Commitments and Contingencies (Schedule of Financing Guarantees Outstanding) (Details) - USD ($) $ in Millions	Jan. 27, 2018	Jul. 29, 2017
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	$ 341	$ 314
Deferred revenue associated with financing guarantees:	(131)	(134)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	210	180
Channel partner
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	288	240
Deferred revenue associated with financing guarantees:	(91)	(82)
End user
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	53	74
Deferred revenue associated with financing guarantees:	$ (40)	$ (52)