Retirement Benefit Plans (Net Periodic Expense) (Details) - USD ($)
$ in Millions |
3 Months Ended |
9 Months Ended |
|
Oct. 29, 2016 |
Oct. 31, 2015 |
Oct. 29, 2016 |
Oct. 31, 2015 |
Jan. 30, 2016 |
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
|
|
|
|
| Net periodic benefit expense/(income) |
$ 1
|
$ (17)
|
[1] |
$ 5
|
$ (52)
|
[1] |
|
| Other Postretirement Benefit Plan [Member] |
|
|
|
|
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
|
|
|
|
| Net periodic benefit expense/(income) |
(6)
|
(2)
|
|
(14)
|
(6)
|
|
|
| Defined Benefit Plan, Accumulated Benefit Obligation |
1
|
|
|
1
|
|
|
$ 8
|
| Primary Pension Plan |
|
|
|
|
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
|
|
|
|
| Service cost |
14
|
17
|
|
41
|
52
|
|
|
| Interest cost |
38
|
49
|
|
114
|
147
|
|
|
| Other cost |
0
|
2
|
|
0
|
5
|
|
|
| Expected return on plan assets |
(54)
|
(89)
|
|
(161)
|
(267)
|
|
|
| Amortization of prior service cost/(credit) |
2
|
2
|
|
6
|
6
|
|
|
| Net periodic benefit expense/(income) |
0
|
(19)
|
|
0
|
(57)
|
|
|
| Supplemental Pension Plans |
|
|
|
|
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
|
|
|
|
| Interest cost |
1
|
2
|
|
5
|
5
|
|
|
| Net periodic benefit expense/(income) |
1
|
2
|
|
5
|
5
|
|
|
| Primary and Supplemental Pension Plans Total |
|
|
|
|
|
|
|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
|
|
|
|
|
|
|
| Service cost |
14
|
17
|
|
41
|
52
|
|
|
| Interest cost |
39
|
51
|
|
119
|
152
|
|
|
| Other cost |
0
|
2
|
|
0
|
5
|
|
|
| Expected return on plan assets |
(54)
|
(89)
|
|
(161)
|
(267)
|
|
|
| Amortization of prior service cost/(credit) |
2
|
2
|
|
6
|
6
|
|
|
| Net periodic benefit expense/(income) |
$ 1
|
$ (17)
|
|
$ 5
|
$ (52)
|
|
|
|
|