Leases (Maturity of Lease Liabilities) (Details) - USD ($) $ in Millions	Jan. 26, 2020	Jul. 28, 2019
Operating Lease, Liability	$ 263
Finance Lease, Liability	5
Continuing Operations [Member]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	38
Lessee, Operating Lease, Liability, Payments, Due Year Two	63
Lessee, Operating Lease, Liability, Payments, Due Year Three	42
Lessee, Operating Lease, Liability, Payments, Due Year Four	31
Lessee, Operating Lease, Liability, Payments, Due Year Five	24
Lessee, Operating Lease, Liability, Payments, Due after Year Five	94
Lessee, Operating Lease, Liability, Payments, Due, Total	292
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	29
Operating Lease, Liability	263
Finance Lease, Liability, Payments, Due Next Twelve Months	1
Finance Lease, Liability, Payments, Due Year Two	1
Finance Lease, Liability, Payments, Due Year Three	2
Finance Lease, Liability, Payments, Due Year Four	1
Finance Lease, Liability, Payments, Due Year Five	0
Finance Lease, Liability, Payments, Due after Year Five	0
Finance Lease, Liability, Payment, Due, Total	5
Finance Lease, Liability, Undiscounted Excess Amount	0
Finance Lease, Liability	$ 5
Previous Accounting Guidance | Continuing Operations [Member]
Operating Leases, Future Minimum Payments Due, Next Twelve Months		$ 61
Operating Leases, Future Minimum Payments, Due in Two Years		48
Operating Leases, Future Minimum Payments, Due in Three Years		36
Operating Leases, Future Minimum Payments, Due in Four Years		26
Operating Leases, Future Minimum Payments, Due in Five Years		20
Operating Leases, Future Minimum Payments, Due Thereafter		88
Operating Leases, Future Minimum Payments Due, Total		279
Previous Accounting Guidance | Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Operating Leases, Future Minimum Payments Due, Next Twelve Months		7
Operating Leases, Future Minimum Payments, Due in Two Years		6
Operating Leases, Future Minimum Payments, Due in Three Years		4
Operating Leases, Future Minimum Payments, Due in Four Years		3
Operating Leases, Future Minimum Payments, Due in Five Years		1
Operating Leases, Future Minimum Payments, Due Thereafter		0
Operating Leases, Future Minimum Payments Due, Total		$ 21