Pension And Postretirement Benefits (Schedule Of Pension Plan Assets By Category) (Details) (USD $) In Millions	Jul. 31, 2011	Aug. 01, 2010	Aug. 02, 2009
Pension plan assets	$ 2,059	$ 1,767	$ 1,415
Level 1 [Member]
Pension plan assets	675	562
Level 1 [Member] | Short Term Investment [Member]
Pension plan assets	5	5
Level 1 [Member] | Equities [Member] | United States [Member]
Pension plan assets	396	308
Level 1 [Member] | Equities [Member] | Non-U.S. [Member]
Pension plan assets	267	245
Level 1 [Member] | Domestic Corporate Bonds [Member] | United States [Member]
Pension plan assets
Level 1 [Member] | Foreign Corporate Bonds [Member] | Non-U.S. [Member]
Pension plan assets
Level 1 [Member] | Domestic Government And Agency Bonds [Member] | United States [Member]
Pension plan assets
Level 1 [Member] | Foreign Government And Agency Bonds [Member] | Non-U.S. [Member]
Pension plan assets
Level 1 [Member] | Municipal Bonds [Member]
Pension plan assets
Level 1 [Member] | Commingled Funds [Member] | Equities Funds [Member]
Pension plan assets
Level 1 [Member] | Commingled Funds [Member] | Fixed Income Funds [Member]
Pension plan assets
Level 1 [Member] | Mortgage And Asset Backed Securities [Member]
Pension plan assets
Level 1 [Member] | Real Estate [Member]
Pension plan assets	7	4
Level 1 [Member] | Limited Partnerships [Member]
Pension plan assets
Level 1 [Member] | Hedge Funds [Member]
Pension plan assets
Level 1 [Member] | Guaranteed Insurance Contracts [Member]
Pension plan assets
Level 2 [Member]
Pension plan assets	1,350	1,142
Level 2 [Member] | Short Term Investment [Member]
Pension plan assets	60	55
Level 2 [Member] | Equities [Member] | United States [Member]
Pension plan assets
Level 2 [Member] | Equities [Member] | Non-U.S. [Member]
Pension plan assets
Level 2 [Member] | Domestic Corporate Bonds [Member] | United States [Member]
Pension plan assets	414	357
Level 2 [Member] | Foreign Corporate Bonds [Member] | Non-U.S. [Member]
Pension plan assets	88	89
Level 2 [Member] | Domestic Government And Agency Bonds [Member] | United States [Member]
Pension plan assets	9	21
Level 2 [Member] | Foreign Government And Agency Bonds [Member] | Non-U.S. [Member]
Pension plan assets	31	21
Level 2 [Member] | Municipal Bonds [Member]
Pension plan assets	42	17
Level 2 [Member] | Commingled Funds [Member] | Equities Funds [Member]
Pension plan assets	366	298
Level 2 [Member] | Commingled Funds [Member] | Fixed Income Funds [Member]
Pension plan assets	73	46
Level 2 [Member] | Mortgage And Asset Backed Securities [Member]
Pension plan assets	27	26
Level 2 [Member] | Real Estate [Member]
Pension plan assets	44	38
Level 2 [Member] | Limited Partnerships [Member]
Pension plan assets
Level 2 [Member] | Hedge Funds [Member]
Pension plan assets	196	174
Level 2 [Member] | Guaranteed Insurance Contracts [Member]
Pension plan assets
Level 3 [Member]
Pension plan assets	39	50	68
Level 3 [Member] | Short Term Investment [Member]
Pension plan assets
Level 3 [Member] | Equities [Member] | United States [Member]
Pension plan assets
Level 3 [Member] | Equities [Member] | Non-U.S. [Member]
Pension plan assets
Level 3 [Member] | Domestic Corporate Bonds [Member] | United States [Member]
Pension plan assets
Level 3 [Member] | Foreign Corporate Bonds [Member] | Non-U.S. [Member]
Pension plan assets
Level 3 [Member] | Domestic Government And Agency Bonds [Member] | United States [Member]
Pension plan assets
Level 3 [Member] | Foreign Government And Agency Bonds [Member] | Non-U.S. [Member]
Pension plan assets
Level 3 [Member] | Municipal Bonds [Member]
Pension plan assets
Level 3 [Member] | Commingled Funds [Member] | Equities Funds [Member]
Pension plan assets
Level 3 [Member] | Commingled Funds [Member] | Fixed Income Funds [Member]
Pension plan assets
Level 3 [Member] | Mortgage And Asset Backed Securities [Member]
Pension plan assets
Level 3 [Member] | Real Estate [Member]
Pension plan assets	19	18	32
Level 3 [Member] | Limited Partnerships [Member]
Pension plan assets	20	24	31
Level 3 [Member] | Hedge Funds [Member]
Pension plan assets
Level 3 [Member] | Guaranteed Insurance Contracts [Member]
Pension plan assets		8	5
Total Before Other Items [Member]
Pension plan assets	2,064	1,754
Short Term Investment [Member]
Pension plan assets	65	60
Equities [Member] | United States [Member]
Pension plan assets	396	308
Equities [Member] | Non-U.S. [Member]
Pension plan assets	267	245
Domestic Corporate Bonds [Member] | United States [Member]
Pension plan assets	414	357
Foreign Corporate Bonds [Member] | Non-U.S. [Member]
Pension plan assets	88	89
Domestic Government And Agency Bonds [Member] | United States [Member]
Pension plan assets	9	21
Foreign Government And Agency Bonds [Member] | Non-U.S. [Member]
Pension plan assets	31	21
Municipal Bonds [Member]
Pension plan assets	42	17
Commingled Funds [Member] | Equities Funds [Member]
Pension plan assets	366	298
Commingled Funds [Member] | Fixed Income Funds [Member]
Pension plan assets	73	46
Mortgage And Asset Backed Securities [Member]
Pension plan assets	27	26
Real Estate [Member]
Pension plan assets	70	60
Limited Partnerships [Member]
Pension plan assets	20	24
Hedge Funds [Member]
Pension plan assets	196	174
Guaranteed Insurance Contracts [Member]
Pension plan assets		8
Other Items To Reconcile To Fair Value Of Plan Assets [Member]
Pension plan assets	$ (5)	$ 13