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Financial Instruments - Effect of Net Investment Hedges (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Foreign exchange contracts |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income | $ 26 | $ (10) | $ (18)
Foreign exchange contracts | Other (income) expense, net |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing | (19) | (31) | (11)
Euro-denominated notes |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Amount of Pretax (Gain) Loss Recognized in Other Comprehensive Income | 385 | (75) | (183)
Euro-denominated notes | Other (income) expense, net |  |  |
Derivative Instruments and Hedging Activities Disclosures [Line Items] |  |  |
Amount of Pretax (Gain) Loss Recognized in Other (income) expense, net for Amounts Excluded from Effectiveness Testing | $ 0 | $ 0 | $ 0

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- Definition Amount, before tax and reclassification, of gain (loss) from derivative designated and qualifying as net investment hedge. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4CCC -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL109998896-113959 + Details
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- Definition Amount, before tax, of reclassification from accumulated other comprehensive income (AOCI) for gain (loss) from derivative designated and qualifying as net investment hedge. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4CCC -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL109998896-113959 + Details
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