Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 26, 2016	Sep. 27, 2015
Assets:
Total short-term investments	$ 174.5	$ 81.3
Available-for-sale securities	819.5	312.5
Total Assets	3,173.5	2,029.4
Liabilities:
Total Liabilities	100.2	33.7
Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	2,141.8	1,530.1
Short-term Investments [Member]
Assets:
Available-for-sale securities	109.0	15.5
Trading securities	65.5	65.8
Total short-term investments	174.5	81.3
Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	27.4	50.8
Long-term Investments [Member]
Assets:
Available-for-sale securities	819.5	312.5
Other Long-Term Assets [Member]
Assets:
Derivative assets	10.3	54.7
Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	32.5	19.2
Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	67.7	14.5
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total Assets	2,570.6	1,700.7
Liabilities:
Total Liabilities	0.9	3.6
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	2,141.8	1,530.1
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	51.9	0.0
Trading securities	65.5	65.8
Total short-term investments	117.4	65.8
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	3.8	0.0
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	307.6	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	0.9	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	597.2	322.8
Liabilities:
Total Liabilities	99.3	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	57.1	15.5
Trading securities	0.0	0.0
Total short-term investments	57.1	15.5
Significant Other Observable Inputs (Level 2) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	23.6	50.8
Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	506.2	201.8
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	10.3	54.7
Significant Other Observable Inputs (Level 2) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	31.6	15.6
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	67.7	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	31.5	10.2
Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	312.4	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	31.5	10.2
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	312.4	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	19.9
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	19.9
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	5.0	2.0
Foreign Government Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	36.3	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	5.0	2.0
Foreign Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	36.3	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	51.9
U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	307.6	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	51.9
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	307.6	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	0.0
Agency Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	22.0	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	0.0
Agency Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	22.0	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	16.0	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	16.0	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	0.2
Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	119.5	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	0.2
Mortgage and Other Asset-backed Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	119.5	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