Financial Instruments and Fair Value Measurements (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 25, 2020	Dec. 27, 2019	Jul. 24, 2019	Aug. 31, 2014	Apr. 30, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted Cash and Investments, Current	$ 24.0	$ 20.2	$ 0.0
Restricted Cash and Investments, Noncurrent	36.2	36.2	31.7
Silence Therapeutics [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities, FV-NI				$ 5.0
Unrealized Gain (Loss) on Investments	$ (4.7)	(3.8)	(20.2)
Debentures | 8.00% debentures due March 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	8.00%
Debentures | 8.00% debentures due March 2023 | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	8.00%
Debentures | 9.50% debentures due May 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	9.50%
Debentures | 9.50% debentures due May 2022 | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	9.50%
Senior Notes | 4.75% senior notes due April 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	4.75%					4.75%
Senior Notes | 4.75% senior notes due April 2023 | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	4.75%
Senior Notes | Five Point Five Percent Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.50%
Senior Notes | 5.75% senior notes due August 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.75%				5.75%
Senior Notes | 5.75% senior notes due August 2022 | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.75%
Debentures | Five Point Five Percent Notes [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.50%
Debentures | Five Point Six Two Five Percent Note
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.625%
Debentures | Five Point Six Two Five Percent Note | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Stated interest rate	5.625%
Carrying Value | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash	$ 60.2	56.4
Carrying Value | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash surrender value of life insurance	51.3	52.3
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	27.3	34.7
Debt and equity securities held in rabbi trusts	38.7	33.0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	0.0	0.0
Debt and equity securities held in rabbi trusts	24.9	23.5
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	0.0	0.0
Debt and equity securities held in rabbi trusts	13.8	9.5
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	27.3	34.7
Debt and equity securities held in rabbi trusts	0.0	0.0
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3 | Stratatech [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Contingent Liability	27.3	19.1
Fair Value, Measurements, Recurring | MNK-6105 [Member] | Fair Value, Inputs, Level 3 | Ocera [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of contingent consideration upon acquisition	$ 0.0	15.6
Nuclear Imaging
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration received, equity certificates		$ 9.0	$ 9.0