Pension, Savings and Other Postretirement Benefit Plans - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 28	$ 29
Postretirement benefits expense (credit)	2	$ 3
Non-U.S.
Defined Benefit Plan Disclosure [Line Items]
Contributions to pension plans	10
Non-U.S. | Minimum
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to funded pension plans in current year	25
Non-U.S. | Maximum
Defined Benefit Plan Disclosure [Line Items]
Expected contribution to funded pension plans in current year	$ 50