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v3.3.1.900

Fair Value Measurements (Details Textual) - USD ($) $ in Millions | 1 Months Ended | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Feb. 28, 2015 | Dec. 31, 2015 | Sep. 30, 2014 | Mar. 31, 2012 | Sep. 30, 2011 | Dec. 31, 2010 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Feb. 12, 2015
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Contingent consideration obligations |  | $ 301.3 |  |  |  |  | $ 301.3 | $ 200.0 |  |
Fair value measurements, changes in valuation techniques |  |  |  |  |  |  | 0 | 0 |  |
(Gain) loss on fair value remeasurement of contingent consideration |  |  | $ 49.4 |  |  |  | $ (30.5) | $ 38.9 | $ 0.5 |
Additions |  |  |  |  |  |  | 274.5 | 0.0 |  |
Potential future milestone payments |  | 2,800.0 |  |  |  |  | 2,800.0 |  |  |
Maximum contingent consideration in the form of development and approval milestones |  | 1,300.0 |  |  |  |  | 1,300.0 |  |  |
Convergence Pharmaceuticals |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Additions | $ 274.5 |  |  |  |  |  |  |  |  |
Potential future milestone payments |  |  |  |  |  |  |  |  |  | $ 450.0
Contingent consideration obligations |  | $ 297.5 |  |  |  |  | 297.5 |  |  |
Discount rate used for net cash outflow projections for fair value measurement | 2.00% | 3.00% |  |  |  |  |  |  |  |
In-process research and development |  |  |  |  |  |  |  |  |  | $ 424.6
Stromedix, Inc. |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Additions |  |  |  | $ 122.2 |  |  |  |  |  |
Contingent consideration obligations |  | $ 131.5 |  |  |  |  | 131.5 | 130.5 |  |
Maximum contingent consideration in the form of development and approval milestones |  | 419.0 |  |  |  |  | $ 419.0 |  |  |
Discount rate used for net cash outflow projections for fair value measurement |  |  |  |  |  |  | 2.00% |  |  |
Biogen Dompe SRL and Biogen Dompe Switzerland GmbH |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Additions |  |  |  |  | $ 38.8 |  |  |  |  |
Contingent consideration obligations |  | 0.0 |  |  |  |  | $ 0.0 | 15.5 |  |
Milestone payments made during period |  |  |  |  |  |  | 14.5 |  |  |
Biogen Idec International Neuroscience GmbH |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Additions |  |  |  |  |  | $ 81.2 |  |  |  |
Contingent consideration obligations |  | 77.0 |  |  |  |  | 77.0 | 69.5 |  |
Maximum contingent consideration in the form of development and approval milestones |  | $ 365.0 |  |  |  |  | $ 365.0 |  |  |
Discount rate used for net cash outflow projections for fair value measurement |  |  |  |  |  |  | 3.00% |  |  |
6.875% Senior Notes due 2018 |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Interest rate on senior notes |  | 6.875% |  |  |  |  | 6.875% |  |  |
2.90% Senior Notes due 2020 |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Interest rate on senior notes |  | 2.90% |  |  |  |  | 2.90% |  |  |
3.625% Senior Notes due 2022 |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Interest rate on senior notes |  | 3.625% |  |  |  |  | 3.625% |  |  |
4.05% Senior Notes due 2025 |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Interest rate on senior notes |  | 4.05% |  |  |  |  | 4.05% |  |  |
5.20% Senior Notes due 2045 |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Interest rate on senior notes |  | 5.20% |  |  |  |  | 5.20% |  |  |
Other long-term liabilities |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Contingent consideration obligations |  | $ 301.3 |  |  |  |  | $ 301.3 | $ 200.0 |  |
Accrued expenses and other | Convergence Pharmaceuticals |  |  |  |  |  |  |  |  |  |
Business Acquisition, Contingent Consideration [Line Items] |  |  |  |  |  |  |  |  |  |
Contingent consideration obligations |  | $ 197.2 |  |  |  |  | $ 197.2 |  |  |

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