Commitments and Contingencies (Schedule of Financing Guarantees Outstanding) (Details) (USD $) In Millions, unless otherwise specified	Apr. 25, 2015	Jul. 26, 2014
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	$ 437	$ 465
Deferred revenue associated with financing guarantees:	(235)	(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:	299	263
Deferred revenue associated with financing guarantees:	(122)	(127)
End user
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	138	202
Deferred revenue associated with financing guarantees:	$ (113)	$ (166)