Benefit Plans (Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 27, 2012	Oct. 29, 2011	Oct. 27, 2012	Oct. 29, 2011
Pension Contributions				$ 225
Estimated contributions to the Pension Plan in the current fiscal year	150		150
Pension Plan [Member]
Service cost	30	25	88	76
Interest cost	40	40	118	120
Expected return on assets	(64)	(61)	(190)	(185)
Amortization of net actuarial (gain) loss	35	22	106	66
Amortization of prior service credit	(1)	(1)	(1)	(1)
Total net periodic benefit cost	40	25	121	76
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Service cost	1	1	4	4
Interest cost	9	9	26	27
Amortization of net actuarial (gain) loss	4	2	13	6
Amortization of prior service credit	0	0	0	(1)
Total net periodic benefit cost	14	12	43	36
Amount Recognized In Net Periodic Postretirement Benefit Cost [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Service cost	0	0	0	0
Interest cost	3	3	9	10
Amortization of net actuarial (gain) loss	(1)	(1)	(3)	(4)
Amortization of prior service credit	0	0	0	0
Total net periodic benefit cost	$ 2	$ 2	$ 6	$ 6