Annual report pursuant to Section 13 and 15(d)

Postretirement Health Care and Life Insurance Benefits (Assumed Health Care Cost Trend Rates) (Details)

v2.4.1.9
Postretirement Health Care and Life Insurance Benefits (Assumed Health Care Cost Trend Rates) (Details)
12 Months Ended
Jan. 31, 2015
Feb. 01, 2014
Rates to which is the cost trend rate is assumed to decline (the ultimate trend rate) 5.00%us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate 5.00%us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate
Year that the rate reaches the ultimate trend rate 2025 2025
Minimum [Member]    
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year 7.27%us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
7.27%us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Maximum [Member]    
Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year 8.90%us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
9.20%us-gaap_DefinedBenefitPlanHealthCareCostTrendRateAssumedForNextFiscalYear
/ us-gaap_RangeAxis
= us-gaap_MaximumMember