Long-Term Debt (Details) - USD ($)
$ in Millions |
Oct. 31, 2015 |
Jan. 31, 2015 |
Nov. 01, 2014 |
| Debt Repurchase Provision, Debt Repurchase at a Percentage Price |
|
101.00%
|
|
|
| Current maturities of long-term debt |
|
$ 106
|
$ 28
|
$ 28
|
| Unamortized Debt Issuance Expense |
|
76
|
95
|
100
|
| Long-term Debt |
|
5,253
|
5,255
|
5,257
|
| Long-term debt, outstanding principal |
|
5,329
|
5,350
|
5,357
|
| Total long-term debt, excluding capital leases and note payable |
|
$ 5,147
|
5,227
|
5,229
|
| Senior Notes 5.65% Due 2020 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
5.65%
|
|
|
| Unamortized Debt Issuance Expense |
[1] |
$ 4
|
5
|
5
|
| Long-term Debt |
[1] |
396
|
395
|
395
|
| Long-term debt, outstanding principal |
[1] |
$ 400
|
400
|
400
|
| Senior Notes 5.75% Due 2018 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
5.75%
|
|
|
| Unamortized Debt Issuance Expense |
[1] |
$ 1
|
1
|
1
|
| Long-term Debt |
[1] |
299
|
299
|
299
|
| Long-term debt, outstanding principal |
[1] |
$ 300
|
300
|
300
|
| Senior Notes 6.375% Due 2036 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
6.375%
|
|
|
| Unamortized Debt Issuance Expense |
[1] |
$ 6
|
7
|
7
|
| Long-term Debt |
[1] |
394
|
393
|
393
|
| Long-term debt, outstanding principal |
[1] |
$ 400
|
400
|
400
|
| Senior Notes 8.125% due 2019 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
8.125%
|
|
|
| Unamortized Debt Issuance Expense |
|
$ 8
|
10
|
10
|
| Long-term Debt |
|
392
|
390
|
390
|
| Long-term debt, outstanding principal |
|
$ 400
|
400
|
400
|
| Notes 6.9% Due 2026 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
6.90%
|
|
|
| Long-term Debt |
|
$ 2
|
2
|
2
|
| Long-term debt, outstanding principal |
|
$ 2
|
2
|
2
|
| Debentures 7.125% Due 2023 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
7.125%
|
|
|
| Long-term Debt |
|
$ 10
|
10
|
10
|
| Long-term debt, outstanding principal |
|
$ 10
|
10
|
10
|
| Debentures 7.4% Due 2037 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
7.40%
|
|
|
| Unamortized Debt Issuance Expense |
|
$ 1
|
1
|
1
|
| Long-term Debt |
|
325
|
325
|
325
|
| Long-term debt, outstanding principal |
|
$ 326
|
326
|
326
|
| Notes 7.625% Due 2097 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
7.625%
|
|
|
| Long-term Debt |
|
$ 500
|
500
|
500
|
| Long-term debt, outstanding principal |
|
$ 500
|
500
|
500
|
| Debentures 7.65% due 2016 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
7.65%
|
|
|
| Long-term Debt |
|
$ 78
|
78
|
78
|
| Long-term debt, outstanding principal |
|
$ 78
|
78
|
78
|
| Debentures 7.95% due 2017 [Member] |
|
|
|
|
| Debt Instrument, Interest Rate, Stated Percentage |
|
7.95%
|
|
|
| Long-term Debt |
|
$ 220
|
220
|
220
|
| Long-term debt, outstanding principal |
|
220
|
220
|
220
|
| 2013 Term Loan Facility [Member] |
|
|
|
|
| Unamortized Debt Issuance Expense |
|
45
|
58
|
62
|
| Long-term Debt |
|
2,154
|
2,158
|
2,160
|
| Long-term debt, outstanding principal |
|
2,199
|
2,216
|
2,222
|
| 2014 Term Loan [Member] |
|
|
|
|
| Unamortized Debt Issuance Expense |
|
11
|
13
|
14
|
| Long-term Debt |
|
483
|
485
|
485
|
| Long-term debt, outstanding principal |
|
$ 494
|
$ 498
|
$ 499
|
|
|