Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 29, 2019	Sep. 29, 2019
Assets:
Total short-term investments	$ 68.4	$ 70.5
Total Assets	3,374.5	3,016.0
Liabilities:
Financial Liabilities Fair Value Disclosure	11.9	18.2
Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	3,040.5	2,686.6
Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	4.0	4.0
Equity Securities, FV-NI	64.4	66.5
Total short-term investments	68.4	70.5
Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	23.2	12.6
Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	199.8	220.0
Other Long-Term Assets [Member]
Assets:
Derivative assets	42.6	26.3
Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	3.4	5.7
Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	8.5	12.5
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total Assets	3,213.4	2,859.6
Liabilities:
Financial Liabilities Fair Value Disclosure	0.0	1.1
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	3,040.5	2,686.6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Equity Securities, FV-NI	64.4	66.5
Total short-term investments	64.4	66.5
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	9.8	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	98.6	106.5
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	0.1	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	0.0	1.1
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	0.0	0.0
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total Assets	155.3	150.6
Liabilities:
Financial Liabilities Fair Value Disclosure	11.9	17.1
Significant Other Observable Inputs (Level 2) [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	0.0	0.0
Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	4.0	4.0
Equity Securities, FV-NI	0.0	0.0
Total short-term investments	4.0	4.0
Significant Other Observable Inputs (Level 2) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	13.4	12.6
Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	95.4	107.7
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	42.5	26.3
Significant Other Observable Inputs (Level 2) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	3.4	4.6
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	8.5	12.5
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Total Assets	5.8	5.8
Liabilities:
Financial Liabilities Fair Value Disclosure	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Equity Securities, FV-NI	0.0	0.0
Total short-term investments	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	5.8	5.8
Significant Unobservable Inputs (Level 3) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	0.0	0.0
Significant Unobservable Inputs (Level 3) [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	0.0	0.0
Commercial Paper [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.5	0.5
Commercial Paper [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Commercial Paper [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.5	0.5
Commercial Paper [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	3.5	3.5
Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	91.1	101.2
Corporate Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Corporate Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	3.5	3.5
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	91.1	101.2
Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	98.6	106.5
U.S. Government Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	98.6	106.5
U.S. Government Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
U.S. Government Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	3.6	4.9
State and Local Government Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
State and Local Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	3.6	4.9
State and Local Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	5.8	5.8
Auction Rate Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Auction Rate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Auction Rate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	5.8	5.8
Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.7	1.6
Mortgage and Other Asset-backed Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Mortgage and Other Asset-backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.7	1.6
Mortgage and Other Asset-backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	$ 0.0	$ 0.0