Leases - Additional Information (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jan. 25, 2020 USD ($)	Jan. 25, 2020 USD ($)
Leases [Abstract]
Operating lease right-of-use asset	$ 1,000	$ 1,000
Operating lease liabilities	1,078	1,078
Operating lease liabilities, current	380	380
Operating lease liabilities, noncurrent	$ 698	$ 698
Weighted-average remaining lease term (in years)	4 years 1 month 6 days	4 years 1 month 6 days
Weighted-average discount rate	1.80%	1.80%
Sales-type lease terms, on average	4 years	4 years
Interest income, lease receivables	$ 23	$ 49
Operating lease income	$ 50	$ 94