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Segment Information (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net | $ 2,425.9 | $ 2,391.7 | $ 2,198.6 | $ 2,172.3 | $ 2,287.0 | $ 2,117.3 | $ 2,056.3 | $ 1,742.8 | $ 9,188.5 | $ 8,203.4 | $ 5,542.3
U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 6,545.8 | 5,566.7 | 3,581.0
Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 2,642.7 | 2,636.7 | 1,961.3
TECFIDERA |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 3,638.4 | 2,909.2 | 876.1
TECFIDERA | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 2,908.2 | 2,426.6 | 864.4
TECFIDERA | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 730.2 | 482.6 | 11.7
AVONEX |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 2,630.2 | 3,013.1 | 3,005.5
AVONEX | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 1,790.2 | 1,956.7 | 1,902.4
AVONEX | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 840.0 | 1,056.4 | 1,103.1
PLEGRIDY |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 338.5 | 44.5 | 0.0
PLEGRIDY | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 227.1 | 27.8 | 0.0
PLEGRIDY | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 111.4 | 16.7 | 0.0
TYSABRI |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 1,886.1 | 1,959.5 | 1,526.5
TYSABRI | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 1,103.1 | 1,025.1 | 814.2
TYSABRI | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 783.0 | 934.4 | 712.3
FAMPYRA |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 89.7 | 80.2 | 74.0
FAMPYRA | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0
FAMPYRA | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 89.7 | 80.2 | 74.0
ELOCTATE |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 319.7 | 58.4 | 0.0
ELOCTATE | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 308.3 | 58.4 | 0.0
ELOCTATE | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 11.4 | 0.0 | 0.0
ALPROLIX |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 234.5 | 76.0 | 0.0
ALPROLIX | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 208.9 | 72.1 | 0.0
ALPROLIX | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 25.6 | 3.9 | 0.0
FUMADERM |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 51.4 | 62.5 | 60.2
FUMADERM | U.S |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0
FUMADERM | Rest of world |  |  |  |  |  |  |  |  |  |  |
Revenue by product |  |  |  |  |  |  |  |  |  |  |
Product, net |  |  |  |  |  |  |  |  | $ 51.4 | $ 62.5 | $ 60.2

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