Schedule of Changes in Unrecognized Tax Benefits (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Sep. 28, 2012	Sep. 30, 2011	Oct. 01, 2010
Reconciliation of Unrecognized Tax Benefits [Line Items]
Unrecognized tax benefits balance-beginning of fiscal year	$ 37.1	$ 46.4	$ 58.9
Additions based on tax positions related to a prior year	3.8	1.0	1.4
Reductions based on tax positions related to a prior year	(0.9)	(0.4)	(14.4)
Additions based on tax positions related to the current year	7.1	8.6	7.9
Reductions based on tax positions related to the current year	(0.3)	0	0
Settlements	(0.4)	(5.1)	(7.2)
Reductions resulting from the expiration of the applicable statute of limitations	(7.6)	(13.4)	(0.2)
Unrecognized tax benefits balance-end of fiscal year	$ 38.8	$ 37.1	$ 46.4

The gross amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns as of the balance sheet date.

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