Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Mar. 27, 2016	Sep. 27, 2015
Assets:
Total short-term investments	$ 123.2	$ 81.3
Available-for-sale securities	605.0	312.5
Total Assets	2,071.3	2,029.4
Liabilities:
Total Liabilities	61.5	33.7
Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	1,294.4	1,530.1
Short-term Investments [Member]
Assets:
Available-for-sale securities	54.3	15.5
Trading securities	68.9	65.8
Total short-term investments	123.2	81.3
Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	35.7	50.8
Long-term Investments [Member]
Assets:
Available-for-sale securities	605.0	312.5
Other Long-Term Assets [Member]
Assets:
Derivative assets	13.0	54.7
Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	28.8	19.2
Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	32.7	14.5
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total Assets	1,607.0	1,700.7
Liabilities:
Total Liabilities	4.4	3.6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	1,294.4	1,530.1
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	4.1	0.0
Trading securities	68.9	65.8
Total short-term investments	73.0	65.8
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	239.6	104.8
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	0.0	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	4.4	3.6
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	458.6	322.8
Liabilities:
Total Liabilities	57.1	30.1
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:
Available-for-sale securities	50.2	15.5
Trading securities	0.0	0.0
Total short-term investments	50.2	15.5
Significant Other Observable Inputs (Level 2) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	35.7	50.8
Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	359.7	201.8
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	13.0	54.7
Significant Other Observable Inputs (Level 2) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	24.4	15.6
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	32.7	14.5
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Total Assets	5.7	5.9
Liabilities:
Total Liabilities	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:
Available-for-sale securities	0.0	0.0
Trading securities	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:
Available-for-sale securities	5.7	5.9
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
Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	13.5	10.2
Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	230.8	121.8
Corporate Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Corporate Debt Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	13.5	10.2
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	230.8	121.8
Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Corporate Debt Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Equity Securities [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	29.2
Equity Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
Equity Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	29.2
Equity Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
Foreign Government Obligations [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	3.5	2.0
Foreign Government Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	25.9	18.5
Foreign Government Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Foreign Government Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Foreign Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	3.5	2.0
Foreign Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	25.9	18.5
Foreign Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Foreign Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
U.S. Government Treasury Securities [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	4.1
U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	239.6	104.8
U.S. Government Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	4.1
U.S. Government Treasury Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	239.6	104.8
U.S. Government Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
U.S. Government Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
U.S. Government Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
U.S. Government Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Agency Obligations [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	3.0
Agency Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	9.8	8.6
Agency Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
Agency Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Agency Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	3.0
Agency Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	9.8	8.6
Agency Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
Agency Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	5.7	5.9
Auction Rate Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Auction Rate Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Auction Rate Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	5.7	5.9
State and Local Government Obligations [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		3.3
State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	10.7	9.7
State and Local Government Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		0.0
State and Local Government Obligations [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
State and Local Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		3.3
State and Local Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	10.7	9.7
State and Local Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		0.0
State and Local Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Mortgage and Other Asset-backed Securities [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	1.0
Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	82.5	43.2
Mortgage and Other Asset-backed Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
Mortgage and Other Asset-backed Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Mortgage and Other Asset-backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	1.0
Mortgage and Other Asset-backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	82.5	43.2
Mortgage and Other Asset-backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0
Mortgage and Other Asset-backed Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	$ 0.0	$ 0.0