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. 24, 2020	Oct. 26, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 42	$ (5)
Foreign currency derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	14	(7)
Total return swaps—deferred compensation | Operating expenses and other
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	23	0
Equity derivatives | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Total gains (losses)	$ 5	$ 2