FAIR VALUE MEASUREMENTS (Details 2) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Long-term Debt, Fair Value	$ 3,856.7	$ 3,979.9
Debt, Long-term and Short-term, Combined Amount	3,617.6	3,848.8
Fair Value, Inputs, Level 1
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Long-term Debt, Fair Value	0.0	0.0
Fair Value, Inputs, Level 2
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Long-term Debt, Fair Value	3,703.7	3,826.9
Fair Value, Inputs, Level 3
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Long-term Debt, Fair Value	$ 153.0	$ 153.0