Intangible Assets and Goodwill - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Finite-Lived Intangible Assets, Net [Abstract]
Finite-Lived Intangible Assets, Gross	$ 14,078.8	$ 14,067.3
Accumulated Amortization	(6,824.3)	(6,687.8)
Net	7,254.5	7,379.5
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Cost	15,877.8	15,866.3
Accumulated Amortization	6,824.3	6,687.8
Net	$ 9,053.5	$ 9,178.5
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated life (in years)	1 year	1 year
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated life (in years)	30 years	30 years
In-process research and development
Indefinite-Lived Intangible Assets [Line Items]
Cost and net	$ 1,635.0	$ 1,635.0
Priority review voucher
Indefinite-Lived Intangible Assets [Line Items]
Cost and net	100.0	100.0
Trademarks and trade names
Indefinite-Lived Intangible Assets [Line Items]
Cost and net	$ 64.0	$ 64.0