CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Revenues:
Electric Domestic Regulated Revenue	$ 577	$ 592
Regulated Operating Revenue, Gas	322	299
Gas-nonregulated	274	281
Regulated and Unregulated Operating Revenue	1,173	1,172
Operating Expenses [Abstract]
Fuel used in electric generation	136	136
Purchased power	11	11
Gas purchased for resale	370	359
Other operation and maintenance	179	181
Depreciation and amortization	95	91
Other taxes	66	63
Total Operating Expenses	857	841
Operating Income	316	331
Other Income (Expense):
Other income	17	16
Other expense	(10)	(14)
Interest Expense	(87)	(83)
Allowance for equity funds used during construction	9	5
Total Other Expense	(71)	(76)
Income Before Income Tax Expense	245	255
Income Tax Expense	74	79
Net Income	$ 171	$ 176
Earnings Per Share, Basic and Diluted	$ 1.19	$ 1.23
Per Common Share Data
Weighted Average Number of Shares Outstanding, Basic and Diluted	142.9	142.9
Weighted Average Common Shares Outstanding (millions)
Dividends, Common Stock	$ 87	$ 82
Common Stock, Dividends, Per Share, Declared	$ 0.6125	$ 0.575
SCEG
Operating Revenues:
Electric Domestic Regulated Revenue	$ 577	$ 592
Regulated Operating Revenue, Gas	141	124
Regulated Operating Revenue	719	717
Operating Expenses [Abstract]
Fuel used in electric generation	112	119
Purchased power	11	11
Gas purchased for resale	66	50
Other operation and maintenance	101	96
Depreciation and amortization	77	74
Other taxes	60	56
Total Operating Expenses	497	481
Operating Income	222	236
Other Income (Expense):
Other income	8	5
Other expense	(6)	(8)
Interest Expense	(69)	(66)
Allowance for equity funds used during construction	9	5
Total Other Expense	(58)	(64)
Income Before Income Tax Expense	164	172
Income Tax Expense	52	56
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	112	116
Net Income (Loss) Attributable to Noncontrolling Interest	(3)	(3)
Earnings Available to Common Shareholder	109	113
Weighted Average Common Shares Outstanding (millions)
Dividends, Common Stock	79	74
Affiliated Entity [Member] | SCEG
Operating Revenues:
Electric Domestic Regulated Revenue	1	1
Operating Expenses [Abstract]
Fuel used in electric generation	24	17
Gas purchased for resale	0	6
Other operation and maintenance	45	50
Other taxes	$ 1	$ 2