Derivative Instruments (Schedule of Notional Amounts of Derivatives Outstanding) (Details) - USD ($)	Apr. 28, 2018	Jul. 29, 2017
Derivative [Line Items]
Derivatives	$ 10,585,000,000	$ 11,590,000,000
Derivatives designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	326,000,000	1,696,000,000
Derivatives designated as hedging instruments: | Interest rate derivatives
Derivative [Line Items]
Derivatives	6,750,000,000	6,750,000,000
Derivatives designated as hedging instruments: | Net investment hedging instruments
Derivative [Line Items]
Derivatives	455,000,000	351,000,000
Derivatives designated as hedging instruments: | Equity derivatives
Derivative [Line Items]
Derivatives	302,000,000	0
Derivatives not designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	2,199,000,000	2,258,000,000
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation
Derivative [Line Items]
Derivatives	$ 553,000,000	$ 535,000,000