Income Taxes - Reconciliation of Total Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Jul. 31, 2016 |
Oct. 31, 2016 |
Oct. 31, 2015 |
Oct. 31, 2014 |
|
| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | ||||
| Beginning balance | $ 82.5 | $ 85.5 | $ 87.6 | |
| Additions for tax positions related to the current year | 0.0 | 2.1 | 1.4 | |
| Reductions for tax positions related to the current year | 0.0 | 0.0 | 0.0 | |
| Additions for tax positions related to prior years | 0.0 | 0.1 | 0.0 | |
| Reductions for tax positions related to prior years | (3.2) | 0.0 | 0.0 | |
| Reductions for lapse of statute of limitations | $ (19.0) | (21.9) | (5.2) | (3.2) |
| Settlements | (0.2) | 0.0 | (0.3) | |
| Ending Balance | $ 57.2 | $ 82.5 | $ 85.5 | |