PENSION AND POST-RETIREMENT BENEFITS - Fair Value of Asset Categories (Details) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018 |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | $ 462.4 | $ 432.4 |
Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 377.4 | 360.6 |
Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 179 | 159.7 |
Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 198.4 | 200.9 |
Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Investments measured at Net Asset Value | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 85 | 71.8 |
U.S. Small/Mid Cap Equity | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 7 |
U.S. Small/Mid Cap Equity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 7 |
U.S. Small/Mid Cap Equity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
U.S. Small/Mid Cap Equity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Corporate Bonds | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 10.8 | 10.6 |
Mutual Funds, Corporate Bonds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 10.8 | 10.6 |
Mutual Funds, Corporate Bonds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Corporate Bonds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Government Bonds | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 15.8 | 13.4 |
Mutual Funds, Government Bonds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 15.8 | 13.4 |
Mutual Funds, Government Bonds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Government Bonds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, U.S. Large Cap Equiy | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0.2 | 0.2 |
Mutual Funds, U.S. Large Cap Equiy | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0.2 | 0.2 |
Mutual Funds, U.S. Large Cap Equiy | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, U.S. Large Cap Equiy | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, International Equities | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 16.3 | 9.4 |
Mutual Funds, International Equities | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 16.3 | 9.4 |
Mutual Funds, International Equities | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, International Equities | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Emerging Markets International Equity | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 5.9 | 5.3 |
Mutual Funds, Emerging Markets International Equity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 5.9 | 5.3 |
Mutual Funds, Emerging Markets International Equity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Emerging Markets International Equity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Cash and Cash Equivalents | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 1.6 | 2.2 |
Mutual Funds, Cash and Cash Equivalents | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 1.6 | 2.2 |
Mutual Funds, Cash and Cash Equivalents | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Cash and Cash Equivalents | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Other | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 2 | 1.8 |
Mutual Funds, Other | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 2 | 1.8 |
Mutual Funds, Other | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Mutual Funds, Other | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Fixed Income Securities, Corporate Bonds | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Fixed Income Securities, Corporate Bonds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Fixed Income Securities, Corporate Bonds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Fixed Income Securities, Corporate Bonds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Fixed Income Securities, Government Bonds | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 72.2 | 70 |
Fixed Income Securities, Government Bonds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Fixed Income Securities, Government Bonds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 72.2 | 70 |
Fixed Income Securities, Government Bonds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Corporate Bonds | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 33.6 | 40.7 |
Common and Collective Funds, Corporate Bonds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 19.4 | 19.6 |
Common and Collective Funds, Corporate Bonds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 14.2 | 21.1 |
Common and Collective Funds, Corporate Bonds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Government Bonds | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 38.9 | 43 |
Common and Collective Funds, Government Bonds | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 9.1 | 6.6 |
Common and Collective Funds, Government Bonds | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 29.8 | 36.4 |
Common and Collective Funds, Government Bonds | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, U.S. Large Cap Equity | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 55.5 | 54.5 |
Common and Collective Funds, U.S. Large Cap Equity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 48.7 | 38.8 |
Common and Collective Funds, U.S. Large Cap Equity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 6.8 | 15.7 |
Common and Collective Funds, U.S. Large Cap Equity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, U.S. Small/Mid Cap Equity | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 18.2 | 6.9 |
Common and Collective Funds, U.S. Small/Mid Cap Equity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 18.2 | 6.9 |
Common and Collective Funds, U.S. Small/Mid Cap Equity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, U.S. Small/Mid Cap Equity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, International Equities | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 70.8 | 58.4 |
Common and Collective Funds, International Equities | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 3.4 | 5.5 |
Common and Collective Funds, International Equities | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 67.4 | 52.9 |
Common and Collective Funds, International Equities | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Emerging Markets International Equity | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 18.1 | 14.9 |
Common and Collective Funds, Emerging Markets International Equity | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 13 | 8.5 |
Common and Collective Funds, Emerging Markets International Equity | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 5.1 | 6.4 |
Common and Collective Funds, Emerging Markets International Equity | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Cash and Cash Equivalents | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 1.7 | 1.7 |
Common and Collective Funds, Cash and Cash Equivalents | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 1.7 | 1.7 |
Common and Collective Funds, Cash and Cash Equivalents | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Cash and Cash Equivalents | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Other | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 2.9 | (1.6) |
Common and Collective Funds, Other | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds, Other | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 2.9 | (1.6) |
Common and Collective Funds, Other | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Cash and Cash Equivalents | Total | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 12.9 | 22.2 |
Cash and Cash Equivalents | Level 1 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 12.9 | 22.2 |
Cash and Cash Equivalents | Level 2 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Cash and Cash Equivalents | Level 3 | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 0 | 0 |
Common and Collective Funds | Investments measured at Net Asset Value | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | 52.4 | 36.3 |
Hedge Funds | Investments measured at Net Asset Value | | |
Defined Benefit Plan Disclosure [Line Items] | | |
Fair value of plan assets | $ 32.6 | $ 35.5 |