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	12 Months Ended
	Jul. 28, 2018	Jul. 29, 2017	Jul. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	$ 15	$ 82	$ 1
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	(24)	13	(19)
Total return swaps—deferred compensation | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	(11)	0	0
Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	50	53	6
Total return swaps—deferred compensation | Cost of sales | Product
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	1	2	0
Total return swaps—deferred compensation | Cost of sales | Service
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	3	3	1
Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE YEARS ENDED	$ (4)	$ 11	$ 13