Pension And Postretirement Benefits (Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Costs) (Details) (Other Postretirement Benefit Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 28, 2013
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	$ 1
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	(1)
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	21
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	$ (19)