Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Federal:
Current	$ 209.0	$ 185.2	$ 242.2
Deferred	(122.7)	(137.0)	(212.5)
Federal, Total	86.3	48.2	29.7
State:
Current	16.6	3.5	22.1
Deferred	(22.7)	(11.0)	(24.7)
State, Total	(6.1)	(7.5)	(2.6)
Foreign:
Current	14.7	5.7	9.6
Deferred	(10.4)	(0.8)	(5.9)
Foreign, Total	4.3	4.9	3.7
Provision for income taxes	$ 84.5	$ 45.6	$ 30.8