Commitments and Contingencies (Schedule of Financing Guarantees Outstanding) (Details) - USD ($) $ in Millions	Jan. 28, 2017	Jul. 30, 2016
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	$ 412	$ 377
Deferred revenue associated with financing guarantees:	(162)	(161)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	250	216
Channel partner
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	318	281
Deferred revenue associated with financing guarantees:	(99)	(85)
End user
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	94	96
Deferred revenue associated with financing guarantees:	$ (63)	$ (76)