Income Taxes (Schedule of Unrecognized Tax Benefit Activity) (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 25, 2015	Sep. 26, 2014
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance at beginning of fiscal year	$ 89.2	$ 82.0	$ 100.1
Additions related to current year tax positions	63.8	4.5	3.2
Additions related to prior period tax positions	10.8	19.9	30.6
Reductions related to prior period tax positions	(37.8)	(7.7)	(33.0)
Unrecognized Tax Benefits, Decrease Resulting from disposal of business	(6.6)	0.0	0.0
Settlements	(2.6)	(7.8)	(6.9)
Lapse of statute of limitations	(2.0)	(1.7)	(12.0)
Balance at end of fiscal year	$ 114.8	$ 89.2	$ 82.0