RATE AND OTHER REGULATORY MATTERS NARRATIVE (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Deferred Income Tax Charge [Member]
Regulatory Asset, Amortization Period	85 years
Asset Retirement Obligation Costs [Member]
Regulatory Asset, Amortization Period	107 years
SCE&G
EPC Contract Amendment, Fixed Price Option, Price For New Nuclear Construction After June 2015	$ 831
Total New Nuclear Project Cost Approved By SCPSC In September 2015	6,800
EPC Contract Amendment, Total New Nuclear Project Cost Including Amendment Increase	$ 7,700
SCE&G | Pension Costs [Member]
Regulatory Asset, Amortization Period	11 years
SCE&G | Pension costs, gas [Member]
Regulatory Asset, Amortization Period	2027 years
SCE&G | Pension costs, electric [Member]
Regulatory Asset, Amortization Period	2044 years
PSNC Energy [Member]
MPG environmental remediation	6.9
PSNC Energy [Member] | Pipeline integrity management costs [Member]
Regulatory Asset, Amortization Period	2021 years