Income Taxes - Income Before Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2021	Jan. 25, 2020	Jan. 23, 2021	Jan. 25, 2020
Income Tax Disclosure [Abstract]
Income before provision for income taxes	$ 3,255	$ 3,534	$ 5,936	$ 7,220
Provision for income taxes	$ 710	$ 656	$ 1,217	$ 1,416
Effective tax rate	21.80%	18.60%	20.50%	19.60%