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SHAREHOLDERS' EQUITY (Details) - USD ($) shares in Millions, $ in Millions | 3 Months Ended | 5 Months Ended | 9 Months Ended |
--- | --- | --- | --- | ---
Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2017 | Sep. 30, 2018 | Sep. 30, 2018 | Sep. 30, 2017 | Apr. 26, 2018
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Common stock repurchased and retired |  |  |  |  |  |  |  | $ 16.8 | $ 0.0 |
Stock options exercised |  |  |  |  |  |  |  | 0.2 | 1.0 |
Total value of stock options exercised |  |  |  |  |  |  |  | $ 3.2 | $ 18.5 |
Foreign Currency Translation Adjustment [Roll Forward] |  |  |  |  |  |  |  |  |  |
Beginning Balance |  |  | $ 7.6 |  |  | $ (24.1) |  | 7.6 | (24.1) |
Unrealized Gains (Losses), before Reclassification Adjustments and Tax | $ (2.0) | $ (26.1) | 12.4 | $ 16.0 | $ 28.1 | 8.3 |  |  |  |
Reclassification adjustments into income (gains) losses | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |  |  |  |
Tax (Provision) Benefit | 0.0 | 0.0 | 0.0 | (6.2) | (12.2) | (2.3) |  |  |  |
Net Change in Foreign Currency Translation Adjustment |  |  |  |  |  |  |  | (15.7) | 31.7 |
Income Tax Reclassification Adjustment, Foreign Currency Translation |  |  |  |  |  |  |  | 15.3 |  |
Ending Balance | 7.2 |  |  | 7.6 |  |  | $ 7.2 | 7.2 | 7.6 |
Unrealized Gains (Losses) on Derivative Contracts (net of taxes) [Roll Forward] |  |  |  |  |  |  |  |  |  |
Beginning Balance |  |  | 11.1 |  |  | 12.8 |  | 11.1 | 12.8 |
Unrealized Gains (Losses) on Derivatives Arising During Period, before Tax | (2.6) | (0.4) | 2.1 | 3.2 | (3.7) | (3.1) |  |  |  |
Reclassification adjustments into income (gains) losses | (2.2) | (2.7) | (2.3) | (1.2) | (2.3) | (0.1) |  |  |  |
Derivatives Qualifying as Hedges, Tax (Provision) Benefit | 1.2 | 0.7 | 0.1 | (0.7) | 2.3 | 1.2 |  |  |  |
Net Change in Derivatives Qualifying as Hedges, Net of Tax | (3.6) |  |  | 1.3 |  |  |  | (6.1) | (4.4) |
Income Tax Reclassification Adjustment, Derivative Contracts |  |  |  |  |  |  |  | 2.4 |  |
Ending Balance | 7.4 |  |  | 8.4 |  |  | 7.4 | 7.4 | 8.4 |
Pension and Postretirement Benefits (net of taxes) [Roll Forward] |  |  |  |  |  |  |  |  |  |
Beginning Balance |  |  | (503.3) |  |  | (498.7) |  | (503.3) | (498.7) |
Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments and Tax | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 |  |  |  |
Reclassification adjustments into income (gains) losses | 9.2 | 9.1 | 9.4 | 6.8 | 6.8 | 6.6 |  |  |  |
Deferred Tax (Provision) Benefit on Pension and Other Postretirement Benefit Plans | (1.7) | (1.0) | (4.0) | (2.5) | (2.3) | (2.7) |  |  |  |
Net Change in Pension and Other Postretirement Benefit Plans, Net of Tax |  |  |  |  |  |  |  | 21.0 | 12.7 |
Income Tax Reclassification Adjustment, Pension and Postretirement Benefits |  |  |  |  |  |  |  | (103.6) |  |
Ending Balance | (585.9) |  |  | (486.0) |  |  | (585.9) | (585.9) | (486.0) |
Accumulated Other Comprehensive Loss [Roll Forward] |  |  |  |  |  |  |  |  |  |
Beginning Balance |  |  | (484.6) |  |  | (510.0) |  | (484.6) | (510.0) |
Unrealized gains (losses) | (4.6) | (26.5) | 14.5 | 19.2 | 24.4 | 5.2 |  |  |  |
Reclassification adjustments into income (gains) losses | 7.0 | 6.4 | 7.1 | 5.6 | 4.5 | 6.5 |  |  |  |
Tax (provision) benefit | (0.5) | $ (0.3) | $ (3.9) | (9.4) | $ (12.2) | $ (3.8) |  |  |  |
Other Comprehensive Income (Loss), Net of Tax |  |  |  |  |  |  |  | (0.8) | 40.0 |
Income tax reclassification adjustment |  |  |  |  |  |  |  | (85.9) |  |
Ending Balance | (571.3) |  |  | $ (470.0) |  |  | $ (571.3) | $ (571.3) | $ (470.0) |
2018 Share Repurchase Program | Common Stock |  |  |  |  |  |  |  |  |  |
Equity, Class of Treasury Stock [Line Items] |  |  |  |  |  |  |  |  |  |
Authorized share repurchase program (in dollars) |  |  |  |  |  |  |  |  |  | $ 500.0
Stock Repurchased and Retired During Period, Shares |  |  |  |  |  |  | 0.5 | 0.5 |  |
Common stock repurchased and retired |  |  |  |  |  |  | $ 16.8 | $ 16.8 |  |
Stock Repurchase Program, Remaining Authorized Repurchase Amount | $ 483.2 |  |  |  |  |  | $ 483.2 | $ 483.2 |  |

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