Derivative Instruments (Schedule Of Notional Amounts Of Derivatives Outstanding) (Details) (USD $) In Millions, unless otherwise specified	Jan. 25, 2014	Jul. 27, 2013
Derivative [Line Items]
Notional amount of derivatives	$ 11,882	$ 12,992
Designated as Hedging Instrument | Foreign Currency Derivatives
Derivative [Line Items]
Notional amount of derivatives	1,082	1,885
Designated as Hedging Instrument | Interest Rate Derivatives
Derivative [Line Items]
Notional amount of derivatives	6,250	5,250
Designated as Hedging Instrument | Net Investment Hedging
Derivative [Line Items]
Notional amount of derivatives	681	662
Designated as Hedging Instrument | Equity [Member]
Derivative [Line Items]
Notional amount of derivatives	238	1,098
Derivatives Not Designated As Hedging Instruments | Foreign Currency Derivatives
Derivative [Line Items]
Notional amount of derivatives	3,225	3,739
Derivatives Not Designated As Hedging Instruments | Total Return Swap [Member]
Derivative [Line Items]
Notional amount of derivatives	$ 406	$ 358