Short-term Borrowings and Long-term Debt (Schedule of Short-term Debt) (Details) $ in Millions, $ in Millions, $ in Millions		Jul. 29, 2018 USD ($)	Jul. 29, 2018 CAD ($)	Jul. 30, 2017 USD ($)	Jul. 30, 2017 AUD ($)
Short-term Debt [Line Items]
Commercial Paper		$ 1,140		$ 874
Capital Lease Obligations, Current		1		1
Debt, Current		1,896		1,037
Variable Interest Rate [Member]
Short-term Debt [Line Items]
Short-term Bank Loans and Notes Payable		22		10
Australian Notes [Member]
Short-term Debt [Line Items]
Short-term Bank Loans and Notes Payable		348		152	$ 190
4.50% notes, due 2019
Short-term Debt [Line Items]
Notes Payable, Current		300		0
Short-term Debt [Member]
Short-term Debt [Line Items]
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net	[1]	(5)		0
Foreign Line of Credit [Member] | Variable Interest Rate [Member]
Short-term Debt [Line Items]
Line of Credit, Current		$ 90	$ 117	$ 0

[1] Includes unamortized net discount/premium on debt issuances and debt issuance costs.