Postretirement Health Care and Life Insurance Benefits (Weighted Average Assumptions Used To Determine Net Periodic Costs For Postretirement Plans) (Details)	12 Months Ended
Jan. 28, 2017	Jan. 30, 2016	Jan. 31, 2015
Other Postretirement Benefit Plan [Member]
Discount rate	3.14%	3.55%	4.50%

The interest rate used to adjust for the time value of money.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration