Intangible Assets (Summary of Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	$ 35,610.9	$ 37,923.3
Accumulated amortization	(5,985.5)	(4,877.2)
Intangible assets, net	29,625.4	33,046.1	$ 33,350.3	$ 34,697.5
Currently marketed products
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	33,767.4	31,973.5
Accumulated amortization	(5,561.2)	(4,549.2)
Intangible assets, net	28,206.2	27,424.3
IPR&D
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	1,012.7	5,113.9
Accumulated amortization	0.0	0.0
Intangible assets, net	1,012.7	5,113.9
Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Gross acquired intangible assets	830.8	835.9
Accumulated amortization	(424.3)	(328.0)
Intangible assets, net	$ 406.5	$ 507.9