CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues:
Electric Domestic Regulated Revenue	$ 679	$ 626	$ 1,256	$ 1,217
Regulated Operating Revenue, Gas	140	127	461	426
Gas-nonregulated	182	152	456	434
Regulated and Unregulated Operating Revenue	1,001	905	2,173	2,077
Operating Expenses [Abstract]
Fuel used in electric generation	161	130	297	267
Purchased power	21	17	32	29
Gas purchased for resale	227	192	597	551
Other operation and maintenance	181	191	360	371
Depreciation and amortization	95	92	189	183
Other taxes	67	62	133	125
Total Operating Expenses	752	684	1,608	1,526
Operating Income	249	221	565	551
Other Income (Expense):
Other income	16	14	33	30
Other expense	(9)	(10)	(18)	(24)
Interest Expense	(88)	(83)	(175)	(166)
Allowance for equity funds used during construction	9	9	18	15
Total Other Expense	(72)	(70)	(142)	(145)
Income Before Income Tax Expense	177	151	423	406
Income Tax Expense	56	46	131	125
Net Income	$ 121	$ 105	$ 292	$ 281
Earnings Per Share, Basic and Diluted	$ 0.85	$ 0.74	$ 2.04	$ 1.97
Per Common Share Data
Weighted Average Number of Shares Outstanding, Basic and Diluted	142.9	142.9	142.9	142.9
Weighted Average Common Shares Outstanding (millions)
Dividends, Common Stock			$ 175	$ 164
Common Stock, Dividends, Per Share, Declared	$ 0.6125	$ 0.575	$ 1.2250	$ 1.150
SCEG
Operating Revenues:
Regulated Operating Revenue	$ 756	$ 692	$ 1,476	$ 1,409
Operating Expenses [Abstract]
Total Operating Expenses	510	470	1,008	951
Operating Income	246	222	468	458
Other Income (Expense):
Other income	7	6	15	12
Other expense	(6)	(6)	(11)	(14)
Interest Expense	(69)	(65)	(138)	(131)
Allowance for equity funds used during construction	8	8	16	12
Total Other Expense	(60)	(57)	(118)	(121)
Income Before Income Tax Expense	186	165	350	337
Income Tax Expense	60	52	112	108
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	126	113	238	229
Net Income (Loss) Attributable to Noncontrolling Interest	(3)	(3)	(7)	(6)
Earnings Available to Common Shareholder	123	110	231	223
Weighted Average Common Shares Outstanding (millions)
Dividends, Common Stock	81	75	160	149
Subsidiaries [Member] | SCEG
Operating Revenues:
Electric Domestic Regulated Revenue	678	625	1,256	1,217
Regulated Operating Revenue, Gas	75	64	216	188
Operating Expenses [Abstract]
Fuel used in electric generation	126	107	239	227
Purchased power	21	17	32	29
Gas purchased for resale	42	31	108	80
Other operation and maintenance	96	101	197	197
Depreciation and amortization	77	75	154	149
Other taxes	60	56	120	111
Affiliated Entity [Member] | SCEG
Operating Revenues:
Electric Domestic Regulated Revenue	2	2	3	3
Regulated Operating Revenue, Gas	1	1	1	1
Operating Expenses [Abstract]
Fuel used in electric generation	35	23	59	40
Gas purchased for resale	0	3	0	9
Other operation and maintenance	51	55	96	105
Other taxes	$ 2	$ 2	$ 3	$ 4