Income Taxes (Income Before Provision For Income Taxes) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 25, 2014	Jan. 26, 2013	Jan. 25, 2014	Jan. 26, 2013
Income Tax Disclosure [Abstract]
Income before provision for income taxes	$ 1,755	$ 2,780	$ 4,295	$ 5,411
Provision for (benefit from) income taxes	$ 326	$ (363)	$ 870	$ 176
Effective tax rate	18.60%	(13.10%)	20.30%	3.30%