Derivative Instruments (Schedule of Notional Amounts of Derivatives Outstanding) (Details) - USD ($)	Jan. 26, 2019	Jul. 28, 2018
Derivative [Line Items]
Derivatives	$ 11,118,000,000	$ 10,011,000,000
Derivatives designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	890,000,000	147,000,000
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	299,000,000	250,000,000
Derivatives not designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Derivatives	2,643,000,000	2,298,000,000
Derivatives not designated as hedging instruments: | Total return swaps—deferred compensation
Derivative [Line Items]
Derivatives	$ 536,000,000	$ 566,000,000