Reconciliation for Assets and Liabilities Measured and Recorded at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Mar. 28, 2014
Corporate Debt Security
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 62.7
Additions, including accrued interest	16.7
Settlements	0	[1]
Change in fair value recognized in earnings	0
Ending balance	79.4
Option to Purchase a Company
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	1.4
Additions, including accrued interest	0
Settlements	0	[1]
Change in fair value recognized in earnings	0
Ending balance	1.4
Contingent Consideration
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	(2.5)
Additions, including accrued interest	0
Settlements	0.4	[1]
Change in fair value recognized in earnings	0.6
Ending balance	$ (1.5)

[1] Amounts reported under “Contingent Consideration” represent cash payments to settle contingent consideration liabilities.