Leases (Reported in Balance Sheet) (Details) - USD ($) $ in Millions	Jan. 26, 2020	Jul. 28, 2019
Operating Lease, Right-of-Use Asset	$ 267
Finance Lease, Right-of-Use Asset	5
Operating Lease, Liability	263
Finance Lease, Liability, Noncurrent	4	$ 3
Finance Lease, Liability	5
Property, Plant and Equipment [Member]
Operating Lease, Right-of-Use Asset	0
Finance Lease, Right-of-Use Asset	5
Other Assets [Member]
Operating Lease, Right-of-Use Asset	267
Finance Lease, Right-of-Use Asset	0
Short-term Debt [Member]
Operating Lease, Liability, Current	0
Finance Lease, Liability, Current	1
Accrued Liabilities [Member]
Operating Lease, Liability, Current	60
Finance Lease, Liability, Current	0
Long-term Debt [Member]
Operating Lease, Liability, Noncurrent	0
Finance Lease, Liability, Noncurrent	4
Other Liabilities [Member]
Operating Lease, Liability, Noncurrent	203
Finance Lease, Liability, Noncurrent	$ 0