Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net cash paid for capitalized interest	$ 124	$ 111	$ 92
Alabama Power [Member]
Net cash paid for capitalized interest	22	18	11
Georgia Power [Member]
Net cash paid for capitalized interest	16	18	14
Gulf Power [Member]
Net cash paid for capitalized interest	6	5	3
Mississippi Power [Member]
Net cash paid for capitalized interest	66	69	54
Southern Power [Member]
Net cash paid for capitalized interest	$ 14	$ 0	$ 9