Derivative Instruments (Effect Of Derivative Instruments Not Designated As Hedges On Consolidated Statement Of Operations Summary) (Details) - Derivatives not designated as hedging instruments: - USD ($) $ in Millions	3 Months Ended
	Oct. 24, 2015	Oct. 25, 2014
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE THREE MONTHS ENDED	$ (2)	$ (75)
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE THREE MONTHS ENDED	4	(58)
Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE THREE MONTHS ENDED	(16)	(13)
Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE THREE MONTHS ENDED	$ 10	$ (4)