Commitments and Contingencies - Accrued Product Warranty (Detail) - USD ($) $ in Millions	12 Months Ended
	Oct. 02, 2015	Sep. 26, 2014
Commitments and Contingencies Disclosure [Abstract]
Accrued product warranty, at beginning of period	$ 45.9	$ 49.3
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Charged to cost of revenues	50.8	51.9
Actual product warranty expenditures	(54.2)	(55.8)
Accrued product warranty, at end of period	$ 49.3	$ 53.2