Retirement Benefit Plans Retirement Benefit Plans (Accumulated Benefit Obligation) (Details) (USD $)
In Millions, unless otherwise specified
Jan. 31, 2015
Feb. 01, 2014
Jan. 27, 2012
Pension Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Accumulated benefit obligation $ 4,900 $ 4,200  
Fair value of plan assets 5,474 5,140 5,035
Supplemental Employee Retirement Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Accumulated benefit obligation 166 200  
Fair value of plan assets $ 0 $ 0 $ 0