Pension And Postretirement Benefits Pension And Postretirement Benefits (Schedule Of Effect Of One-Percentage-Point Change In Assumed Health Care Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Jul. 29, 2012
Pension and Postretirement Benefits [Abstract]
Effect on service and interest cost, increase	$ 1
Effect on the 2012 accumulated benefit obligation, increase	35
Effect on service and interest cost, decrease	0
Effect on the 2012 accumulated benefit obligation, decrease	$ (10)