Goodwill and Other Intangible Assets (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Indefinite-lived Intangible Assets [Line Items]      
Amortization of Intangible Assets $ 154.2 $ 131.9  
Finite-Lived Intangible Assets, Gross 7,761.7   5,833.6
Goodwill 3,946.9   1,758.1
Indefinite-Lived Intangible Assets, Gross 4,242.6   1,769.5
Finite-Lived Intangible Assets, Accumulated Amortization (3,109.7)   (2,960.8)
Finite-Lived Intangible Assets, Net 4,652.0   2,872.8
Human Pharmaceutical Products [Member]      
Indefinite-lived Intangible Assets [Line Items]      
Goodwill 1,359.1   1,359.4
Animal Health Products [Member]      
Indefinite-lived Intangible Assets [Line Items]      
Goodwill 2,587.8   398.7
In Process Research and Development [Member]      
Indefinite-lived Intangible Assets [Line Items]      
Indefinite-Lived Intangible Assets (Excluding Goodwill) 295.7   11.4
Developed Technology Rights [Member]      
Indefinite-lived Intangible Assets [Line Items]      
Finite-Lived Intangible Assets, Gross 7,614.3   5,684.3
Finite-Lived Intangible Assets, Accumulated Amortization (3,062.0)   (2,915.6)
Finite-Lived Intangible Assets, Net 4,552.3   2,768.7
Other Intangible Assets [Member]      
Indefinite-lived Intangible Assets [Line Items]      
Finite-Lived Intangible Assets, Gross 147.4   149.3
Finite-Lived Intangible Assets, Accumulated Amortization (47.7)   (45.2)
Finite-Lived Intangible Assets, Net $ 99.7   $ 104.1