Pension And Postretirement Benefits (Schedule of Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets) (Details) (Pension Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	Jul. 28, 2013	Jul. 29, 2012
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation	$ 1,817	$ 2,739
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation	1,791	2,653
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets	$ 1,625	$ 2,114