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		6 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ (15)	$ 106	$ (71)	$ 128
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(1)	66	(28)	73
Total return swaps—deferred compensation | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(4)	(3)	(8)	(5)
Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(9)	39	(33)	54
Total return swaps—deferred compensation | Cost of sales | Product
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	0	1	(1)	1
Total return swaps—deferred compensation | Cost of sales | Service
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	(1)	1	(2)	2
Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
GAINS (LOSSES) FOR THE PERIOD	$ 0	$ 2	$ 1	$ 3