v3.10.0.1

AFFILIATED TRANSACTIONS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Proceeds from Equity Method Investment, Distribution	$ 2.3	$ 2.8	$ 3.7
Equity Method Investments	4.2	4.6	5.5
Canadys Refined Coal [Member]
Related Party Transaction [Line Items]
Related Party Tax Expense, Due to Affiliates, Current	6.8	4.9
Related Party Transaction, Purchases from Related Party	149.9	162.1	161.8
Related Party Tax Expense, Due from Affiliates, Current	$ 6.8	4.9
Equity Method Investment, Ownership Percentage	40.00%
Sales to Affiliate	$ 149.0	161.1	160.8
Energy Marketing [Member]
Related Party Transaction [Line Items]
Utilities Operating Expense, Gas and Petroleum Purchased, affiliate	139.0	127.4	111.5
SCE&G
Related Party Transaction [Line Items]
Utilities Operating Expense, Gas and Petroleum Purchased, affiliate			9.0
Related Party Tax Expense, Due to Affiliates, Current	14.1	10.0
Accounts Payable, Related Parties, Current	37.7	42.0
SCANA Services [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$ 283.3	$ 302.8	$ 337.7

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