Retirement Benefit 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
Net periodic benefit expense / (income) $ 31 $ 64 $ 88 $ 191
Pension Plans [Member]
       
Service cost 23 22 68 67
Interest cost 65 65 195 196
Expected return on plan assets (97) (87) (290) (263)
Net amortization 40 64 115 191
Net periodic benefit expense / (income) 31 64 88 191
Benefits Plan Primary Plan [Member]
       
Service cost 22 22 66 66
Interest cost 62 62 186 186
Expected return on plan assets (97) (87) (290) (263)
Net amortization 35 59 103 177
Net periodic benefit expense / (income) 22 56 65 166
Benefits Supplemental Plan [Member]
       
Service cost 1   2 1
Interest cost 3 3 9 10
Net amortization 5 5 12 14
Net periodic benefit expense / (income) 9 8 23 25
Postretirement Health and Welfare Plan [Member]
       
Net amortization (6) (6) (19) (18)
Net periodic benefit expense / (income) $ (6) $ (6) $ (19) $ (18)