Financial Instruments and Fair Value Measurements (Schedule of Fair Value of Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 25, 2020	Dec. 27, 2019
Assets:
Other Assets, Fair Value Disclosure	$ 28.0	$ 26.2
Assets, Fair Value Disclosure	59.8	56.8
Recurring
Assets:
Rabbi Trust Investments, Fair Value Disclosure	31.8	30.6
Liabilities:
Deferred Compensation Liability, Fair Value	33.2	39.2
Contingent consideration and acquired contingent liabilities	27.2	69.3
Settlement Warrants, Fair Value Disclosure	9.3	43.4
Total liabilities at fair value	69.7	151.9
Recurring | Level 1
Assets:
Rabbi Trust Investments, Fair Value Disclosure	22.5	21.0
Other Assets, Fair Value Disclosure	28.0	26.2
Assets, Fair Value Disclosure	50.5	47.2
Liabilities:
Deferred Compensation Liability, Fair Value	0.0	0.0
Contingent consideration and acquired contingent liabilities	0.0	0.0
Settlement Warrants, Fair Value Disclosure	0.0	0.0
Total liabilities at fair value	0.0	0.0
Recurring | Level 2
Assets:
Rabbi Trust Investments, Fair Value Disclosure	9.3	9.6
Other Assets, Fair Value Disclosure	0.0	0.0
Assets, Fair Value Disclosure	9.3	9.6
Liabilities:
Deferred Compensation Liability, Fair Value	33.2	39.2
Contingent consideration and acquired contingent liabilities	0.0	0.0
Settlement Warrants, Fair Value Disclosure	0.0	0.0
Total liabilities at fair value	33.2	39.2
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	27.2	69.3
Settlement Warrants, Fair Value Disclosure	9.3	43.4
Total liabilities at fair value	$ 36.5	$ 112.7