Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Apr. 01, 2012	Oct. 02, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	$ 743.4	$ 855.0
Short-term investments: Trading securities	58.7	47.6
Total short-term investments	802.1	902.6
Long-term investments	145.9	107.0
Total	948.0	1,009.6
Derivatives	22.9	31.5
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	399.7	606.0
Short-term investments: Trading securities	58.7	47.6
Total short-term investments	458.4	653.6
Long-term investments	0	0
Total	458.4	653.6
Derivatives	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	343.7	249.0
Short-term investments: Trading securities	0	0
Total short-term investments	343.7	249.0
Long-term investments	117.6	79.0
Total	461.3	328.0
Derivatives	22.9	31.5
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Short-term investments: Trading securities	0	0
Total short-term investments	0	0
Long-term investments	28.3	28.0
Total	28.3	28.0
Derivatives	0	0
Agency Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	70.0	20.0
Long-term investments	14.0
Agency Obligations [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Long-term investments	0
Agency Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	70.0	20.0
Long-term investments	14.0
Agency Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Long-term investments	0
Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	137.9	87.0
Commercial Paper [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Commercial Paper [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	137.9	87.0
Commercial Paper [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	67.4	78.0
Long-term investments	72.0	67.0
Corporate Debt Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Long-term investments	0	0
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	67.4	78.0
Long-term investments	72.0	67.0
Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Long-term investments	0	0
Government Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	399.7	606.0
Government Treasury Securities [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	399.7	606.0
Government Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Government Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
State And Local Government Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	28.3	28.0
State And Local Government Obligations [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	0	0
State And Local Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	0	0
State And Local Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term investments	28.3	28.0
Certificates Of Deposit [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	68.4	64.0
Long-term investments	31.6	12.0
Certificates Of Deposit [Member] | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Long-term investments	0	0
Certificates Of Deposit [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	68.4	64.0
Long-term investments	31.6	12.0
Certificates Of Deposit [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments: Available-for-sale securities	0	0
Long-term investments	$ 0	$ 0