Pension And Postretirement Benefits Pension And Postretirement Benefits (Schedule Of Changes In Fair Value Of Level 3 Investments) (Details) - Pension Plan, Defined Benefit [Member] - USD ($) $ in Millions	12 Months Ended
	Jul. 28, 2019	Jul. 29, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	$ 2,154	$ 2,183
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	162	137
Defined Benefit Plan, Plan Assets, Amount	2,153	2,154
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	10
Defined Benefit Plan, Plan Assets, Amount	9	10
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	34
Defined Benefit Plan, Plan Assets, Amount	32	34
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	40	45
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	1	4
Defined Benefit Plan, Purchases	0	0
Defined Benefit Plan, Sales	5	9
Defined Benefit Plan, Settlements	0	0
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Assets Transferred into (out of) Level 3	0	0
Defined Benefit Plan, Plan Assets, Amount	36	40
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	6	7
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	1	2
Defined Benefit Plan, Purchases	0	0
Defined Benefit Plan, Sales	3	3
Defined Benefit Plan, Settlements	0	0
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Assets Transferred into (out of) Level 3	0	0
Defined Benefit Plan, Plan Assets, Amount	4	6
Fair Value, Inputs, Level 3 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	34	38
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss)	0	2
Defined Benefit Plan, Purchases	0	0
Defined Benefit Plan, Sales	2	6
Defined Benefit Plan, Settlements	0	0
Defined Benefit Plan, Plan Assets Level 3 Reconciliation, Increase (Decrease) for Assets Transferred into (out of) Level 3	0	0
Defined Benefit Plan, Plan Assets, Amount	$ 32	$ 34