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PENSION AND POST-RETIREMENT PLANS - AMOUNTS INCLUDED IN FINANCIAL STATEMENTS (Details) - USD ($) $ in Millions | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Employee benefit plans |  |  |
Current liabilities | $ (2.7) | $ (3.1) |
Non-current liabilities, net | (82.0) | (73.4) |
Pension Benefits |  |  |
Employee benefit plans |  |  |
Projected benefit obligations | 263.1 | 239.9 | $ 217.4
Fair value of plan assets at end of year | 212.8 | 194.8 | 162.2
Pension Benefits | Qualified Plan |  |  |
Employee benefit plans |  |  |
Non-current assets | 1.0 | 1.0 |
Non-current liabilities, net | (51.3) | (46.1) |
Total | (50.3) | (45.1) |
Net loss, net of taxes | (64.2) | (56.2) |
Prior service credit, net of taxes | 2.5 | 4.3 |
Total | (61.7) | (51.9) |
Projected benefit obligations | 261.4 | 238.3 |
Accumulated benefit obligation | 260.9 | 237.9 |
Fair value of plan assets at end of year | 210.0 | 192.2 |
Pension Benefits | Nonqualified Plan |  |  |
Employee benefit plans |  |  |
Current liabilities | (1.7) | (2.1) |
Non-current liabilities, net | (2.6) | (2.3) |
Total | (4.3) | (4.4) |
Net loss, net of taxes | (0.8) | (0.6) |
Prior service credit, net of taxes | 0.1 | 0.2 |
Total | (0.7) | (0.4) |
Post-retirement Benefits |  |  |
Employee benefit plans |  |  |
Projected benefit obligations | $ 29.1 | 26.0 | $ 22.2
Amortization period of unrecognized gains and losses | 5 years |  |
Post-retirement Benefits | Qualified Plan |  |  |
Employee benefit plans |  |  |
Current liabilities | $ (1.0) | (1.0) |
Non-current liabilities, net | (28.1) | (25.0) |
Total | (29.1) | (26.0) |
Net loss, net of taxes | (4.4) | (2.8) |
Prior service credit, net of taxes | 16.6 | 19.1 |
Total | $ 12.2 | $ 16.3 |

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