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. 28, 2017	Oct. 29, 2016
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ 24	$ (18)
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	7	(16)
Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	16	(3)
Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ 1	$ 1