Fair Value Measurements (Fair Value Measurement Of Assets And Liabilities) (Details) (Measured On Recurring Basis [Member], USD $) In Millions, unless otherwise specified	Jan. 27, 2013		Jul. 29, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 25		$ 45
Total liabilities at fair value	207		192
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3		5
Total liabilities at fair value	124		111
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	22		40
Total liabilities at fair value	83		81
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value
Total liabilities at fair value
Foreign Exchange Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1	[1]	2	[1]
Total liabilities at fair value	1	[1]		[1]
Foreign Exchange Forward Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[1]		[1]
Total liabilities at fair value		[1]		[1]
Foreign Exchange Forward Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1	[1]	2	[1]
Total liabilities at fair value	1	[1]		[1]
Foreign Exchange Forward Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[1]		[1]
Total liabilities at fair value		[1]		[1]
Cross-Currency Swap Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[2]	19	[2]
Total liabilities at fair value	80	[2]	79	[2]
Cross-Currency Swap Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[2]		[2]
Total liabilities at fair value		[2]		[2]
Cross-Currency Swap Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[2]	19	[2]
Total liabilities at fair value	80	[2]	79	[2]
Cross-Currency Swap Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[2]		[2]
Total liabilities at fair value		[2]		[2]
Commodity Derivative Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	5	[3]	8	[3]
Total liabilities at fair value	3	[3]	4	[3]
Commodity Derivative Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3	[3]	5	[3]
Total liabilities at fair value	1	[3]	2	[3]
Commodity Derivative Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[3]	3	[3]
Total liabilities at fair value	2	[3]	2	[3]
Commodity Derivative Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[3]		[3]
Total liabilities at fair value		[3]		[3]
Deferred Compensation Derivative Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[4]	1	[4]
Deferred Compensation Derivative Contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[4]		[4]
Deferred Compensation Derivative Contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[4]	1	[4]
Deferred Compensation Derivative Contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[4]		[4]
Deferred Compensation Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	123	[5]	109	[5]
Deferred Compensation Obligation [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	123	[5]	109	[5]
Deferred Compensation Obligation [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value		[5]		[5]
Deferred Compensation Obligation [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value		[5]		[5]
Fair Value Hedging [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	6	[6]	13	[6]
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[6]		[6]
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	6	[6]	13	[6]
Fair Value Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[6]		[6]
Cash Flow Hedging [Member] | Interest Rate Swap [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	9	[6]	2	[6]
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[6]		[6]
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	9	[6]	2	[6]
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[6]		[6]

[1] Based on observable market transactions of spot currency rates and forward rates.

[2] Based on observable local benchmarks for currency and interest rates.

[3] Based on quoted futures exchanges and on observable prices of futures and options transactions in the marketplace.

[4] Based on LIBOR and equity index swap rates.

[5] Based on the fair value of the participants’ investments.

[6] Based on LIBOR swap rates.