Commitments and Contingencies (Schedule of Financing Guarantees Outstanding) (Details) - USD ($) $ in Millions	Jan. 26, 2019	Jul. 28, 2018
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	$ 363	$ 308
Deferred revenue associated with financing guarantees:	(86)	(122)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	277	186
Channel partner
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	338	277
Deferred revenue associated with financing guarantees:	(67)	(94)
End user
Loss Contingencies [Line Items]
Maximum potential future payments relating to financing guarantees:	25	31
Deferred revenue associated with financing guarantees:	$ (19)	$ (28)