Supplemental Information Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	Jan. 26, 2013	Jul. 28, 2012
Supplementary Information[Line Items]
Aggregate Authorized Common Stock Repurchase	$ 82,000,000,000
Repurchases of common stock under the repurchase program, shares	3,780	3,740
Repurchases of common stock under the repurchase program, value	76,886,000,000	76,133,000,000
Common Stock [Member]
Supplementary Information[Line Items]
Repurchases of common stock under the repurchase program, shares	3,780
Common Stock Including Additional Paid in Capital [Member]
Supplementary Information[Line Items]
Repurchases of common stock under the repurchase program, value	17,339,000,000
Retained Earnings [Member]
Supplementary Information[Line Items]
Repurchases of common stock under the repurchase program, value	59,547,000,000
Parent [Member]
Supplementary Information[Line Items]
Repurchases of common stock under the repurchase program, value	$ 76,886,000,000