Commitments and Contingencies (Schedule of Financing Guarantees Outstanding) (Details) (USD $) In Millions, unless otherwise specified	Jan. 24, 2015	Jul. 26, 2014
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	$ 471	$ 465
Deferred revenue associated with financing guarantees:	(269)	(293)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	202	172
Channel partner
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	316	263
Deferred revenue associated with financing guarantees:	(148)	(127)
End user
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	155	202
Deferred revenue associated with financing guarantees:	$ (121)	$ (166)