Derivative Instruments - Effect of Derivative Instruments Not Designated as Hedges on Consolidated Statement of Operations Summary (Details) - USD ($) $ in Millions	3 Months Ended
	Oct. 26, 2019	Oct. 27, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 1	$ 0
Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	2	(1)
Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	1	0
Derivatives not designated as hedging instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	(5)	(56)
Derivatives not designated as hedging instruments: | Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	(7)	(27)
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	(4)	(4)
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | Operating expenses
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	4	(24)
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	0	(2)
Derivatives not designated as hedging instruments: | Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 2	$ 1