v3.26.1
Fair Value Measurements (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($)
$ in Millions
Mar. 29, 2026
Sep. 28, 2025
Assets:    
Total short-term investments $ 168.3 $ 247.2
Derivative assets, Current 24.0 15.9
Derivative assets, Noncurrent 393.3 278.6
Total Assets 2,423.9 4,008.4
Liabilities:    
Derivative liabilities, Current 0.6 7.1
Derivative liabilities, Noncurrent 17.2 20.9
Total liabilities 17.8 28.0
Cash and cash equivalents    
Assets:    
Cash and cash equivalents 1,532.0 3,219.8
Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 91.0 151.9
Marketable equity securities 77.3 95.3
Total short-term investments 168.3 247.2
Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 306.3 246.9
Other Long-Term Investments 306.3 246.9
Corporate debt securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 54.2 67.8
Corporate debt securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 154.6 132.2
Mortgage and other asset-backed securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.7 0.4
Mortgage and other asset-backed securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 71.3 75.7
State and local government obligations | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 3.8 1.1
State and local government obligations | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities:   2.7
U.S. government treasury securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 32.3 82.6
U.S. government treasury securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 80.4 36.3
Fair Value, Inputs, Level 1 [Member]    
Assets:    
Derivative assets, Current 0.0 0.0
Derivative assets, Noncurrent 0.0 0.0
Total Assets 1,722.0 3,434.0
Liabilities:    
Derivative liabilities, Current 0.0 0.0
Derivative liabilities, Noncurrent 0.0 0.0
Total liabilities 0.0 0.0
Fair Value, Inputs, Level 1 [Member] | Cash and cash equivalents    
Assets:    
Cash and cash equivalents 1,532.0 3,219.8
Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 32.3 82.6
Marketable equity securities 77.3 95.3
Total short-term investments 109.6 177.9
Fair Value, Inputs, Level 1 [Member] | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 80.4 36.3
Other Long-Term Investments 80.4 36.3
Fair Value, Inputs, Level 1 [Member] | Corporate debt securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 1 [Member] | Corporate debt securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 1 [Member] | Mortgage and other asset-backed securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 1 [Member] | Mortgage and other asset-backed securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 1 [Member] | State and local government obligations | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 1 [Member] | State and local government obligations | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities:   0.0
Fair Value, Inputs, Level 1 [Member] | U.S. government treasury securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 32.3 82.6
Fair Value, Inputs, Level 1 [Member] | U.S. government treasury securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 80.4 36.3
Fair Value, Inputs, Level 2 [Member]    
Assets:    
Derivative assets, Current 24.0 15.9
Derivative assets, Noncurrent 393.3 278.6
Total Assets 661.4 535.8
Liabilities:    
Derivative liabilities, Current 0.6 7.1
Derivative liabilities, Noncurrent 17.2 20.9
Total liabilities 17.8 28.0
Fair Value, Inputs, Level 2 [Member] | Cash and cash equivalents    
Assets:    
Cash and cash equivalents 0.0 0.0
Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 46.4 57.4
Marketable equity securities 0.0 0.0
Total short-term investments 46.4 57.4
Fair Value, Inputs, Level 2 [Member] | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 197.7 183.9
Other Long-Term Investments 197.7 183.9
Fair Value, Inputs, Level 2 [Member] | Corporate debt securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 41.9 55.9
Fair Value, Inputs, Level 2 [Member] | Corporate debt securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 126.4 105.5
Fair Value, Inputs, Level 2 [Member] | Mortgage and other asset-backed securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.7 0.4
Fair Value, Inputs, Level 2 [Member] | Mortgage and other asset-backed securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 71.3 75.7
Fair Value, Inputs, Level 2 [Member] | State and local government obligations | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 3.8 1.1
Fair Value, Inputs, Level 2 [Member] | State and local government obligations | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities:   2.7
Fair Value, Inputs, Level 2 [Member] | U.S. government treasury securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 2 [Member] | U.S. government treasury securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 3 [Member]    
Assets:    
Derivative assets, Current 0.0 0.0
Derivative assets, Noncurrent 0.0 0.0
Total Assets 40.5 38.6
Liabilities:    
Derivative liabilities, Current 0.0 0.0
Derivative liabilities, Noncurrent 0.0 0.0
Total liabilities 0.0 0.0
Fair Value, Inputs, Level 3 [Member] | Cash and cash equivalents    
Assets:    
Cash and cash equivalents 0.0 0.0
Fair Value, Inputs, Level 3 [Member] | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 12.3 11.9
Marketable equity securities 0.0 0.0
Total short-term investments 12.3 11.9
Fair Value, Inputs, Level 3 [Member] | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 28.2 26.7
Other Long-Term Investments 28.2 26.7
Fair Value, Inputs, Level 3 [Member] | Corporate debt securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 12.3 11.9
Fair Value, Inputs, Level 3 [Member] | Corporate debt securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 28.2 26.7
Fair Value, Inputs, Level 3 [Member] | Mortgage and other asset-backed securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 3 [Member] | Mortgage and other asset-backed securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 3 [Member] | State and local government obligations | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 3 [Member] | State and local government obligations | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities:   0.0
Fair Value, Inputs, Level 3 [Member] | U.S. government treasury securities | Short-term Investments [Member]    
Assets:    
Available-for-sale debt securities: 0.0 0.0
Fair Value, Inputs, Level 3 [Member] | U.S. government treasury securities | Long-term Investments [Member]    
Assets:    
Available-for-sale debt securities: $ 0.0 $ 0.0