Fair Value Measurements - Foreign Currency Forward Contracts (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Total net revenues	$ 8,086	$ 6,489	$ 7,500
Buy USD, Sell Euro \| Designated as Hedges \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	542	350
Fair value of foreign currency forward contracts	(24)	(2)
Foreign currency forward contracts \| Cash Flow Hedging \| Reclassification out of Accumulated Other Comprehensive Income
Derivatives, Fair Value [Line Items]
Total net revenues	$ (3)	39	$ 7
Foreign currency forward contracts \| Designated as Hedges \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Maximum length of time over which our foreign currency forward contracts mature	11 months
Buy USD, Sell GBP \| Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount of foreign currency derivatives	$ 116	25
Fair value of foreign currency forward contracts	$ (2)	$ (2)

Fair value of the assets less the liabilities of a derivative or group of derivatives.

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