AFFILIATED TRANSACTIONS Canadys Refined Coal (Tables) - USD ($)
$ in Millions

3 Months Ended

9 Months Ended

Sep. 30, 2017

Sep. 30, 2016

Sep. 30, 2017

Sep. 30, 2016

Canadys Refined Coal [Member]

Related Party Transactions [Abstract]

Related Party Transaction, Purchases from Related Party

$ 47.5

$ 41.8

$ 144.9

$ 138.6

Related Party Transaction [Line Items]

Schedule of Related Party Transactions [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
Millions of Dollars	2017		2016		2017		2016
Purchases from Canadys Refined Coal, LLC	$	47.5	$	41.8	$	144.9	$	138.6
Sales to Canadys Refined Coal, LLC	47.2		41.6		144.0		137.8

Millions of Dollars	September 30, 2017		December 31, 2016
Receivable from Canadys Refined Coal, LLC	$	7.6	$	16.0
Payable to Canadys Refined Coal, LLC	7.7		16.1

SCEG

Related Party Transaction [Line Items]

Schedule of Related Party Transactions [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
Millions of Dollars	2017		2016		2017		2016
Purchases from SCANA Energy	$	35.3	$	34.8	$	93.4	$	83.1
Direct and Allocated Costs from SCANA Services	78.1		80.4		233.6		236.4

Millions of Dollars	September 30, 2017		December 31, 2016
Payable to SCANA Energy	$	10.7	$	8.8
Payable to SCANA Services	45.3		63.5

SCEG | Canadys Refined Coal [Member]

Related Party Transaction [Line Items]

Schedule of Related Party Transactions [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
Millions of Dollars	2017		2016		2017		2016
Purchases from Canadys Refined Coal, LLC	$	47.5	$	41.8	$	144.9	$	138.6
Sales to Canadys Refined Coal, LLC	47.2		41.6		144.0		137.8

Millions of Dollars	September 30, 2017		December 31, 2016
Receivable from Canadys Refined Coal, LLC	$	7.6	$	16.0
Payable to Canadys Refined Coal, LLC	7.7		16.1