Other Financial Information - Contracts with Customers (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Deferred Revenue Arrangement [Line Items]
Unbilled receivables - current	$ 306.2	$ 346.7
Unbilled receivables - long-term	68.6	35.1
Deferred revenues - current	(782.2)	(766.0)
Deferred revenues - long-term	(68.5)	(73.1)
Total net unbilled receivables (deferred revenues)	(475.9)	(457.3)
Increase (decrease) in unbilled receivables	11.2	71.1	$ 0.8
Increase in deferred revenue	(11.6)
Deferred revenues recognized	663.1	$ 619.2
Unbilled Revenues
Deferred Revenue Arrangement [Line Items]
Increase (decrease) in unbilled receivables	$ (7.0)