Revenue (Summary of Revenue Recognized) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue	$ 6,805.6	$ 5,859.8
Net product revenue
Disaggregation of Revenue [Line Items]
Revenue	6,320.0	5,403.5
Collaboration and other revenue
Disaggregation of Revenue [Line Items]
Revenue	485.6	456.3
Collaboration and other revenue associated with prior period transfers of intellectual property
Disaggregation of Revenue [Line Items]
Revenue	$ 43.0	$ 35.4