FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Carrying Amount
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	$ 5,450.9	$ 5,121.0
Estimated Fair Value
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	5,936.7	6,115.0
SCEG | Carrying Amount
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	4,056.4	3,722.0
SCEG | Estimated Fair Value
Financial instruments for which the carrying amount may not equal estimated fair value
Long-term debt	$ 4,454.4	$ 4,543.1