Fair Value (Schedule Of Financial Instruments Measured At Fair Value On Recurring Basis) (Details) - Fair Value, Recurring [Member] - USD ($) $ in Millions	Apr. 02, 2021	Oct. 02, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents*	$ 1,059.9	$ 566.7
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	1,423.6	980.0
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents*	1,034.9	561.2
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	1,062.3	604.4
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents*	25.0	5.5
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	361.3	375.6
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents*	0.0	0.0
Assets, Fair Value Disclosure, Recurring (Deprecated 2018-01-31)	0.0	0.0
US Treasury and Government [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	105.0	134.4
US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	27.4	43.2
US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	77.6	91.2
US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0.0	0.0
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	254.0	276.8
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0.0	0.0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	254.0	276.8
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0.0	0.0
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	4.7	2.1
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	0.0	0.0
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	4.7	2.1
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities	$ 0.0	$ 0.0