Borrowings - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended
	Jan. 25, 2014	Jan. 25, 2014	Jul. 27, 2013
Debt Disclosure
Notional amount of derivatives	$ 11,882,000,000	$ 11,882,000,000	$ 12,992,000,000
Unsecured Revolving Credit Facility	3,000,000,000	3,000,000,000
Unsecured revolving credit facility maturity date		Feb. 17, 2017
Line of Credit Facility, Interest Rate Description		either (i) the higher of the Federal Funds rate plus 0.50%, Bank of America's “prime rate” as announced from time to time, or one-month LIBOR plus 1.00%, or (ii) LIBOR plus a margin that is based on the Company's senior debt credit ratings
Interest Rate- Federal Funds rate plus 0.5%		0.50%
Interest Rate- One-month LIBOR plus 1.00%	1.00%
Available increases under the credit facility	2,000,000,000	2,000,000,000
Additional unsecured revolving credit facility maturity date		Feb. 17, 2019
Up To Limit
Debt Disclosure
ST debt financing program- Commercial paper notes (up to limit)	3,000,000,000	3,000,000,000
Commercial Paper [Member]
Debt Disclosure
Outstanding commercial paper maturity date		three months or less.
Designated as Hedging Instrument | Interest Rate Derivatives
Debt Disclosure
Notional amount of derivatives	$ 6,250,000,000	$ 6,250,000,000	$ 5,250,000,000