Commitments and Contingencies (Schedule of Financing Guarantees Outstanding) (Details) - USD ($) $ in Millions	Apr. 30, 2016	Jul. 25, 2015
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	$ 332	$ 417
Deferred revenue associated with financing guarantees:	(180)	(234)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	152	183
Channel partner
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	228	288
Deferred revenue associated with financing guarantees:	(98)	(127)
End user
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	104	129
Deferred revenue associated with financing guarantees:	$ (82)	$ (107)