Employee Stock Award and Benefit Plans - Deferred Compensation Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 03, 2020	Sep. 28, 2019	Sep. 29, 2018
Share-based Payment Arrangement [Abstract]
Gain (loss) on deferred compensation plan investments	$ 6.1	$ 1.1	$ 4.8
Deferred compensation arrangement with individual, expense (benefit)	$ 5.3	$ 1.5	$ 5.2