Pension, Other Postretirement Benefits and Savings Plans - Funded Status Recognized in the Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Noncurrent liabilities	$ (1,515)	$ (1,460)
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	0	0
Current liabilities	(20)	(21)
Noncurrent liabilities	(262)	(269)
Net amount recognized	(282)	(290)
United States | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	0	0
Current liabilities	(16)	(12)
Noncurrent liabilities	(337)	(301)
Net amount recognized	(353)	(313)
Non-U.S. | Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	349	231
Current liabilities	(21)	(19)
Noncurrent liabilities	(631)	(568)
Net amount recognized	$ (303)	$ (356)