Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended
	Jan. 26, 2013	Jan. 26, 2013	Jul. 28, 2012
Income Tax Disclosure [Abstract]
Tax benefits and R&D tax credit		$ 926,000,000
Increase (Decrease) in Income Taxes Receivable	733,000,000
Tax Adjustments, Settlements, and Unusual Provisions	794,000,000
Income Tax Examination, Penalties and Interest Expense	157,000,000
Unrecognized Tax Benefits, Decreases Resulting from Settlements with Taxing Authorities	1,000,000,000
Tax amounts previously paid to tax authorities became refundable	154,000,000
Unrecognized Tax Benefits	1,900,000,000	1,900,000,000
Unrecognized tax benefits that would impact tax rate	1,600,000,000	1,600,000,000
Income Tax Reconciliation, Tax Credits, Research	$ 132,000,000		$ 72,000,000