FAIR VALUE MEASUREMENTS, INCLUDING DERIVATIVES (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

 Fair value measurements, and the level within the fair value hierarchyin which the measurements fall, were as follows:

	As of March 31, 2018						As of December 31, 2017
	The Company				Consolidated SCE&G		The Company				Consolidated SCE&G
Millions of dollars	Level 1		Level 2		Level 2		Level 1		Level 2		Level 1		Level 2
Assets:
Available for sale securities	$	19	—		—		$	119	—		$	100	—
Held to maturity securities	—		$	6	—		—		$	6	—		—
Interest rate contracts	—		—		—		—		54		—		$	54
Commodity contracts	1		—		—		1		—		—		—
Energy management contracts	—		3		—		—		4		—		—
Liabilities:
Interest rate contracts	—		25		$	11	—		32		—		15
Commodity contracts	1		—		—		2		1		—		—
Energy management contracts	1		4		—		1		4		—		—

Fair Value, by Balance Sheet Grouping [Table Text Block]

Financial instruments for which the carrying amount may not equal estimated fair value were as follows:

Long-Term Debt	March 31, 2018				December 31, 2017
Millions of dollars	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
The Company	$	6,728.9	$	7,220.1	$	6,632.9	$	7,399.7
Consolidated SCE&G	5,259.0		5,649.1		5,163.3		5,790.3

SCEG

Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

Fair value measurements, and the level within the fair value hierarchyin which the measurements fall, were as follows:

	As of March 31, 2018						As of December 31, 2017
	The Company				Consolidated SCE&G		The Company				Consolidated SCE&G
Millions of dollars	Level 1		Level 2		Level 2		Level 1		Level 2		Level 1		Level 2
Assets:
Available for sale securities	$	19	—		—		$	119	—		$	100	—
Held to maturity securities	—		$	6	—		—		$	6	—		—
Interest rate contracts	—		—		—		—		54		—		$	54
Commodity contracts	1		—		—		1		—		—		—
Energy management contracts	—		3		—		—		4		—		—
Liabilities:
Interest rate contracts	—		25		$	11	—		32		—		15
Commodity contracts	1		—		—		2		1		—		—
Energy management contracts	1		4		—		1		4		—		—

Fair Value, by Balance Sheet Grouping [Table Text Block]

Financial instruments for which the carrying amount may not equal estimated fair value were as follows:

Long-Term Debt	March 31, 2018				December 31, 2017
Millions of dollars	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
The Company	$	6,728.9	$	7,220.1	$	6,632.9	$	7,399.7
Consolidated SCE&G	5,259.0		5,649.1		5,163.3		5,790.3