CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Common Stock, Shares, Outstanding	143.0	143.0
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	$ 140	$ 133
Public Utilities, Property, Plant and Equipment, Net	10,882	10,648
Allowance for Doubtful Accounts Receivable, Current	4	6
Write-down, Goodwill	230	230
Assets, Current	1,420	1,851
Regulated Entity, Other Assets, Noncurrent	$ 5,971	$ 5,766
SCEG
Common Stock, Shares, Outstanding	40.3	40.3
Public Utilities, Property, Plant and Equipment, Net	$ 8,690	$ 8,620
Allowance for Doubtful Accounts Receivable, Current	3	4
Assets, Current	1,352	1,477
Regulated Entity, Other Assets, Noncurrent	5,874	5,640
SCEG | Variable Interest Entity, Primary Beneficiary [Member]
Public Utilities, Property, Plant and Equipment, Net	676	711
Assets, Current	74	191
Regulated Entity, Other Assets, Noncurrent	$ 34	$ 50