CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Available to Common Shareholders	$ (119)	$ 595	$ 746
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	(7)	4	(12)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(1)	17	(10)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	0	(1)	0
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	(1)	0
Other Comprehensive Income (Loss), Net of Tax	(1)	16	10
Net Income (Loss) Attributable to Parent [Abstract]
Total Comprehensive Income (Loss)	(120)	611	756
SCE&G
Other Comprehensive Income (Loss), Net of Tax			0
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(172)	526	480
Other Comprehensive Income (Loss)
Amortization of deferred employee benefit plan costs reclassified to net income, net of tax	0		0
Less comprehensive income attributable to noncontrolling interest	13	13	14
Net Income (Loss) Attributable to Parent [Abstract]
Total Comprehensive Income (Loss)	(173)	526	480
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	(172)	526	480
SCEG excluding VIEs [Member]
Income Available to Common Shareholders	(185)	513	466
Net Income (Loss) Attributable to Parent [Abstract]
Total Comprehensive Income (Loss)	(185)	513	466
Interest Rate Contract
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	7	7	7
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (1)	$ 6	$ 15