Pension and Postretirement Benefit Plans - Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates (Details) - Other Postretirement Benefits Plan [Member] - Foreign Plan [Member] $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Effect on total of service and interest cost components one percentage point increase	$ 1
Effect on OPEB obligations one percentage point increase	8
Effect on total of service and interest cost components one percentage point decrease	(1)
Effect on OPEB obligations one percentage point decrease	$ (7)