DERIVATIVE FINANCIAL INSTRUMENTS (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Derivatives, Fair Value [Line Items]
Liability derivatives	$ 10.8	$ 10.2	$ 16.2
Asset derivatives	8.7	15.9	11.7
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	10.8	10.2	13.8
Asset derivatives	0	7.5	1.8
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	0	0	1.8
Designated as Hedging Instrument [Member] | Interest Rate Contract Loss [Member] | Long-term Debt [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	9.5	10.2	12.0
Designated as Hedging Instrument [Member] | Commodity Contracts Gains [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	(3.1)	0	(3.6)
Designated as Hedging Instrument [Member] | Commodity Contracts Gains [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	0	9.6	0
Designated as Hedging Instrument [Member] | Commodity Contracts Losses [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	4.4	0	5.4
Designated as Hedging Instrument [Member] | Commodity Contracts Losses [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	0	(2.1)	0
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	0	0	2.4
Asset derivatives	8.7	8.4	9.9
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	10.8	11.9	11.0
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	0	0	0
Not Designated as Hedging Instrument [Member] | Interest Rate Contract Loss [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	(3.1)	(3.6)	(1.1)
Not Designated as Hedging Instrument [Member] | Interest Rate Contract Loss [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	0	0	0
Not Designated as Hedging Instrument [Member] | Commodity Contracts Gains [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	0	0	0
Not Designated as Hedging Instrument [Member] | Commodity Contracts Gains [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	1.0	0.1	0
Not Designated as Hedging Instrument [Member] | Commodity Contracts Losses [Member] | Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability derivatives	0	0	2.4
Not Designated as Hedging Instrument [Member] | Commodity Contracts Losses [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Asset derivatives	$ 0	$ 0	$ 0