Hedges and Derivative Financial Instruments - Schedule of Outstanding Derivative Contracts (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Fair value of hedged assets	$ 102	$ 142
Fair value of hedged liabilities	147	208
Derivative asset at fair value, current	72	89
Derivative asset at fair value, noncurrent	30	53
Total derivatives, hedge assets at fair value	102	142
Derivative liability at fair value, current	66	81
Derivative liability at fair value, noncurrent	81	127
Total derivatives, hedge liabilities at fair value	147	208
Derivatives accounted for as hedges
Derivatives, Fair Value [Line Items]
Fair value of hedged assets	69	84
Fair value of hedged liabilities	92	158
Derivatives accounted for as hedges \| Foreign exchange forwards/options
Derivatives, Fair Value [Line Items]
Notional Amount	3,135	3,113
Fair value of hedged assets	57	55
Fair value of hedged liabilities	$ 83	$ 157
Maximum term of foreign exchange forwards/options	50 months	56 months
Derivatives accounted for as hedges \| Commodity swaps/options
Derivatives, Fair Value [Line Items]
Notional Amount	$ 274	$ 269
Fair value of hedged assets	12	29
Fair value of hedged liabilities	$ 9	$ 1
Maximum term of commodity swaps/options	30 months	36 months
Derivatives not accounted for as hedges
Derivatives, Fair Value [Line Items]
Fair value of hedged assets	$ 33	$ 58
Fair value of hedged liabilities	55	50
Derivatives not accounted for as hedges \| Foreign exchange forwards/options
Derivatives, Fair Value [Line Items]
Notional Amount	3,810	3,390
Fair value of hedged assets	33	58
Fair value of hedged liabilities	$ 55	$ 50
Maximum term of foreign exchange forwards/options	27 months	33 months
Derivatives not accounted for as hedges \| Commodity swaps/options
Derivatives, Fair Value [Line Items]
Notional Amount	$ 1	$ 1
Fair value of hedged assets	0	0
Fair value of hedged liabilities	$ 0	$ 0
Maximum term of commodity swaps/options	0 months	5 months

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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