Business Combinations (Additional Information) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jan. 24, 2015	Jan. 25, 2014
Supplementary Information [Line Items]
Number of business combinations (in numbers)	3us-gaap_NumberOfBusinessesAcquired
Acquired Cash and Cash Equivalents	$ 4us-gaap_CashAcquiredFromAcquisition
General and administrative
Supplementary Information [Line Items]
Business Acquisition, Transaction Costs	$ 5	$ 6

The cash inflow associated with the acquisition of business during the period (for example, cash that was held by the acquired business).

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

Name:	us-gaap_CashAcquiredFromAcquisition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration