CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Revenues:
Electric Domestic Regulated Revenue	$ 2,659	$ 2,614	$ 2,551
Regulated Operating Revenue, Gas	874	788	811
Gas-nonregulated	874	825	1,018
Regulated and Unregulated Operating Revenue	4,407	4,227	4,380
Utilities Operating Expense [Abstract]
Fuel used in electric generation	594	576	660
Purchased power	80	64	52
Gas purchased for resale	1,156	1,054	1,287
Other operation and maintenance	737	755	715
Utilities Operating Expense, Impairments	1,118
Depreciation and amortization	382	371	358
Other taxes	264	254	234
Utilities Operating Expense	4,331	3,074	3,306
Gain (Loss) On Disposition Of Regulated Business Net Of Transaction Costs			234
Operating Income	76	1,153	1,308
Other Nonoperating Income (Expense)	(56)	(55)	(42)
Other Income (Expense):
Other income	79	64	75
Other expenses	(46)	(38)	(60)
Gain (Loss) On Disposition Of Unregulated Business Net Of Transaction Costs			107
Interest charges, net of allowance for borrowed funds used during construction	(363)	(342)	(318)
Allowance for equity funds used during construction	23	29	27
Total Other Expense	56	55	42
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(231)	866	1,139
Income Tax Expense (Benefit)	(112)	271	393
Income Available to Common Shareholders	$ (119)	$ 595	$ 746
Earnings Per Share, Basic and Diluted	$ (0.83)	$ 4.16	$ 5.22
Dividends Common Stock Declared	$ 350	$ 329	$ 312
Weighted Average Common Shares Outstanding (millions)
Weighted Average Number of Shares Outstanding, Basic	143	143	143
Dividends Declared Per Share of Common Stock (in dollars per share)	$ 2.45	$ 2.30	$ 2.18
SCE&G
Operating Revenues:
Regulated Operating Revenue	$ 3,070	$ 2,986	$ 2,930
Utilities Operating Expense [Abstract]
Utilities Operating Expense, Impairments	1,118
Utilities Operating Expense	3,160	1,973	1,996
Operating Income	(90)	1,013	934
Other Income (Expense):
Other income	45	29	31
Other expenses	(25)	(24)	(31)
Interest charges, net of allowance for borrowed funds used during construction	(288)	(270)	(248)
Allowance for equity funds used during construction	15	26	25
Total Other Expense	35	31	25
Income Tax Expense (Benefit)	(171)	248	231
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(172)	526	480
Net Income (Loss) Attributable to Noncontrolling Interest	13	13	14
Earnings Available to Common Shareholder	(185)	513	466
Subsidiaries [Member] | SCE&G
Operating Revenues:
Electric Domestic Regulated Revenue	2,659	2,614	2,551
Regulated Operating Revenue, Gas	405	366	372
Utilities Operating Expense [Abstract]
Fuel used in electric generation	465	472	559
Purchased power	80	64	52
Gas purchased for resale	206	174	162
Other operation and maintenance	417	403	380
Utilities Operating Expense, Impairments	1,118
Depreciation and amortization	312	302	294
Other taxes	241	227	211
Other Nonoperating Income (Expense)	35	31	25
Other Income (Expense):
Interest charges, net of allowance for borrowed funds used during construction	(288)	(270)	(248)
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	(343)	774	711
Income Tax Expense (Benefit)	(171)	248	231
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(172)	526	480
Net Income (Loss) Attributable to Noncontrolling Interest	13	13	14
Earnings Available to Common Shareholder	(185)	513	466
Dividends Common Stock Declared	323	305	285
Affiliated Entity [Member] | SCE&G
Operating Revenues:
Electric Domestic Regulated Revenue	5	5	6
Regulated Operating Revenue, Gas	1	1	1
Utilities Operating Expense [Abstract]
Fuel used in electric generation	129	104	102
Gas purchased for resale	0	9	31
Other operation and maintenance	187	211	199
Other taxes	$ 5	$ 7	$ 6