Derivative Instruments (Effect Of Derivative Instruments Not Designated As Hedges On Consolidated Statement Of Operations Summary) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Oct. 26, 2013	Oct. 27, 2012
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 71	$ 76
Foreign Exchange Contract | Other income (loss), net [Member]
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	43	53
Total Return Swaps-Deferred Compensation [Member] | Operating Expenses [Member]
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	17	14
Equity Derivatives [Member] | Other income (loss), net [Member]
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 11	$ 9