Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net cash paid for capitalized interest			$ 72	$ 94
ALABAMA POWER CO
Net cash paid for capitalized interest			10	8
GEORGIA POWER CO
Net cash paid for capitalized interest			17	15
GULF POWER CO
Net cash paid for capitalized interest			0	0
MISSISSIPPI POWER CO
Interest paid			73	72
Net cash paid for capitalized interest			28	36
SOUTHERN POWER CO
Net cash paid for capitalized interest			7	$ 32
SOUTHERN Co GAS
Net cash paid for capitalized interest	$ 2		$ 9
Predecessor | SOUTHERN Co GAS
Net cash paid for capitalized interest		$ 3