Acquisitions and Other Transactions (Other Transactions) (Details) - USD ($) $ in Millions				3 Months Ended	9 Months Ended
	Feb. 28, 2018	Dec. 25, 2017	Oct. 03, 2017	Sep. 30, 2018	Sep. 30, 2018	Aug. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Payment for Contingent Consideration Liability, Financing Activities				$ 20.0
Contingent consideration				418.8	$ 418.8		$ 453.7
Apicore [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net			$ 174.9
Acquired intangible assets, weighted average useful life, in years			7 years
Contingent consideration			$ 4.0
TOBI [Member]
Business Acquisition [Line Items]
Cash consideration				463.0
Payments to Acquire Businesses, Gross				240.0
Business Acquisition, expected future payments, next twelve months						$ 130.0
Business Acquisition, expected future payment, year two				$ 93.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Financial Assets						574.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net						$ 91.0
Acquired intangible assets, weighted average useful life, in years				10 years
Product rights and licenses | Other Companies [Member]
Business Acquisition [Line Items]
Cash consideration		$ 90.0			220.0
Acquired intangible assets, weighted average useful life, in years		5 years
Payments To Acquire Collaborative Agreement					160.0
Revance [Member]
Business Acquisition [Line Items]
Payments To Acquire Collaborative Agreement	$ 25.0
Fujifilm Kyowa Kirin Biologics [Member]
Business Acquisition [Line Items]
Payments To Acquire Collaborative Agreement					$ 53.7
Maximum | Revance [Member]
Business Acquisition [Line Items]
Development Milestone Payments	100.0
Sales Milestone Payments	$ 225.0