Derivative Instruments (Schedule Of Notional Amounts Of Derivatives Outstanding) (Details) (USD $) In Millions, unless otherwise specified	Jan. 24, 2015	Jul. 26, 2014
Derivative [Line Items]
Derivatives	$ 14,913	$ 15,557
Derivatives designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	1,641	1,618
Derivatives designated as hedging instruments: | Interest rate derivatives
Derivative [Line Items]
Derivatives	10,400	10,400
Derivatives designated as hedging instruments: | Net investment hedging instruments
Derivative [Line Items]
Derivatives	216	345
Derivatives designated as hedging instruments: | Equity derivatives
Derivative [Line Items]
Derivatives	238	238
Derivatives not designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	1,969	2,528
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation
Derivative [Line Items]
Derivatives	$ 449	$ 428