Derivative Financial Instruments (Balance Sheet Location of Derivative Instruments) (Details) - Derivatives designated as hedging instruments - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Other current assets
Derivatives, Fair Value
Assets	$ 7	$ 3
Other Liabilities [Member]
Derivatives, Fair Value
Cash Flow Hedges	(5)	(1)
Other non-current liabilities
Derivatives, Fair Value
Net Investment Hedges	(88)	(64)
Long-term debt
Derivatives, Fair Value
Net Investment Hedges	$ 615	$ 592

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- Definition

Fair value as of the balance sheet date of all foreign currency derivative assets designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

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- Definition

Fair value as of the balance sheet date of all foreign currency derivatives designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(b),(c)(1)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

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- Definition

Fair value as of the balance sheet date of all foreign currency derivative liabilities designated as cash flow hedging instruments.

+ References

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