Borrowings (Short-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	Jan. 28, 2012	Jul. 30, 2011
Short-term Debt [Line Items]
Short-term debt, Weighted-Average Interest Rate
Short-term debt	$ 605	$ 588
Other Notes And Borrowings [Member]
Short-term Debt [Line Items]
Short-term debt, Weighted-Average Interest Rate	5.98%	4.59%
Short-term debt	105	88
Commercial Paper [Member]
Short-term Debt [Line Items]
Short-term debt, Weighted-Average Interest Rate	0.12%	0.14%
Short-term debt	$ 500	$ 500