Postretirement Health Care and Life Insurance Benefits (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
2016 reduction in service cost and interest cost	$ 36
Other Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	3.14%	3.55%	4.50%
2016 reduction in service cost and interest cost	$ 2
Previously Reported | Other Postretirement Benefit Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Discount rate	4.15%