Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Net cash paid for capitalized interest	$ 35	$ 55
ALABAMA POWER CO
Net cash paid for capitalized interest	10	6
GEORGIA POWER CO
Net cash paid for capitalized interest	12	11
GULF POWER CO
Net cash paid for capitalized interest	0	0
MISSISSIPPI POWER CO
Interest paid	39	53
Net cash paid for capitalized interest	0	27
SOUTHERN POWER CO
Net cash paid for capitalized interest	10	4
SOUTHERN Co GAS
Net cash paid for capitalized interest	$ 3	$ 7