EMPLOYEE STOCK PLANS - Net Share-Based Compensation Expense (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 28, 2019	Jun. 29, 2018	Jun. 28, 2019	Jun. 29, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 12.2	$ 13.3	$ 35.2	$ 34.5
Income tax benefit for share-based compensation	(2.3)	(3.0)	(6.8)	(7.7)
Cost of revenues - Product
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	0.7	0.8	2.2	2.3
Cost of revenues - Service
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	1.2	1.1	3.3	3.1
Research and development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	1.3	1.2	3.5	3.6
Selling, general and administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation expense	$ 9.0	$ 10.2	$ 26.2	$ 25.5