SEGMENT OF BUSINESS INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Total	$ 17,654				$ 18,739				$ 17,654	$ 18,739	$ 18,707
Additions to Other Assets, Amount									890	1,225	1,579
Deferred Tax Assets, Gross	0				0				0	0	0
Regulated and Unregulated Operating Revenue	1,103	$ 926	$ 843	$ 1,180	1,157	$ 1,076	$ 1,001	$ 1,173	4,052	4,407	4,227
Intersegment Revenue									0	0	0
Operating Income	(1,204)	183	103	189	(608)	122	251	320	(729)	85	1,167
Interest Expense									384	363	342
Depreciation, Depletion and Amortization									403	382	371
Income Tax Expense (Benefit)									(412)	(112)	271
Income Available to Common Shareholders	(772)	67	8	169	(445)	34	121	171	(528)	(119)	595
Regulated Operating Revenue, Gas									934	874	788
Electric Operations
Segment Reporting Information [Line Items]
Total	7,988				11,979				7,988	11,979	11,929
Additions to Other Assets, Amount									973	216	1,275
Deferred Tax Assets, Gross	(4)				(6)				(4)	(6)	(9)
Regulated and Unregulated Operating Revenue									2,322	2,659	2,614
Intersegment Revenue									5	5	5
Operating Income									(894)	(154)	969
Interest Expense									18	19	17
Depreciation, Depletion and Amortization									307	295	287
Income Tax Expense (Benefit)									9	8	8
Gas Distribution
Segment Reporting Information [Line Items]
Total	3,517				3,259				3,517	3,259	2,892
Additions to Other Assets, Amount									345	417	276
Deferred Tax Assets, Gross	(17)				(25)				(17)	(25)	(32)
Regulated and Unregulated Operating Revenue									934	874	788
Intersegment Revenue									1	2	2
Operating Income									173	187	149
Interest Expense									37	28	25
Depreciation, Depletion and Amortization									94	85	82
Income Tax Expense (Benefit)									26	41	32
Gas Marketing [Member]
Segment Reporting Information [Line Items]
Total	305				230				305	230	230
Additions to Other Assets, Amount									2	2	2
Deferred Tax Assets, Gross	(2)				(9)				(2)	(9)	(11)
Regulated and Unregulated Operating Revenue									796	874	825
Intersegment Revenue									139	127	111
Interest Expense									1	1	1
Depreciation, Depletion and Amortization									2	2	2
Income Tax Expense (Benefit)									15	25	19
Income Available to Common Shareholders									43	27	30
All Other [member]
Segment Reporting Information [Line Items]
Total	1,212				1,042				1,212	1,042	1,124
Additions to Other Assets, Amount									8	7	11
Deferred Tax Assets, Gross	0				0				0	0	0
Regulated and Unregulated Operating Revenue									0	0	0
Intersegment Revenue									470	389	414
Operating Income									0	0	0
Interest Expense									0	0	0
Depreciation, Depletion and Amortization									15	16	16
Income Tax Expense (Benefit)									(25)	(7)	0
Income Available to Common Shareholders									(90)	(46)	(18)
Adjustments/Eliminations
Segment Reporting Information [Line Items]
Total	4,632				2,229				4,632	2,229	2,532
Additions to Other Assets, Amount									(438)	583	15
Deferred Tax Assets, Gross	23				40				23	40	52
Regulated and Unregulated Operating Revenue									0	0	0
Intersegment Revenue									(615)	(523)	(532)
Operating Income									(8)	52	49
Interest Expense									328	315	299
Depreciation, Depletion and Amortization									(15)	(16)	(16)
Income Tax Expense (Benefit)									(437)	(179)	212
Income Available to Common Shareholders									(481)	(100)	583
SCE&G
Segment Reporting Information [Line Items]
Total	14,963				15,946				14,963	15,946	16,091
Additions to Other Assets, Amount									633	928	1,399
Deferred Tax Assets, Gross	0				0				0	0	0
Regulated Operating Revenue	689	739	632	702	739	856	756	719	2,762	3,070	2,986
Operating Income	(1,271)	$ 212	$ 107	$ 121	(680)	$ 124	$ 247	$ 226	(831)	(83)	1,025
Interest Expense									303	288	270
Depreciation, Depletion and Amortization									327	312	302
Income Tax Expense (Benefit)									(416)	(171)	248
Regulated Operating Revenue, Gas									434	405	366
SCE&G | Electric Operations
Segment Reporting Information [Line Items]
Total	7,988								7,988		11,929
Additions to Other Assets, Amount									973		1,275
Deferred Tax Assets, Gross	(4)								(4)		(9)
Regulated Operating Revenue									2,327
Operating Income									(894)		969
Interest Expense									18	19	17
Depreciation, Depletion and Amortization									307	295	287
SCE&G | Gas Distribution
Segment Reporting Information [Line Items]
Total	934				869				934	869	825
Additions to Other Assets, Amount									90	65	78
Regulated and Unregulated Operating Revenue									435	406	367
Regulated Operating Revenue									435
Operating Income									63	71	56
Depreciation, Depletion and Amortization									32	30	28
SCE&G | Adjustments/Eliminations
Segment Reporting Information [Line Items]
Total	6,041				3,098				6,041	3,098	3,337
Additions to Other Assets, Amount									(430)	647	46
Deferred Tax Assets, Gross	$ 4				$ 6				4	6	9
Operating Income											0
Interest Expense									285	269	253
Depreciation, Depletion and Amortization									(12)	(13)	(13)
External revenue [Member] | SCE&G
Segment Reporting Information [Line Items]
Regulated and Unregulated Operating Revenue									$ 2,327	$ 2,664	$ 2,619