Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Allowance for doubtful accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 3.6	$ 2.2	$ 2.4
Charged to Income	0.3	1.2	0.0
Additions and Other	0.0	0.0	0.0
Deductions	0.1	0.2	(0.2)
Balance at End of Period	4.0	3.6	2.2
Sales reserve accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	396.4	402.2	284.2
Charged to Income	2,030.8	2,177.4	1,710.6
Additions and Other	0.0	1.3	30.6
Deductions	(2,049.2)	(2,184.5)	(1,623.2)
Balance at End of Period	378.0	396.4	402.2
Tax valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	233.0	76.9	28.3
Charged to Income	315.7	155.4	33.9
Additions and Other	15.8	0.2	14.7
Deductions	0.4	0.5	0.0
Balance at End of Period	$ 564.9	$ 233.0	$ 76.9