FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES (Details 2) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Carrying Amount
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	$ 4,664.9	$ 4,488.3
Estimated Fair Value
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	$ 5,016.2	$ 4,840.5