Leases - Additional Information (Details) $ in Millions	3 Months Ended
	Oct. 26, 2019 USD ($)
Leases [Abstract]
Operating lease right-of-use asset	$ 1,100
Operating lease liabilities	1,147
Operating lease liabilities, current	367
Operating lease liabilities, noncurrent	$ 780
Sales-type lease terms, on average	4 years
Interest income, lease receivables	$ 26
Operating lease income	$ 44