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		6 Months Ended
	Jan. 25, 2014	Jan. 26, 2013	Jan. 25, 2014	Jan. 26, 2013
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (38)	$ (19)	$ 33	$ 57
Foreign Currency Derivatives | Other income (loss), net
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	(63)	(41)	(20)	12
Total Return Swap Deferred Compensation [Member] | Operating Expenses
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	12	19	29	33
Equity Derivatives | Other income (loss), net
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 13	$ 3	$ 24	$ 12