Stockholders' Equity (Share Based Expense Allocation) (Details) - USD ($) $ in Millions	12 Months Ended
Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	$ 156.6	$ 80.1	$ 107.8
Share-based compensation tax benefit	10.3	1.6	25.6
Capitalized stock based compensation	10.6	4.7	2.9
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation	23.2	13.0	14.4
Research and Development Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation	68.7	41.6	42.6
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated share-based compensation	$ 64.7	$ 25.5	$ 50.8

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost capitalized for award under share-based payment arrangement.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of noncash expense for share-based payment arrangement.

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