Derivative Instruments - Effect of Derivative Instruments Not Designated as Hedges on Consolidated Statement of Operations Summary (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 25, 2020	Jan. 26, 2019	Jan. 25, 2020	Jan. 26, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 1	$ 3	$ 2	$ 3
Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	0	0	2	(1)
Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	0	(1)	1	(1)
Derivatives not designated as hedging instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	42	(15)	37	(71)
Derivatives not designated as hedging instruments: | Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	(2)	(1)	(9)	(28)
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	(3)	(4)	(7)	(8)
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	40	(9)	44	(33)
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	4	(1)	4	(3)
Derivatives not designated as hedging instruments: | Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 3	$ 0	$ 5	$ 1