Derivative Instruments - Fair Value of Derivative Contracts (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets	$ 300	$ 28
Derivative liabilities	82	29
Total fair value of derivative instruments	218	(1)
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Assets \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	87	16
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Assets \| Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	11	0
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Liabilities \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	18
Foreign Exchange Contract \| Not Designated as Hedging Instrument \| Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative assets	52	10
Foreign Exchange Contract \| Not Designated as Hedging Instrument \| Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	45	11
Warrant \| Designated as Hedging Instrument \| Other Assets \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	150	0
Interest Rate Contract \| Designated as Hedging Instrument \| Other Assets \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	0	2
Interest Rate Contract \| Designated as Hedging Instrument \| Other Liabilities \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 37	$ 0

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226000-175313

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=82924980&loc=SL51823488-111719

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=82924980&loc=SL51823488-111719

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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-Publisher FASB
-Name Accounting Standards Codification
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