Derivative and Other Financial Instruments - Notional Values of Outstanding Derivative Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Foreign exchange | Derivatives not designated as hedges
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 742	$ 575
Foreign exchange | Derivatives in cash flow hedges
Derivatives, Fair Value [Line Items]
Notional amount of derivative	694	864
Foreign exchange | Derivatives in fair value hedges
Derivatives, Fair Value [Line Items]
Notional amount of derivative	72	60
Commodities | Derivatives not designated as hedges
Derivatives, Fair Value [Line Items]
Notional amount of derivative	0	40
Commodities | Derivatives in cash flow hedges
Derivatives, Fair Value [Line Items]
Notional amount of derivative	$ 247	$ 276