Schedule of Assumptions used to Measure Benefit Obligations for Company's Defined Benefit Pension and Post Retirement Benefit Plans (Detail)	Sep. 26, 2014	Sep. 27, 2013
Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	2.77%	3.11%
Rate of compensation increase	2.45%	2.51%
Post-Retirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.10%	3.80%

Expected rate of compensation increases (for pay-related plans).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(2)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant