BALANCE SHEET COMPONENTS - Unbilled Receivables and Deferred Revenues from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 29, 2018	Jun. 30, 2017	Jun. 29, 2018	Jun. 30, 2017	Sep. 29, 2017
Balance Sheet Components [Abstract]
Unbilled receivables - current	$ 343.0		$ 343.0		$ 259.1
Unbilled receivables - long-term (1)	27.4		27.4		10.9
Deferred revenues - current	(790.2)		(790.2)		(755.4)
Deferred revenues - long-term (2)	(9.6)		(9.6)		(7.2)
Total net unbilled receivables (deferred revenues)	(429.4)		(429.4)		$ (492.6)
Increase in deferred revenues net of unbilled receivables			63.2
Recognized revenue included in deferred revenue balance	$ 214.3	$ 109.0	519.5	$ 455.0
Impairment loss on non-current unbilled receivable			$ 0.0	$ 17.2