Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Apr. 26, 2020	Jan. 26, 2020	Apr. 28, 2019	Apr. 26, 2020	Apr. 28, 2019	Jul. 28, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months				$ 7
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (35)		$ (2)	(26)	$ (6)
Other Current Assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Margin Deposit Assets	18			$ 18		$ 7
Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Contracts Mature Within, Months				18 months
Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Maximum Length of Contract Maturity				18 months
Deferred Compensation Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Maximum Length of Contract Maturity				12 months
Treasury Lock [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	0	$ 3	$ 0	$ 3	$ 0
Derivatives Designated As Hedges [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	118			118		146
Derivatives Designated As Hedges [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	0			0		0
Derivatives Designated As Hedges [Member] | Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	0			0		0
Derivatives Not Designated As Hedges [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	25			25		177
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	137			137		183
Derivatives Not Designated As Hedges [Member] | Embedded Derivative Financial Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	55			55		27
Derivatives Not Designated As Hedges [Member] | Deferred Compensation Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 17			$ 17		$ 31
Derivatives Not Designated As Hedges [Member] | Treasury Lock [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		$ 900
Wal-Mart Stores, Inc. [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Concentration Risk, Percentage						20.00%
Top Five Customers [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Concentration Risk, Percentage						43.00%
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Derivatives Designated As Hedges [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount						$ 80
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Derivatives Not Designated As Hedges [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount						3
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount						$ 3