Intangible Assets (Summary of Intangible Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	$ 35,670.5	$ 37,923.3
Accumulated amortization	(5,560.0)	(4,877.2)
Intangible assets, net	30,110.5	33,046.1	$ 33,434.3	$ 34,697.5
Currently marketed products
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	29,731.9	31,973.5
Accumulated amortization	(5,167.8)	(4,549.2)
Intangible assets, net	24,564.1	27,424.3
IPR&D
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	5,112.9	5,113.9
Accumulated amortization	0.0	0.0
Intangible assets, net	5,112.9	5,113.9
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	825.7	835.9
Accumulated amortization	(392.2)	(328.0)
Intangible assets, net	$ 433.5	$ 507.9