Borrowings (Short-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	Jul. 30, 2011	Jul. 31, 2010
Short-term debt, weighted-average interest rate
Short-term debt	$ 588	$ 3,096
Notes Payable, Other Payables [Member]
Short-term debt, weighted-average interest rate	4.59%	4.21%
Short-term debt	88	59
Commercial Paper [Member]
Short-term debt, weighted-average interest rate	0.14%
Short-term debt	500
Current Portion Of Long-Term Debt [Member]
Short-term debt, weighted-average interest rate		3.12%
Short-term debt		$ 3,037