Schedule of Amounts Recognized in Accumulated Other Comprehensive Loss before Tax (Detail) (USD $) In Millions, unless otherwise specified	Sep. 28, 2012	Sep. 30, 2011
Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	$ (0.4)	$ (0.6)
Net gain (loss)	(59.7)	(53.3)
Accumulated other comprehensive loss	(60.1)	(53.9)
Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net gain (loss)	(0.4)	(0.6)
Accumulated other comprehensive loss	$ (0.4)	$ (0.6)