Inventory (Tables)

12 Months Ended

Dec. 31, 2011

Inventory [Abstract]

Components of inventories

	As of December 31,
(In millions)	2011		2010
Raw materials	$	83.8	$	59.0
Work in process		169.4		142.2
Finished goods		73.6		87.9
Total inventory	$	326.8	$	289.1

Components of inventory by product

	As of December 31,
(In millions)	2011		2010
AVONEX	$	113.3	$	87.0
TYSABRI		114.7		117.0
Other		15.0		26.1
Total finished goods and work in process		243.0		230.1
Raw materials		83.8		59.0
Total inventory	$	326.8	$	289.1