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Other Consolidated Financial Statement - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025	Dec. 31, 2025
Collaborative arrangements and non-collaborative arrangement transactions
Net unrealized (gains) losses recognized on equity securities	$ (19.1)	$ 41.0
Prepaid Taxes	661.6		$ 693.6
Other liabilities, noncurrent	787.1		748.5
Accrued income taxes	174.2		$ 166.4
Sage and Denali
Collaborative arrangements and non-collaborative arrangement transactions
Net unrealized (gains) losses recognized on equity securities	$ 19.2
Sage and Sangamo
Collaborative arrangements and non-collaborative arrangement transactions
Net unrealized (gains) losses recognized on equity securities		48.5
Denali Therapeutics
Collaborative arrangements and non-collaborative arrangement transactions
Net unrealized (gains) losses recognized on equity securities		$ 15.7