Fair Value (Schedule Of Financial Instruments Measured At Fair Value On Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Mar. 30, 2018	Sep. 29, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 688.2	$ 592.6
Total	688.2	592.6
Contingent consideration liability recorded for business combinations	9.1	11.9
Total	9.1	11.9
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	688.2	592.6
Total	688.2	592.6
Contingent consideration liability recorded for business combinations	0.0	0.0
Total	0.0	0.0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0.0	0.0
Total	0.0	0.0
Contingent consideration liability recorded for business combinations	0.0	0.0
Total	0.0	0.0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0.0	0.0
Total	0.0	0.0
Contingent consideration liability recorded for business combinations	9.1	11.9
Total	$ 9.1	$ 11.9