Retirement Benefit Plans (Net Periodic Expense) (Details) - USD ($)
$ in Millions |
3 Months Ended |
|
Apr. 30, 2016 |
May. 02, 2015 |
Jan. 30, 2016 |
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
| Net periodic benefit expense/(income) |
$ 2
|
$ (19)
|
|
| Primary Pension Plan |
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
| Service cost |
14
|
17
|
|
| Interest cost |
38
|
49
|
|
| Expected return on plan assets |
(54)
|
(89)
|
|
| Amortization of prior service cost/(credit) |
2
|
2
|
|
| Net periodic benefit expense/(income) |
0
|
(21)
|
|
| Supplemental Pension Plans |
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
| Interest cost |
2
|
2
|
|
| Net periodic benefit expense/(income) |
2
|
2
|
|
| Primary and Supplemental Pension Plans Total |
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
| Service cost |
14
|
17
|
|
| Interest cost |
40
|
51
|
|
| Expected return on plan assets |
(54)
|
(89)
|
|
| Amortization of prior service cost/(credit) |
2
|
2
|
|
| Net periodic benefit expense/(income) |
2
|
(19)
|
|
| Postretirement Health and Welfare Plan |
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
| Net periodic benefit expense/(income) |
(4)
|
$ (2)
|
|
| Defined Benefit Plan, Accumulated Benefit Obligation |
$ 1
|
|
$ 8
|