Collaborative and Other Relationships - Acorda (Details) - Acorda - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Collaborative arrangements and non-collaborative arrangement transactions
Expected additional milestone payments when certain sales threshold is met	$ 15.0
Foreign sales required to trigger milestone	$ 100.0
Expense reflected within statements of income		$ 46.6	$ 44.5	$ 42.0