Shareholders' Equity (Stock Repurchase Program) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Oct. 26, 2013
Stock Repurchase Program [Roll Forward]
Cumulative shares repurchased, beginning balance	3,868
Repurchase of common stock under the stock repurchase program	84
Cumulative shares repurchased, ending balance	3,952
Cumulative weighted-average price per share, beginning balance	$ 20.40
Weighted Average Price Per Share Of Stock Repurchased In Period	$ 23.65
Cumulative weighted-average price per share, ending balance	$ 20.47
Cumulative amount repurchased, beginning balance	$ 78,906
Repurchase of common stock under the stock repurchase program, amount	2,000
Cumulative amount repurchased, ending balance	$ 80,906