OTHER FINANCIAL INFORMATION - Unbilled Receivables and Deferred Revenues from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 29, 2019	Mar. 30, 2018	Mar. 29, 2019	Mar. 30, 2018	Sep. 28, 2018
Other Financial Information [Abstract]
Unbilled receivables - current	$ 333.6		$ 333.6		$ 362.8
Unbilled receivables - long-term (1)	60.5		60.5		36.3
Deferred revenues - current	(757.9)		(757.9)		(729.7)
Deferred revenues - long-term (2)	(65.7)		(65.7)		(38.6)
Total net unbilled receivables (deferred revenues)	(429.5)		(429.5)		$ (369.2)
Decrease in unbilled receivables net of deferred revenues			(60.3)
Recognized revenue included in deferred revenue balance	$ 124.4	$ 107.4	$ 337.8	$ 300.5

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Other Financial Information [Abstract]

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