Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jan. 23, 2021	Jan. 25, 2020	Jan. 23, 2021	Jan. 25, 2020	Jul. 25, 2020
Leases [Abstract]
Weighted-average remaining lease term (in years)	4 years 2 months 12 days		4 years 2 months 12 days		4 years
Weighted-average discount rate	1.00%		1.00%		1.50%
Sales-type lease terms, on average	4 years		4 years
Interest income, lease receivables	$ 19	$ 23	$ 40	$ 49
Operating lease income	$ 40	$ 50	$ 83	$ 94