FAIR VALUE MEASUREMENTS - Schedule of Fair Values of Financial Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Liabilities:
Fair Value, Long-term debt, including current portion	$ 2,281.3	$ 2,131.5
Carrying Value, Long-term debt, including current portion	2,905.8	2,823.9
Level 1
Liabilities:
Fair Value, Long-term debt, including current portion	0.0	0.0
Level 2
Liabilities:
Fair Value, Long-term debt, including current portion	2,281.3	2,131.5
Level 3
Liabilities:
Fair Value, Long-term debt, including current portion	$ 0.0	$ 0.0