Retirement Plans - Schedule of Net Periodic Benefit Costs (Detail) - Defined Benefit Plans - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Oct. 02, 2015	Sep. 26, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 6.1	$ 5.7	$ 4.1
Interest cost	4.1	4.4	6.1
Loss due to settlement	1.0	1.1	1.8
Expected return on assets	(6.8)	(7.1)	(7.8)
Amortization of prior service cost	(0.1)	0.1	0.2
Recognized actuarial loss	2.9	2.5	2.1
Net periodic benefit cost	7.2	6.7	6.5
New prior service credit	(1.2)	(1.1)	0.0
Net loss arising during the year	25.6	6.7	10.3
Amortization of prior service credit (cost)	0.1	(0.1)	(0.2)
Amortization, settlement and curtailment of net actuarial loss	(3.9)	(3.6)	(3.9)
Total recognized in other comprehensive loss	20.6	1.9	6.2
Total recognized in net periodic benefit cost and other comprehensive loss	$ 27.8	$ 8.6	$ 12.7