Derivative Instruments - Fair Value of Derivative Contracts (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets	$ 350	$ 262
Derivative liabilities	43	48
Total fair value of derivative instruments	307	214
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Assets \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	45	72
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Assets \| Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	0	0
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Assets \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	6	4
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Liabilities \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	0	0
Foreign Exchange Contract \| Designated as Hedging Instrument \| Other Current Liabilities \| Net Investment Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	3	1
Foreign Exchange Contract \| Not Designated as Hedging Instrument \| Other Current Assets
Derivatives, Fair Value [Line Items]
Derivative assets	21	38
Foreign Exchange Contract \| Not Designated as Hedging Instrument \| Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liabilities	37	30
Warrant \| Designated as Hedging Instrument \| Other Assets \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	253	148
Interest Rate Contract \| Designated as Hedging Instrument \| Other Assets \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative assets	25	0
Interest Rate Contract \| Designated as Hedging Instrument \| Other Current Liabilities \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	1	7
Interest Rate Contract \| Designated as Hedging Instrument \| Other Liabilities \| Fair Value Hedging
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ 2	$ 10

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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