Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued payroll and related costs	$ 344.4	$ 261.8
Accrued clinical expenses	142.7	142.2
Accrued sales-related charges, deductions, and royalties	249.0	182.7
Income taxes payable	49.4	20.8
Other accrued expenses and liabilities	301.3	164.6
Accrued expenses and other current liabilities	$ 1,086.8	$ 772.1