Financial Instruments and Fair Value Measurements (Schedule of Reconciliation of Changes in Fair Value of Contingent Liabilities) (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 25, 2020	Dec. 27, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent Consideration, Liability, Current	$ 13.2
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent Consideration, Liability, Noncurrent	14.0
Level 3 \| Recurring \| Contingent Liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	69.3
Accretion expense	0.5
Fair value adjustment	2.4
Ending balance	27.2
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements	(45.0)
Questcor Pharmaceuticals, Inc. \| Level 3 \| Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of contingent liability	0.0	$ 24.5
StrataGraft [Member] \| Stratatech \| Level 3 \| Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of contingent liability	15.8	29.0
MNK-6105 [Member] \| Ocera [Member] \| Level 3 \| Recurring
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Contingent Consideration, Liability	$ 11.4	$ 15.8

Amount of liability recognized arising from contingent consideration in a business combination.

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