Intangible Assets - Schedule of Other Intangible Assets, Net (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Indefinite-Lived Intangible Assets [Line Items]
Intangible assets, gross (excluding goodwill)	$ 470.3	$ 849.3
Accumulated Amortization	(40.5)	(23.4)
Intangible assets, net (excluding goodwill), total	429.8	825.9
Marketed Products
Indefinite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross	238.0	238.0
Accumulated Amortization	(37.0)	(21.9)
Finite-lived intangible assets, net, total	$ 201.0	216.1
Assembled Workforce
Indefinite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	3 years
Finite-lived intangible assets, gross	$ 7.7	7.7
Accumulated Amortization	(3.5)	(1.5)
Finite-lived intangible assets, net, total	$ 4.2	6.2
Minimum | Marketed Products
Indefinite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	10 years
Maximum | Marketed Products
Indefinite-Lived Intangible Assets [Line Items]
Estimated Useful Lives	12 years
In-process research and development
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 224.6	$ 603.6