Derivative Instruments - Fair Value of Derivative Contracts (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative assets	$ 363	$ 28
Derivative liabilities	55	29
Total fair value of derivative instruments	308	(1)
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Assets \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	62	16
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Assets \| Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	9	0
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Assets \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	2	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 \| Designated as Hedging Instrument \| Other Current Liabilities \| Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	2	0
Foreign Exchange Contract \| Not Designated as Hedging Instrument \| Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative assets	14	10
Foreign Exchange Contract \| Not Designated as Hedging Instrument \| Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	12	11
Warrant \| Designated as Hedging Instrument \| Other Assets \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	276
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 Current Liabilities \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	9	0
Interest Rate Contract \| Designated as Hedging Instrument \| Other Liabilities \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 32	$ 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.

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