SEGMENT OF BUSINESS INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue	$ 786	$ 817	$ 2,042	$ 2,035
Revenues	0	0	0	0
Net Income (Loss) Available to Common Stockholders, Basic	34	189	326	471
Operating Income	120	348	685	900
Regulated Operating Revenue, Gas	123	111	584	538
Regulated and Unregulated Operating Revenue	1,076	1,093	3,249	3,171
Segment Assets	20,019		20,019		$ 18,707
Electric Operations
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue	786	817	2,042	2,035
Revenues	1	1	4	4
Operating Income	126	364	549	784
Segment Assets	12,294		12,294		11,929
Gas Distribution
Segment Reporting Information [Line Items]
Revenues	0	0	1	1
Operating Income	(7)	(14)	109	79
Regulated and Unregulated Operating Revenue	123	111	584	538
Segment Assets	3,080		3,080		2,892
Gas Marketing [Member]
Segment Reporting Information [Line Items]
Revenues	35	35	93	83
Net Income (Loss) Available to Common Stockholders, Basic	1	(1)	17	23
Regulated and Unregulated Operating Revenue	167	165	623	598
Segment Assets	187		187		230
All Other [member]
Segment Reporting Information [Line Items]
Revenues	90	100	286	302
Net Income (Loss) Available to Common Stockholders, Basic	(7)	(7)	(14)	(14)
Operating Income	0	0	0	0
Regulated and Unregulated Operating Revenue	0	0	0	0
Segment Assets	970		970		1,124
Adjustments/Eliminations
Segment Reporting Information [Line Items]
Revenues	(126)	(136)	(384)	(390)
Net Income (Loss) Available to Common Stockholders, Basic	40	197	323	462
Operating Income	1	(2)	27	37
Regulated and Unregulated Operating Revenue	0	0	0	0
Segment Assets	3,488		3,488		2,532
SCEG
Segment Reporting Information [Line Items]
Operating Income	123	359	591	816
Net Income (Loss) Attributable to Parent	39	201	270	423
Regulated Operating Revenue	856	882	2,331	2,292
Segment Assets	17,433		17,433		16,091
SCEG | Electric Operations
Segment Reporting Information [Line Items]
Electric Domestic Regulated Revenue	787	818	2,046	2,039
Operating Income	125	364	549	784
Segment Assets	12,294		12,294		11,929
SCEG | Gas Distribution
Segment Reporting Information [Line Items]
Operating Income	(2)	(5)	42	32
Regulated and Unregulated Operating Revenue	69	64	285	253
Segment Assets	856		856		825
SCEG | Adjustments/Eliminations
Segment Reporting Information [Line Items]
Operating Income	0	0	0	0
Regulated and Unregulated Operating Revenue	0	0	0	0
Net Income (Loss) Attributable to Parent	39	$ 201	270	$ 423
Segment Assets	$ 4,283		$ 4,283		$ 3,337