Derivatives - BS Location (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	$ 138	$ 78
Fair Value of Derivative Instruments, Liabilities	111	197
Derivatives designated as hedging instruments
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	117	48
Fair Value of Derivative Instruments, Liabilities	49	172
Derivatives designated as hedging instruments \| Foreign currency forward/option contracts \| Other current assets
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	51	7
Derivatives designated as hedging instruments \| Foreign currency forward/option contracts \| Other assets
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	41	20
Derivatives designated as hedging instruments \| Foreign currency forward/option contracts \| Other current liabilities
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Liabilities	22	109
Derivatives designated as hedging instruments \| Foreign currency forward/option contracts \| Other liabilities
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Liabilities	11	56
Derivatives designated as hedging instruments \| Foreign currency forward/option contracts \| Current balance sheet location
Location and Fair Value Amount of Derivative Instruments
Derivative Notional Amount	2,107	2,204
Derivatives designated as hedging instruments \| Foreign currency forward/option contracts \| Noncurrent balance sheet location
Location and Fair Value Amount of Derivative Instruments
Derivative Notional Amount	1,250	1,392
Derivatives designated as hedging instruments \| Interest rate swap contracts \| Other assets
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	25	21
Derivatives designated as hedging instruments \| Interest rate swap contracts \| Other current liabilities
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Liabilities	5	1
Derivatives designated as hedging instruments \| Interest rate swap contracts \| Other liabilities
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Liabilities	11	6
Derivatives designated as hedging instruments \| Interest rate swap contracts \| Current balance sheet location
Location and Fair Value Amount of Derivative Instruments
Derivative Notional Amount	600	450
Derivatives designated as hedging instruments \| Interest rate swap contracts \| Noncurrent balance sheet location
Location and Fair Value Amount of Derivative Instruments
Derivative Notional Amount	1,303	1,503
Derivatives not designated as hedging instruments
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	21	30
Fair Value of Derivative Instruments, Liabilities	62	25
Derivatives not designated as hedging instruments \| Foreign currency forward/option contracts \| Other current assets
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Assets	21	30
Derivatives not designated as hedging instruments \| Foreign currency forward/option contracts \| Other current liabilities
Location and Fair Value Amount of Derivative Instruments
Fair Value of Derivative Instruments, Liabilities	62	25
Derivatives not designated as hedging instruments \| Foreign currency forward/option contracts \| Current balance sheet location
Location and Fair Value Amount of Derivative Instruments
Derivative Notional Amount	$ 3,201	$ 4,974

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624163-113959

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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