Leases (Maturity of Lease Liabilities) (Details) - USD ($) $ in Millions	Oct. 27, 2019	Jul. 28, 2019
Operating Lease, Liability	$ 277
Finance Lease, Liability	10
Continuing Operations [Member]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	54
Lessee, Operating Lease, Liability, Payments, Due Year Two	60
Lessee, Operating Lease, Liability, Payments, Due Year Three	40
Lessee, Operating Lease, Liability, Payments, Due Year Four	29
Lessee, Operating Lease, Liability, Payments, Due Year Five	22
Lessee, Operating Lease, Liability, Payments, Due after Year Five	88
Lessee, Operating Lease, Liability, Payments, Due, Total	293
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	30
Operating Lease, Liability	263
Finance Lease, Liability, Payments, Due Next Twelve Months	0
Finance Lease, Liability, Payments, Due Year Two	1
Finance Lease, Liability, Payments, Due Year Three	2
Finance Lease, Liability, Payments, Due Year Four	0
Finance Lease, Liability, Payments, Due Year Five	0
Finance Lease, Liability, Payments, Due after Year Five	0
Finance Lease, Liability, Payment, Due, Total	3
Finance Lease, Liability, Undiscounted Excess Amount	0
Finance Lease, Liability	3
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member]
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	4
Lessee, Operating Lease, Liability, Payments, Due Year Two	4
Lessee, Operating Lease, Liability, Payments, Due Year Three	3
Lessee, Operating Lease, Liability, Payments, Due Year Four	2
Lessee, Operating Lease, Liability, Payments, Due Year Five	1
Lessee, Operating Lease, Liability, Payments, Due after Year Five	0
Lessee, Operating Lease, Liability, Payments, Due, Total	14
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	0
Operating Lease, Liability	14
Finance Lease, Liability, Payments, Due Next Twelve Months	1
Finance Lease, Liability, Payments, Due Year Two	1
Finance Lease, Liability, Payments, Due Year Three	1
Finance Lease, Liability, Payments, Due Year Four	1
Finance Lease, Liability, Payments, Due Year Five	1
Finance Lease, Liability, Payments, Due after Year Five	5
Finance Lease, Liability, Payment, Due, Total	10
Finance Lease, Liability, Undiscounted Excess Amount	3
Finance Lease, Liability	$ 7
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		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		$ 21