Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 28, 2015	Sep. 28, 2014
Assets:
Total short-term investments	$ 94.7	$ 135.4
Available-for-sale securities	390.1	318.4
Total Assets	2,716.4	2,208.9
Liabilities:
Total Liabilities	23.7
Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	2,080.5	1,708.4
Short-term Investments [Member]
Assets:
Available-for-sale securities	19.6	63.2
Trading securities	75.1	72.2
Total short-term investments	94.7	135.4
Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	46.7	28.7
Long-term Investments [Member]
Assets:
Available-for-sale securities	390.1	318.4
Other Long-Term Assets [Member]
Assets:
Derivative assets	104.4	18.0
Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	13.2	2.4
Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	10.5
Fair Value, Inputs, Level 1 [Member]
Assets:
Total Assets	2,272.8	1,887.2
Liabilities:
Total Liabilities	1.0
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	2,080.5	1,708.4
Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	10.9
Trading securities	75.1	72.2
Total short-term investments	75.1	83.1
Fair Value, Inputs, Level 1 [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	0.2	0.9
Fair Value, Inputs, Level 1 [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	116.7	94.8
Fair Value, Inputs, Level 1 [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	0.3	0.0
Fair Value, Inputs, Level 1 [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	1.0	0.4
Fair Value, Inputs, Level 1 [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	0.0
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total Assets	437.7	307.9
Liabilities:
Total Liabilities	22.7
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	19.6	52.3
Trading securities	0.0	0.0
Total short-term investments	19.6	52.3
Significant Other Observable Inputs (Level 2) [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets	46.5	27.8
Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	267.5	209.8
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets	104.1	18.0
Significant Other Observable Inputs (Level 2) [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities	12.2	2.0
Significant Other Observable Inputs (Level 2) [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities	10.5
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Total Assets	5.9	13.8
Liabilities:
Total Liabilities	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	5.9	13.8
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
Agency Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	16.2	8.9
Agency Obligations [Member] | Fair Value, Inputs, 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] | Long-term Investments [Member]
Assets:
Available-for-sale securities	16.2	8.9
Agency Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	15.0	4.9
Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	161.6	130.9
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Corporate Debt Securities [Member] | Fair Value, Inputs, 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	15.0	4.9
Corporate Debt Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	161.6	130.9
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
Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	5.9	13.8
Auction Rate Securities [Member] | Fair Value, Inputs, 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	5.9	13.8
Foreign Government Obligations [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	1.2	33.7
Foreign Government Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	21.9	17.4
Foreign Government Obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
Foreign Government Obligations [Member] | Fair Value, Inputs, 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	1.2	33.7
Foreign Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	21.9	17.4
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
US Government Treasury Securities [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		10.9
US Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	116.7	94.8
US Government Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		10.9
US Government Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	116.7	94.8
US Government Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		0.0
US Government Treasury Securities [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
US Government Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		0.0
US Government Treasury Securities [Member] | Significant Unobservable Inputs (Level 3) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
State and Local Government Obligations [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	3.4	12.7
State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	16.4	6.7
State and Local Government Obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	0.0
State and Local Government Obligations [Member] | Fair Value, Inputs, 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	3.4	12.7
State and Local Government Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Long-term Investments [Member]
Assets:
Available-for-sale securities	16.4	6.7
State and Local Government Obligations [Member] | Significant Unobservable Inputs (Level 3) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities	0.0	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
Certificates Of Deposit [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		1.0
Certificates Of Deposit [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		0.0
Certificates Of Deposit [Member] | Significant Other Observable Inputs (Level 2) [Member] | Short-term Investments [Member]
Assets:
Available-for-sale securities		1.0
Certificates Of Deposit [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] | Long-term Investments [Member]
Assets:
Available-for-sale securities	51.4	45.9
Mortgage and Other Asset-backed Securities [Member] | Fair Value, Inputs, 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] | Long-term Investments [Member]
Assets:
Available-for-sale securities	51.4	45.9
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