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. 27, 2018	Oct. 28, 2017
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ (56)	$ 22
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(27)	7
Total return swaps—deferred compensation | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(4)	(2)
Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(24)	15
Total return swaps—deferred compensation | Cost of sales | Product
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(1)	0
Total return swaps—deferred compensation | Cost of sales | Service
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(1)	1
Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ 1	$ 1