Acquisitions (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	1 Months Ended	12 Months Ended												1 Months Ended
	Jul. 08, 2011	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Business Acquisition [Member]	Dec. 31, 2010 Business Acquisition [Member]	Jul. 08, 2011 Janssen Pharmaceutica NV (J&J) [Member]	Dec. 20, 2010 Avid Radiopharmaceuticals [Member]	Jul. 20, 2010 Alnara Pharmaceuticals [Member]	May 28, 2010 Animal Health Sligo [Member]	Dec. 31, 2011 Asset Acquiisition [Member]	Dec. 31, 2010 Asset Acquiisition [Member]	Dec. 31, 2009 Asset Acquiisition [Member]	Dec. 31, 2009 InCyte Corporation [Member]
Business Acquisition, Cost of Acquired Entity, Purchase Price, Total								$ 307.8	$ 346.1	$ 291.7	$ 148.4
Cash paid for acquisition									286.3	188.7
Business Acquisition, Contingent Consideration, Potential Cash Payment									550.0	200.0
Business Acquisition, Contingent Consideration, at Fair Value									59.8	103.0
Business Acquisition, Products or Other Assets Acquired	50
Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets								223.5			76.2
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable								30.9	334.0	264.0
Business Acquisition, Purchase Price Allocation, Goodwill									119.6	100.5
Business Acquisition, Purchase Price Allocation, Other Noncurrent Liabilities									116.9	92.4
Business Acquisition, Purchase Price Allocation, Net Tangible Assets								53.4	9.4	19.6	72.2
Acquired in-process research and development		50.0	388.0	50.0	90.0										90.0
Acquired Indefinite-lived Intangible Asset, Amount						$ 30.9	$ 598.0					$ 388.0	$ 50.0	$ 90.0