Stockholders' Equity - Earnings per Share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings per Share
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	15	8	1	17
Southern Company [Member]
Earnings per Share
As reported shares	909	895	910	892
Effect of options and performance share award units	3	4	4	4
Diluted shares	912	899	914	896