Fair Value (Schedule Of Financial Instruments Measured At Fair Value On Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 29, 2017	Sep. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration liability recorded for business combinations	$ 10.7
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	592.6	$ 408.7
Auction rate security	0.0	2.3
Total	592.6	411.0
Contingent consideration liability recorded for business combinations	11.9	7.9
Total	11.9	7.9
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	592.6	408.7
Auction rate security	0.0	0.0
Total	592.6	408.7
Contingent consideration liability recorded for business combinations	0.0	0.0
Total	0.0	0.0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	0.0	0.0
Auction rate security	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, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market	0.0	0.0
Auction rate security	0.0	2.3
Total	0.0	2.3
Contingent consideration liability recorded for business combinations	11.9	7.9
Total	$ 11.9	$ 7.9