FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Carrying Amount
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	$ 5,153.0	$ 4,653.0
Estimated Fair Value
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	6,241.6	5,479.2
SCE&G | Carrying Amount
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	3,753.6	3,241.5
SCE&G | Estimated Fair Value
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	$ 4,661.0	$ 3,920.3