Shareholders' Equity - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	12 Months Ended		1 Months Ended
	Jul. 28, 2012	Jul. 30, 2011	Aug. 14, 2012 Dividend Declared
Shareholders Equity [Line Items]
Authorized common stock repurchase amount	$ 82,000,000,000
Remaining authorized repurchase amount	5,900,000,000
Cash dividends paid per common share	$ 0.28	$ 0.12
Cash dividends paid	1,501,000,000	658,000,000
Dividend declared per common share to be paid	$ 0.28	$ 0.12	$ 0.14
Dividend declared date			Aug. 14, 2012
Dividend payable date			Oct. 28, 2012
Shares repurchased in settlement of employee tax withholding obligations	12	10
Dollar value of shares repurchased in settlement of employee tax withholding obligations	$ 200,000,000	$ 183,000,000