INCOME TAXES - Effective income tax rate on earnings (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|---|
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Effect of: | ||||||
| Effective income tax rate (as a percent) | (27.90%) | |||||
| Tax contingencies and other tax liabilities | $ 18.1 | $ 18.1 | $ 15.3 | |||
| Net deferred tax assets | 14.8 | 14.8 | $ 20.7 | |||
| Income tax benefit | $ (11.1) | $ 17.6 | $ (13.2) | $ 136.4 | ||
| Forecast | ||||||
| Effect of: | ||||||
| Effective income tax rate (as a percent) | (3.40%) | |||||