Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 26, 2020	Jan. 27, 2019	Jan. 26, 2020	Jan. 27, 2019	Jul. 28, 2019
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	$ 6	$ 0	$ 9	$ (4)
Other Current Assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Margin Deposit Assets					$ 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	3	$ 0	$ 3	$ 0
Derivatives Designated As Hedges [Member] | Foreign Exchange Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	94		94		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	53		53		177
Derivatives Not Designated As Hedges [Member] | Currency Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	0		0		0
Derivatives Not Designated As Hedges [Member] | Commodity Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	136		136		183
Derivatives Not Designated As Hedges [Member] | Embedded Derivative Financial Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	76		76		27
Derivatives Not Designated As Hedges [Member] | Deferred Compensation Derivative Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	31		31		$ 31
Derivatives Not Designated As Hedges [Member] | Treasury Lock [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	$ 900		$ 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