Financing Receivables And Guarantees (Schedule Of Financing Guarantees Outstanding) (Details) (USD $) In Millions, unless otherwise specified	Apr. 28, 2012	Jul. 30, 2011
Guarantor Obligations [Line Items]
Maximum potential future payments relating to financing guarantees	$ 541	$ 613
Deferred revenue associated with financing guarantees	(433)	(496)
Maximum potential future payments relating to financing guarantees, net of associated deferred revenue	108	117
Channel Partner [Member]
Guarantor Obligations [Line Items]
Maximum potential future payments relating to financing guarantees	283	336
Deferred revenue associated with financing guarantees	(209)	(248)
End User [Member]
Guarantor Obligations [Line Items]
Maximum potential future payments relating to financing guarantees	258	277
Deferred revenue associated with financing guarantees	$ (224)	$ (248)