	(86)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	29	(38)
Plan participant contributions	1	1
U.S. Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	1,377	1,269	1,444
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	212	(76)
Company contributions	0	0
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(104)	(99)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	0	0
Plan participant contributions	0	0
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	2,435	2,222	$ 2,530
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	340	(110)
Company contributions	23	24
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(180)	(185)
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	29	(38)
Plan participant contributions	$ 1	$ 1