Financial Instruments and Fair Value Measurements - Schedule of Reconciliation of Changes in Fair Value of Contingent Liabilities (Details) - Recurring $ in Millions	9 Months Ended
	Sep. 26, 2025 USD ($)
Contingent Consideration [Roll Forward]
Beginning balance	$ 17.5
Ending balance	43.8
Level 3
Contingent Consideration [Roll Forward]
Beginning balance	17.5
Business Combination additions (Note 3)	25.2
Fair value adjustment	2.9
Payments	(1.8)
Ending balance	43.8
Level 3 | Terlivaz CVR
Contingent Consideration [Roll Forward]
Beginning balance	17.5
Business Combination additions (Note 3)	0.0
Fair value adjustment	2.5
Payments	0.0
Ending balance	20.0
Level 3 | Auxilium
Contingent Consideration [Roll Forward]
Beginning balance	0.0
Business Combination additions (Note 3)	24.8
Fair value adjustment	0.4
Payments	(1.7)
Ending balance	23.5
Level 3 | Other
Contingent Consideration [Roll Forward]
Beginning balance	0.0
Business Combination additions (Note 3)	0.4
Fair value adjustment	0.0
Payments	(0.1)
Ending balance	$ 0.3