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. 29, 2016	Oct. 24, 2015
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ (18)	$ (2)
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(16)	4
Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(3)	(16)
Equity derivatives/warrants | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ 1	$ 10