FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Fair Value of Assets and Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	$ 77.0	$ 177.0
Derivative Asset	89.5	33.1
Total Asset	166.5	210.1
Derivative Liability	9.3	0.5
Total Liability	9.3	0.5
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	40.0	177.0
Derivative Asset	0.0	0.0
Total Asset	40.0	177.0
Derivative Liability	0.0	0.0
Total Liability	0.0	0.0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	37.0	0.0
Derivative Asset	0.0	1.5
Total Asset	37.0	1.5
Derivative Liability	0.0	0.0
Total Liability	0.0	0.0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents	0.0	0.0
Derivative Asset	89.5	31.6
Total Asset	89.5	31.6
Derivative Liability	9.3	0.5
Total Liability	$ 9.3	$ 0.5