Collaborative and Other Relationships - Summary of Activity Related to ADUHELM Collaboration (Details) - ADUHELM - Eisai $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Research and development
Collaborative arrangements and non-collaborative arrangement transactions
Expense incurred by the collaboration	$ 149.4
Expense reflected within statements of income	82.2
Selling, general and administrative
Collaborative arrangements and non-collaborative arrangement transactions
Expense incurred by the collaboration	134.2
Expense reflected within statements of income	$ 71.5