The current carrying amount of the liability for the freestanding or embedded guarantor's obligations under the guarantee or each group of similar guarantees.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 45

-Paragraph 13

-Subparagraph c

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_GuaranteeObligationsCurrentCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jan. 26, 2013	Jan. 26, 2013	Jan. 26, 2013 Credit Agreement, December 3, 2012, Maturing December 2017 Revolving Credit Facility Standby Letters of Credit	Jul. 28, 2012 Prior Credit Agreement Which Has Been Terminated or Replaced Revolving Credit Facility Standby Letters of Credit	Jan. 26, 2013 Performance Guarantee and Surety Bond
Loss Contingencies [Line Items]
Defined Benefit Plan, Contributions by Employer	$ 1	$ 2
Loss Contingency, Estimate [Abstract]
Oustanding performance and other surety contract bonds					432.8
Guarantor Obligations, Maximum Exposure, Undiscounted					149.3
Letters of credit outstanding amount			$ 44.1	$ 38.5