Share-based Payments - Narrative (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
	Jul. 02, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based payment arrangement, expense		$ 28.8	$ 69.8	$ 91.0	$ 124.5
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based payment arrangement, expense		49.6	61.3	149.6	150.9
Human Immunology Biosciences
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based payment arrangement, expense	$ 56.4	0.0	$ 56.4	0.0	$ 56.4
Human Immunology Biosciences \| Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based payment arrangement, expense		42.5		42.5
Human Immunology Biosciences \| Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based payment arrangement, expense		$ 13.9		$ 13.9