Pension And Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 29, 2012	Jan. 30, 2011	Jan. 29, 2012	Jan. 30, 2011
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 13	$ 15	$ 27	$ 29
Interest cost	30	31	61	61
Expected return on plan assets	(44)	(45)	(89)	(89)
Recognized net actuarial loss	19	17	37	35
Net periodic benefit expense	18	18	36	36
Postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	1	2	2
Interest cost	5	5	9	9
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(1)	(1)	(1)	(1)
Recognized net actuarial loss	2	2	4	4
Net periodic benefit expense	7	7	14	14
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer			55
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	0		0
Foreign Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer			8
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	$ 6		$ 6