OTHER FINANCIAL INFORMATION - Unbilled Receivables and Deferred Revenues from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 03, 2020	Dec. 28, 2018	Sep. 27, 2019
Other Financial Information [Abstract]
Unbilled receivables - current	$ 315.8		$ 346.7
Unbilled receivables - long-term	42.7		35.1
Deferred revenues - current	(817.9)		(766.0)
Deferred revenues - long-term	(78.9)		(73.1)
Total net unbilled receivables (deferred revenues)	(538.3)		$ (457.3)
Decrease in unbilled receivables	23.3
Increase in deferred revenue	57.7
Recognized revenue included in deferred revenue balance	$ 314.5	$ 263.4