Derivative Instruments - Location and Fair Values of Cash Flow Hedges (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Cash Flow Hedging \| Foreign exchange forward contracts \| Designated as Hedging Instrument \| Prepaid and other current assets
Derivatives, Fair Value [Line Items]
Derivative, fair value	$ 4	$ 3

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=118260190&loc=d3e13433-108611

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant