Retirement Benefit Plans (Accumulated Other Comprehensive (Loss)/Income) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Jan. 31, 2015
Feb. 01, 2014
Jan. 31, 2013
Supplemental Employee Retirement Plan [Member]      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Net loss/(gain) $ 110 $ 127  
Prior service cost/(credit) (4) (6)  
Defined Benefit Plan, Accumulated Other Comprehensive Income, before Tax, Total 106 121  
Defined Benefit Plan, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year 13    
Pension Plan [Member]      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Net loss/(gain) 1,331 898  
Prior service cost/(credit) 65 53  
Defined Benefit Plan, Accumulated Other Comprehensive Income, before Tax, Total 1,396 951  
Defined Benefit Plan, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year 111    
Other Postretirement Benefit Plan, Defined Benefit [Member]      
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]      
Net loss/(gain) (8)   (6)
Prior service cost/(credit) (7)   (15)
Defined Benefit Plan, Accumulated Other Comprehensive Income, before Tax, Total (15) [1]   (21)
Defined Benefit Plan, Amounts that Will be Amortized from Accumulated Other Comprehensive Income (Loss) in Next Fiscal Year $ (1) $ (7)  
[1] In 2015, approximately $(1) million of net actuarial loss/(gain) and $(7) million of prior service cost/(credit) for the postretirement plan are expected to be amortized from Accumulated other comprehensive income/(loss) into net periodic postretirement benefit (income) included in SG&A in the Consolidated Statement of Operations.