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Financial Instruments - Information About Changes in Liabilities for Contingent Consideration (Details) $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2020 USD ($) | Mar. 31, 2019 USD ($) | Mar. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Fair value, beginning balance | $ 767 | $ 788 |  |
Changes in estimated fair value | 33 | (36) |  |
Payments | (106) | (85) |  |
Fair value, ending balance | 694 | 667 |  |
Current liability |  |  | $ 119 |
Contingent consideration | 694 | $ 667 | 694 | $ 767
Sanofi Pasteur |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Fair value, beginning balance | 625 |  |  |
Fair value, ending balance | 520 |  |  |
Contingent consideration | $ 625 |  | $ 520 | $ 625
Contingent consideration, measurement input, discount rate (as percent) |  |  |  | 0.115
Measurement Input, Discount Rate | Sanofi Pasteur |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Contingent consideration, measurement input, discount rate (as percent) |  |  |  | 0.08

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- Definition Amount of increase (decrease) in the value of a contingent consideration liability, including, but not limited to, differences arising upon settlement. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479 + Details
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- Definition Amount of liability recognized arising from contingent consideration in a business combination. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 35 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116859824&loc=d3e6819-128478 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 25 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476 + Details
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