Financial Instruments and Fair Value Measurements (Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 26, 2021	Dec. 25, 2020
Assets:
Other Assets, Fair Value Disclosure	$ 39.5	$ 31.1
Assets, Fair Value Disclosure	72.4	64.1
Liabilities:
Settlement Warrants, Fair Value Disclosure	0.0	0.0
Recurring
Assets:
Rabbi Trust Investments, Fair Value Disclosure	32.9	33.0
Liabilities:
Deferred Compensation Liability, Fair Value	32.1	38.0
Contingent consideration and acquired contingent liabilities	23.9	34.7
Total liabilities at fair value	56.0	72.7
Recurring | Level 1
Assets:
Rabbi Trust Investments, Fair Value Disclosure	23.1	23.5
Other Assets, Fair Value Disclosure	39.5	31.1
Assets, Fair Value Disclosure	62.6	54.6
Liabilities:
Deferred Compensation Liability, Fair Value	0.0	0.0
Contingent consideration and acquired contingent liabilities	0.0	0.0
Total liabilities at fair value	0.0	0.0
Recurring | Level 2
Assets:
Rabbi Trust Investments, Fair Value Disclosure	9.8	9.5
Other Assets, Fair Value Disclosure	0.0	0.0
Assets, Fair Value Disclosure	9.8	9.5
Liabilities:
Deferred Compensation Liability, Fair Value	32.1	38.0
Contingent consideration and acquired contingent liabilities	0.0	0.0
Total liabilities at fair value	32.1	38.0
Recurring | Level 3
Assets:
Rabbi Trust Investments, Fair Value Disclosure	0.0	0.0
Other Assets, Fair Value Disclosure	0.0	0.0
Assets, Fair Value Disclosure	0.0	0.0
Liabilities:
Deferred Compensation Liability, Fair Value	0.0	0.0
Contingent consideration and acquired contingent liabilities	23.9	34.7
Total liabilities at fair value	$ 23.9	$ 34.7