Leases (Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	9 Months Ended
	Apr. 26, 2020	Jul. 29, 2019	Jul. 28, 2019
Operating Lease, Payments	$ 59
Finance Lease, Interest Payment on Liability	0
Finance Lease, Principal Payments	1
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	77
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	8
Operating Lease, Right-of-Use Asset divested with businesses sold	18
Finance Leases, Right-of-Use Asset divested with businesses sold	5
Short-term borrowings	1,504		$ 1,371
Accounting Standards Update 2016-02 [Member]
Short-term borrowings	$ (20)	$ (20)