Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net cash paid for capitalized interest	$ 17	$ 25
ALABAMA POWER CO
Net cash paid for capitalized interest	5	3
GEORGIA POWER CO
Net cash paid for capitalized interest	6	5
GULF POWER CO
Net cash paid for capitalized interest	0	0
MISSISSIPPI POWER CO
Interest paid	21	25
Net cash paid for capitalized interest	0	12
SOUTHERN POWER CO
Net cash paid for capitalized interest	5	2
SOUTHERN Co GAS
Net cash paid for capitalized interest	$ 1	$ 3