Commitments and Contingencies (Schedule of Other Commitments) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jan. 27, 2018	Jan. 28, 2017	Jan. 27, 2018	Jan. 28, 2017
Acquisition
Contingency [Line Items]
Compensation expense related to acquisitions	$ 46	$ 73	$ 88	$ 137

Amount of labor-related expenses classified as other.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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