|
Financial Instruments - Reconciliation of the Change in Level 3 Items (Details) (USD $)
In Millions, unless otherwise specified
|
12 Months Ended |
|
Jan. 31, 2014
|
Jan. 31, 2013
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
| Beginning Balance |
$ 32.4 |
$ 28.7 |
| Purchases |
4.4 |
9.0 |
| Settlements |
(4.0) |
(8.5) |
| Net realized losses |
(0.2) |
|
| Total unrealized gains (losses) |
(3.3) |
3.2 |
| Ending Balance |
29.3 |
32.4 |
|
Derivative Contracts
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
| Beginning Balance |
10.7 |
6.2 |
| Purchases |
1.3 |
2.0 |
| Settlements |
0 |
(1.3) |
| Net realized losses |
0 |
|
| Total unrealized gains (losses) |
(2.9) |
3.8 |
| Ending Balance |
9.1 |
10.7 |
|
Convertible Debt Securities
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
| Beginning Balance |
17.5 |
18.3 |
| Purchases |
3.1 |
7.0 |
| Settlements |
0 |
(7.2) |
| Net realized losses |
0 |
|
| Total unrealized gains (losses) |
(0.4) |
(0.6) |
| Ending Balance |
20.2 |
17.5 |
|
Taxable Auction-Rate Securities
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
| Beginning Balance |
4.2 |
4.2 |
| Purchases |
0 |
0 |
| Settlements |
(4.0) |
0 |
| Net realized losses |
(0.2) |
|
| Total unrealized gains (losses) |
0 |
0 |
| Ending Balance |
$ 0 |
$ 4.2 |