Derivative Instruments (Income Statement Location) (Details) - Foreign Exchange Contract - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Net currency exchange rate gains (losses)	$ 3	$ (1)	$ 1	$ (13)
Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Net currency exchange rate gains (losses)	2	1	4	(7)
Other income (expense), net
Derivative Instruments, Gain (Loss) [Line Items]
Net currency exchange rate gains (losses)	$ 1	$ (2)	$ (3)	$ (6)

Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
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-Section 50
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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