Stockholder's Equity (Share Based Compensation) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 27, 2020	Mar. 29, 2019	Mar. 27, 2020	Mar. 29, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Document Period End Date			Mar. 27, 2020
Share-based compensation expense	$ 40.2	$ 21.8	$ 73.8	$ 42.6
Cost of sales [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	7.2	3.3	11.4	6.9
Research and development [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	17.2	9.9	32.0	22.4
Selling, general and administrative [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense	$ 15.8	$ 8.6	$ 30.4	$ 13.3