Reconciliation for Assets and Liabilities Measured and Recorded at Fair Value on Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 27, 2014
Available-For Sale Corporate Debt Security
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 62.7
Additions	44.8	[1]
Sale of a portion of available-for-sale corporate debt security	(38.1)	[2]
Ending balance	69.4
Contingent Consideration
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	(2.5)
Additions	(2.9)	[1]
Settlements	0.6	[3]
Change in fair value recognized in earnings	0.6
Ending balance	(4.2)
Option to Purchase a Privately-Held Company
Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	1.4
Change in fair value recognized in earnings	$ (1.4)

[1] Amounts reported under Available-For-Sale Corporate Debt Securities include accrued interest

[2] Refer to Note 16 “CPTC Loans”

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