Summary Stock Option Transactions (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	9 Months Ended
	May 06, 2012 Year
Number of options
Number of options outstanding and exercisable at beginning balance	5,917
Exercised	(1,760)
Number of options outstanding and exercisable at ending balance	4,157
Weighted- average exercise price
Weighted- average exercise price beginning Balance	$ 40.07
Exercised	$ 39.5
Weighted- average exercise price ending balance	$ 40.31
Weighted-average remaining contractual term
Weighted-average remaining contractual term (in years)	2.3
Aggregate intrinsic value
Aggregate intrinsic value	$ 179	[1]

[1] The difference between the exercise price and market value of common stock at May 6, 2012.