Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ (983.8)		$ (941.1)
Interest cost capitalization related to large-scale biologic manufacturing facility	3.2	8.2
Hillerod, Denmark Facility [Member]
Property, Plant and Equipment [Line Items]
Average estimated useful life	20 years
Transfer from construction in progress	465.9
Cambridge Leases [Member]
Property, Plant and Equipment [Line Items]
Construction cost incurred not yet paid	112.8		86.5
Eisai [Member]
Property, Plant and Equipment [Line Items]
Term Of Lease	10 years
Cancellation Period of Lease	5 years
Minimum [Member] | Cambridge Leases [Member]
Property, Plant and Equipment [Line Items]
Expected charges to vacate building	15.0
Maximum [Member] | Cambridge Leases [Member]
Property, Plant and Equipment [Line Items]
Expected charges to vacate building	$ 30.0