Pension And Postretirement Benefits (Schedule of amounts recognized in the Consolidated Balance Sheets) (Details) (USD $) In Millions, unless otherwise specified	Jul. 28, 2013	Jul. 29, 2012
Disposal Group, Including Discontinued Operation, Pension Plan Benefit Obligation	$ (11)
Pension Plans, Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(13)	(12)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(190)	(618)
Disposal Group, Including Discontinued Operation, Pension Plan Benefit Obligation	(11)	0
Defined Benefit Plan, Amounts Recognized in Balance Sheet	(214)	(630)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net (Gains) Losses, before Tax	1,068	1,486
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	(2)	(3)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	1,066	1,483
Other Postretirement Benefit Plans, Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(29)	(27)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(361)	(386)
Defined Benefit Plan, Amounts Recognized in Balance Sheet	(390)	(413)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net (Gains) Losses, before Tax	104	133
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	(6)	(8)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	$ 98	$ 125