Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 28, 2020	Sep. 29, 2019
Assets:
Total short-term investments	$ 229.9	$ 70.5
Total Assets	4,537.8	3,016.0
Liabilities:
Financial Liabilities Fair Value Disclosure	101.3	18.2
Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	3,965.9	2,686.6
Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	170.1	4.0
Equity Securities, FV-NI	59.8	66.5
Total short-term investments	229.9	70.5
Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets, current	20.7	12.6
Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	223.4	220.0
Other Long-Term Assets [Member]
Assets:
Derivative assets, Noncurrent	97.9	26.3
Accrued Liabilities [Member]
Liabilities:
Derivative liabilities, Current	21.3	5.7
Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities, Noncurrent	80.0	12.5
Commercial Paper [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	37.6	0.5
Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	106.0	3.5
Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	90.6	101.2
U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	98.9	106.5
State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	3.6	4.9
Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	5.7	5.8
Mortgage and Other Asset-backed Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	11.8
Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	24.6	1.6
Foreign Government Short-term Debt Securities | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	8.5
Certificates of Deposit | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	6.2
Fair Value, Inputs, Level 1 [Member]
Assets:
Total Assets	4,124.9	2,859.6
Liabilities:
Financial Liabilities Fair Value Disclosure	14.2	1.1
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	3,965.9	2,686.6
Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Equity Securities, FV-NI	59.8	66.5
Total short-term investments	59.8	66.5
Fair Value, Inputs, Level 1 [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets, current	0.3	0.0
Fair Value, Inputs, Level 1 [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	98.9	106.5
Fair Value, Inputs, Level 1 [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets, Noncurrent	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities, Current	14.1	1.1
Fair Value, Inputs, Level 1 [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities, Noncurrent	0.1	0.0
Fair Value, Inputs, Level 1 [Member] | Commercial Paper [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	98.9	106.5
Fair Value, Inputs, Level 1 [Member] | State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Mortgage and Other Asset-backed Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0
Fair Value, Inputs, Level 1 [Member] | Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 1 [Member] | Foreign Government Short-term Debt Securities | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0
Fair Value, Inputs, Level 1 [Member] | Certificates of Deposit | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0
Fair Value, Inputs, Level 2 [Member]
Assets:
Total Assets	407.2	150.6
Liabilities:
Financial Liabilities Fair Value Disclosure	87.1	17.1
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	0.0	0.0
Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	170.1	4.0
Equity Securities, FV-NI	0.0	0.0
Total short-term investments	170.1	4.0
Fair Value, Inputs, Level 2 [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets, current	20.4	12.6
Fair Value, Inputs, Level 2 [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	118.8	107.7
Fair Value, Inputs, Level 2 [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets, Noncurrent	97.9	26.3
Fair Value, Inputs, Level 2 [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities, Current	7.2	4.6
Fair Value, Inputs, Level 2 [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities, Noncurrent	79.9	12.5
Fair Value, Inputs, Level 2 [Member] | Commercial Paper [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	37.6	0.5
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	106.0	3.5
Fair Value, Inputs, Level 2 [Member] | Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	90.6	101.2
Fair Value, Inputs, Level 2 [Member] | U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 2 [Member] | State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	3.6	4.9
Fair Value, Inputs, Level 2 [Member] | Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 2 [Member] | Mortgage and Other Asset-backed Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	11.8
Fair Value, Inputs, Level 2 [Member] | Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	24.6	1.6
Fair Value, Inputs, Level 2 [Member] | Foreign Government Short-term Debt Securities | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	8.5
Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	6.2
Fair Value, Inputs, Level 3 [Member]
Assets:
Total Assets	5.7	5.8
Liabilities:
Financial Liabilities Fair Value Disclosure	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Assets:
Cash and cash equivalents	0.0	0.0
Fair Value, 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
Fair Value, Inputs, Level 3 [Member] | Prepaid Expenses and Other Current Assets [Member]
Assets:
Derivative assets, current	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	5.7	5.8
Fair Value, Inputs, Level 3 [Member] | Other Long-Term Assets [Member]
Assets:
Derivative assets, Noncurrent	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Accrued Liabilities [Member]
Liabilities:
Derivative liabilities, Current	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Other Long-Term Liabilities [Member]
Liabilities:
Derivative liabilities, Noncurrent	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Commercial Paper [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Corporate Debt Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | U.S. Government Treasury Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | State and Local Government Obligations [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Auction Rate Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	5.7	5.8
Fair Value, Inputs, Level 3 [Member] | Mortgage and Other Asset-backed Securities [Member] | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0
Fair Value, Inputs, Level 3 [Member] | Mortgage and Other Asset-backed Securities [Member] | Long-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0	$ 0.0
Fair Value, Inputs, Level 3 [Member] | Foreign Government Short-term Debt Securities | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	0.0
Fair Value, Inputs, Level 3 [Member] | Certificates of Deposit | Short-term Investments [Member]
Assets:
Debt Securities, Available-for-sale	$ 0.0