Retirement Benefit Plans (Defined Contribution Plans) (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Oct. 29, 2011
Oct. 30, 2010
Oct. 29, 2011
Oct. 30, 2010
Retirement Benefit Plans        
Defined contribution plan, total expense $ 16 $ 13 $ 48 $ 39