Derivative Instruments (Schedule Of Notional Amounts Of Derivatives Outstanding) (Details) - USD ($)	Jan. 28, 2017	Jul. 30, 2016
Derivative [Line Items]
Derivatives	$ 14,796,000,000	$ 15,414,000,000
Derivatives designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	2,142,000,000	2,683,000,000
Derivatives designated as hedging instruments: | Interest rate derivatives
Derivative [Line Items]
Derivatives	9,900,000,000	9,900,000,000
Derivatives designated as hedging instruments: | Net investment hedging instruments
Derivative [Line Items]
Derivatives	236,000,000	298,000,000
Derivatives not designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	2,002,000,000	2,057,000,000
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation
Derivative [Line Items]
Derivatives	$ 516,000,000	$ 476,000,000