Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jan. 26, 2020	Aug. 02, 2020	Jul. 28, 2019	Jul. 29, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months		$ (2)
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(8)	$ (3)	$ 24
Other Current Assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Margin Deposit Assets		8	7
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		0	0
Treasury Lock [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		0	0
Treasury Lock [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 3	$ 3	0	$ 18
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
Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Contracts Mature Within, Months		18 months
Derivatives Designated As Hedges [Member] | Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		$ 0	0
Derivatives Designated As Hedges [Member] | Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		164	146
Derivatives Not Designated As Hedges [Member] | Treasury Lock [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 900
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		137	183
Derivatives Not Designated As Hedges [Member] | Embedded Derivative Financial Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		34	27
Derivatives Not Designated As Hedges [Member] | Deferred Compensation Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		22	31
Derivatives Not Designated As Hedges [Member] | Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount		$ 19	$ 177
Wal-Mart Stores, Inc. [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Entity Wide Revenue, Major Customer, Percentage Of Net Sales		21.00%	20.00%	22.00%
Top Five Customers [Member] | Customer Concentration Risk [Member] | Revenue Benchmark [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Entity Wide Revenue, Major Customer, Percentage Of Net Sales		44.00%
Discontinued Operations, Held-for-sale or Disposed of by Sale [Member] | Derivatives Designated As Hedges [Member] | Foreign Exchange Forward [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] | Commodity Derivative Contracts [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] | Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount			$ 3