Collaborative and Other Relationships - Summary of Activity Related To Denali Therapeutics (Details) - Research and development - Denali Therapeutics - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Collaborative arrangements and non-collaborative arrangement transactions
Expense incurred by the collaboration	$ 22.1	$ 23.2	$ 38.7	$ 38.1
Expense reflected within statements of income	$ 13.2	$ 13.2	$ 23.2	$ 22.1