Retirement Benefits (Tables)

3 Months Ended

Mar. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Pension Plans and Postretirement Plans

Components of the net periodic benefit costs for the three months ended March 31, 2015 and 2014 were as follows:

Pension Plans	Southern Company			Alabama Power			Georgia Power			Gulf Power			Mississippi Power
	(in millions)
Three Months Ended March 31, 2015
Service cost	$	64		$	15		$	18		$	3		$	3
Interest cost	111			26			38			5			5
Expected return on plan assets	(181		)	(45		)	(63		)	(8		)	(8		)
Amortization:
Prior service costs	6			2			3			—			—
Net (gain)/loss	54			14			19			3			3
Net cost	$	54		$	12		$	15		$	3		$	3
Three Months Ended March 31, 2014
Service cost	$	53		$	12		$	16		$	3		$	3
Interest cost	109			26			38			5			5
Expected return on plan assets	(161		)	(42		)	(57		)	(7		)	(7		)
Amortization:
Prior service costs	6			1			3			—			—
Net (gain)/loss	28			8			10			1			1
Net cost	$	35		$	5		$	10		$	2		$	2

Postretirement Benefits	Southern Company			Alabama Power			Georgia Power			Gulf Power		Mississippi Power
	(in millions)
Three Months Ended March 31, 2015
Service cost	$	6		$	1		$	2		$	—	$	—
Interest cost	19			5			8			1		1
Expected return on plan assets	(15		)	(6		)	(6		)	—		—
Amortization:
Prior service costs	1			1			—			—		—
Net (gain)/loss	5			—			3			—		—
Net cost	$	16		$	1		$	7		$	1	$	1
Three Months Ended March 31, 2014
Service cost	$	5		$	1		$	2		$	—	$	—
Interest cost	20			5			8			1		1
Expected return on plan assets	(15		)	(6		)	(6		)	—		—
Amortization:
Prior service costs	1			1			—			—		—
Net (gain)/loss	1			—			—			—		—
Net cost	$	12		$	1		$	4		$	1	$	1