Restructuring and Severance Charges - Restructuring Activities and Accrued Liabilities in the Consolidated Balance Sheets (Detail) $ in Millions	12 Months Ended
	Sep. 27, 2015 USD ($)
Restructuring Cost and Reserve [Line Items]
Beginning Balance	$ 3.8
Ending Balance	3.4
Employee Severance
Restructuring Cost and Reserve [Line Items]
Provisions	(10.6)
Contract Termination Costs
Restructuring Cost and Reserve [Line Items]
Provisions	(2.6)
Other Associated Costs
Restructuring Cost and Reserve [Line Items]
Provisions	(3.9)
Other Facilities
Restructuring Cost and Reserve [Line Items]
Beginning Balance	12.3
Provisions	(17.1)
Cash expenditures	(19.5)
Other non-cash settlement	(2.2)
Ending Balance	6.2
Other Facilities | Employee Severance
Restructuring Cost and Reserve [Line Items]
Beginning Balance	4.1
Cash expenditures	(11.3)
Other non-cash settlement	0.0
Ending Balance	2.9
Other Facilities | Contract Termination Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance	8.2
Cash expenditures	(5.9)
Other non-cash settlement	(0.6)
Ending Balance	3.2
Other Facilities | Other Associated Costs
Restructuring Cost and Reserve [Line Items]
Beginning Balance	0.0
Cash expenditures	(2.2)
Other non-cash settlement	(1.6)
Ending Balance	$ 0.1