Fair Value Measurements - Foreign Currency Forward Contracts (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2021	Dec. 31, 2020
Foreign currency forward contracts designated as hedges \| 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	16 months
Buy USD, Sell Euro \| Foreign currency forward contracts designated as hedges \| Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Notional amount	$ 860	$ 542
Fair value gain (loss)	(2)	(24)
Buy USD, Sell GBP \| Foreign currency forward contracts not designated as hedges
Derivatives, Fair Value [Line Items]
Notional amount	219	116
Fair value gain (loss)	$ 0	$ (2)

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=123594938&loc=d3e13433-108611

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

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- Definition

Period remaining until the derivative contract matures, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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