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Intangible Assets and Goodwill (Details 1) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2017 | Mar. 31, 2016 | Feb. 01, 2017
Goodwill [Line Items] |  |  |
Increase to goodwill | $ 254.7 |  |
Income tax benefit (expense) | 239.2 | $ 356.4 |
Summary of roll forward of the changes in goodwill |  |  |
Goodwill, beginning of period | 3,669.3 |  |
Other | 1.8 |  |
Goodwill, end of period | 3,611.7 |  |
TECFIDERA | Fumapharm AG |  |  |
Goodwill [Line Items] |  |  |
Increase to goodwill | 300.0 |  |
Income tax benefit (expense) | 45.3 |  |
Bioverativ |  |  |
Goodwill [Line Items] |  |  |
Elimination of goodwill allocated to our hemophilia business | $ (314.1) |  | $ (314.1)

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