Financial Instruments, Hedging Activities and Fair Value Measurements (Cash Flow and Net Investment Hedges) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Derivatives, Fair Value [Line Items]
Ineffective portion of expense	$ 1
Interest Expense, Change In Fair Value Of Long Term Debt	5
Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) on Fair Value Hedges Recognized in Earnings	6
Fair Value Hedging [Member] \| Interest Rate Swap [Member] \| Interest Expense [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized Amount	1
Cash Flow Hedging [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Deferred in OCI	(6)	$ (15)
Gain (Loss) Recognized Amount	2	4
Cash Flow Hedging [Member] \| Foreign currency contracts [Member] \| Other Expense
Derivatives, Fair Value [Line Items]
Gain (Loss) Deferred in OCI	(6)	(15)
Gain (Loss) Recognized Amount	(3)	4
Net Investment Hedging [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Deferred in OCI	(94)	(42)
Gain (Loss) Recognized Amount	1
Net Investment Hedging [Member] \| Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Deferred in OCI	(26)	(4)
Gain (Loss) Recognized Amount	1
Net Investment Hedging [Member] \| Other Foreign Currency Denominated Debt [Member]
Derivatives, Fair Value [Line Items]
Gain (Loss) Deferred in OCI	(68)	$ (38)
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Accumulated Other Comprehensive Income, Deferred Gain(Loss) On Foreign Currency Forward Contracts	1
Not Designated as Hedging Instrument \| Foreign currency contracts [Member] \| Other Expense
Derivatives, Fair Value [Line Items]
Gain (Loss) Recognized Amount	$ 4

Accumulated Other Comprehensive Income, Deferred Gain(Loss) On Foreign Currency Forward Contracts

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- Definition

Interest Expense, Change In Fair Value Of Long Term Debt

+ References

No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

The portion of losses on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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