Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016		Oct. 02, 2015	Oct. 03, 2014
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 0.4		$ 0.8	$ 0.5
Charged to Cost and Expenses	0.1		(0.4)	0.2
Deductions	0.0		0.0	0.1
Misc.	0.0	[1]	0.0	0.0	[1]
Ending Balance	0.5		0.4	0.8
Allowance for Sales Returns [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	12.2		14.1	4.7
Charged to Cost and Expenses	16.1		16.0	12.7
Deductions	(16.0)		(17.9)	(3.3)
Misc.	0.0	[1]	0.0	0.0	[1]
Ending Balance	12.3		12.2	14.1
Valuation Allowance of Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	65.2		60.8	51.0
Charged to Cost and Expenses	13.9		3.6	7.1
Deductions	0.0		0.0	0.0
Misc.	0.0	[1]	0.8	2.7	[1]
Ending Balance	$ 79.1		$ 65.2	$ 60.8

[1] Includes acquired balances