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Derivative Financial Instruments And Hedging Activities (Details) - USD ($) $ in Millions | 6 Months Ended |  |  |
--- | --- | --- | --- | ---
Jun. 30, 2019 | Dec. 31, 2018 | Jul. 01, 2018 | Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Notional forward foreign exchange contracts outstanding | $ 4,800 | $ 5,800 |  |
Average maturity of foreign currency forward contracts, in years | 2 years |  |  |
Cash and equivalents | $ 702 | 963 | $ 1,862 | $ 2,983
Marketable securities held in trust | $ 194 | $ 202 |  |
Maximum |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Maturity of fixed-income securities, in years | 5 years |  |  |

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition Average period remaining before foreign currency exchange rate derivatives mature or expire, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3044-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118951113&loc=d3e6676-107765 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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