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Postretirement Health Care and Life Insurance Benefits (Narrative) (Details) - Other Postretirement Benefits Plan [Member] - USD ($)
$ in Millions
12 Months Ended
Feb. 03, 2018
Jan. 28, 2017
Jan. 30, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Defined Benefit Plan, Expected Amortization of Gain (Loss), Next Fiscal Year $ 6    
Discount rate 3.17% 3.14% 3.55%