Income Taxes - Income Before Provision for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Apr. 25, 2020	Apr. 27, 2019	Apr. 25, 2020	Apr. 27, 2019
Income Tax Disclosure [Abstract]
Income before provision for income taxes	$ 3,444	$ 3,615	$ 10,664	$ 10,867
Provision for income taxes	$ 670	$ 571	$ 2,086	$ 1,452
Effective tax rate	19.40%	15.80%	19.60%	13.40%