Shareholders' Equity - Additional Information (Detail) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 26, 2013	Jan. 28, 2012	Jan. 26, 2013	Jan. 28, 2012
Shareholders Equity [Line Items]
Adjustments Related to Tax Withholding for Share-based Compensation			$ 212,000,000	$ 145,000,000
Shares Paid for Tax Withholding for Share Based Compensation			11	9
Payments of Dividends			1,487,000,000	644,000,000
Cash dividends declared per common share (in dollars per share)	$ 0.14	$ 0.06	$ 0.28	$ 0.12
Remaining Aggregate Authorized Common Stock Repurchase	5,100,000,000		5,100,000,000
Aggregate Authorized Common Stock Repurchase	82,000,000,000		82,000,000,000
Stockholder Equity Excluding Portion Attributable To Noncontrolling Interest [Member]
Shareholders Equity [Line Items]
Payments of Dividends			$ 1,487,000,000	$ 644,000,000