Employee Benefit Plans - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	$ 1
Defined Benefit Plan Estimated Total Employer Contributions in Current Fiscal Year	2
Defined Benefit Plan, Plan Assets, Contributions by Employer	1
Postemployment Retirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	52
Defined Benefit Plan Estimated Total Employer Contributions in Current Fiscal Year	60
Defined Benefit Plan, Plan Assets, Contributions by Employer	8
Foreign Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	24
Defined Benefit Plan Estimated Total Employer Contributions in Current Fiscal Year	30
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 6