Valuation and Qualifying Accounts - Schedule II Valuation and Qualifying Accounts (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 26, 2014
Allowance for doubtful accounts receivable
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 21.2	$ 20.3	$ 14.7
Charged to Bad Debt Expense	3.5	1.1	7.2
Write-offs Adjustments Charged to Allowance	(0.3)	(0.2)	(1.6)
Balance at End of Period	24.4	21.2	20.3
Valuation allowance for deferred tax assets
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	69.7	67.5	60.7
Increases	12.2	4.7	8.3
Deductions	(2.3)	(2.5)	(1.5)
Balance at End of Period	$ 79.6	$ 69.7	$ 67.5