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Collaborative Arrangements - Collaborative Arrangements Narrative (Details) shares in Millions, $ in Millions | 3 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Mar. 31, 2016 USD ($) shares | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Mar. 31, 2016 € / shares
Variable Interest Entity [Line Items] |  |  |  |  |
Available-for-sale Securities, Equity Securities, Noncurrent |  | $ 0 | $ 428 |  |
Collaboration Arrangement Investment in Counterparty Ownership Percentage | 14.75% |  |  |  |
Research and development expenses |  | $ 3,734 | $ 5,098 | $ 3,014 |
Percentage of Costs Responsible |  |  | 80.00% |  |
Janssen Pharmaceuticals [Member] |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Purchase price of goods less specified amount, maximum percentage |  |  | 30.00% |  |
Galapagos [Member] |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
License Fee Payment |  |  | $ 300 |  |
Available-for-sale Securities, Equity Securities, Noncurrent | $ 425 |  |  |  |
Share Price | € / shares |  |  |  |  | € 58
Investment Owned, Balance, Shares | shares | 6.8 |  |  |  |
Research and development expenses | $ 68 |  | $ 60 |  |
Percentage of Costs Responsible |  |  | 20.00% |  |
Galapagos [Member] | Minimum [Member] |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Potential Future Milestone Payment, Tiered Royalty Payment |  |  | 20.00% |  |
Galapagos [Member] | Maximum [Member] |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Potential Future Milestone Payment, Tiered Royalty Payment |  |  | 30.00% |  |
Development And Regulatory Milestones-Based [Member] | Galapagos [Member] |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Potential Future Milestone Payment |  |  | $ 755 |  |
Sales-Based Milestones [Member] | Galapagos [Member] |  |  |  |  |
Variable Interest Entity [Line Items] |  |  |  |  |
Potential Future Milestone Payment |  |  | $ 600 |  |

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- Definition Equity securities categorized neither as held-to-maturity nor trading which are intended be sold more than one year from the balance sheet date or operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26626-111562 + Details
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- Definition The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 730 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6420194&loc=d3e21568-108373 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 985 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6501960&loc=d3e128462-111756 + Details
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