Fair Value Measurements (Fair Value Measurement Of Assets And Liabilities) (Details) (Measured On Recurring Basis [Member], USD $) In Millions, unless otherwise specified	Apr. 29, 2012		Jul. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	$ 24		$ 37
Total liabilities at fair value	207		287
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2		3
Total liabilities at fair value	113		99
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	22		34
Total liabilities at fair value	94		188
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
Interest Rate Contract [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	18	[1]	33	[1]
Interest Rate Contract [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[1]		[1]
Interest Rate Contract [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	18	[1]	33	[1]
Interest Rate Contract [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[1]		[1]
Foreign Exchange Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1	[2]	0	[2]
Total liabilities at fair value	2	[2]	9	[2]
Foreign Exchange Forward Contracts [Member] | 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]
Foreign Exchange Forward Contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	1	[2]	0	[2]
Total liabilities at fair value	2	[2]	9	[2]
Foreign Exchange Forward Contracts [Member] | 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]
Cross-Currency Swap Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3	[3]	1	[3]
Total liabilities at fair value	92	[3]	129	[3]
Cross-Currency Swap Contracts [Member] | Level 1 [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]
Cross-Currency Swap Contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	3	[3]	1	[3]
Total liabilities at fair value	92	[3]	129	[3]
Cross-Currency Swap Contracts [Member] | 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 liabilities at fair value		[4]	3	[4]
Deferred Compensation Derivative Contracts [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value		[4]		[4]
Deferred Compensation Derivative Contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value		[4]	3	[4]
Deferred Compensation Derivative Contracts [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value		[4]		[4]
Commodity Derivative Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[5]	3	[5]
Total liabilities at fair value	3	[5]	2	[5]
Commodity Derivative Contracts [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value	2	[5]	3	[5]
Total liabilities at fair value	3	[5]	2	[5]
Commodity Derivative Contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[5]		[5]
Total liabilities at fair value		[5]		[5]
Commodity Derivative Contracts [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value		[5]		[5]
Total liabilities at fair value		[5]		[5]
Deferred Compensation Obligation [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	110	[6]	144	[6]
Deferred Compensation Obligation [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	110	[6]	97	[6]
Deferred Compensation Obligation [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value	0	[6]	47	[6]
Deferred Compensation Obligation [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities at fair value		[6]		[6]

[1] Based on LIBOR swap rates.

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

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

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

[5] Based on quoted futures exchanges.

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