Components of the net periodic benefit costs for the three and nine months ended September 30, 2015 and 2014 were as follows:



Pension Plans	Southern Company			Alabama Power			Georgia Power			Gulf Power			Mississippi Power
	(in millions)
Three Months Ended September 30, 2015
Service cost	$	65		$	14		$	18		$	3		$	3
Interest cost	111			26			38			5			5
Expected return on plan assets	(181		)	(44		)	(62		)	(8		)	(8		)
Amortization:
Prior service costs	6			2			2			1			—
Net (gain)/loss	53			14			19			2			3
Net cost	$	54		$	12		$	15		$	3		$	3
Nine Months Ended September 30, 2015
Service cost	$	193		$	44		$	54		$	9		$	9
Interest cost	333			79			115			15			16
Expected return on plan assets	(543		)	(133		)	(188		)	(24		)	(25		)
Amortization:
Prior service costs	19			5			7			1			1
Net (gain)/loss	161			41			57			7			8
Net cost	$	163		$	36		$	45		$	8		$	9
Three Months Ended September 30, 2014
Service cost	$	53		$	12		$	16		$	4		$	3
Interest cost	109			26			39			4			5
Expected return on plan assets	(161		)	(42		)	(57		)	(7		)	(8		)
Amortization:
Prior service costs	6			2			2			—			—
Net (gain)/loss	28			7			10			1			2
Net cost	$	35		$	5		$	10		$	2		$	2
Nine Months Ended September 30, 2014
Service cost	$	160		$	36		$	47		$	8		$	8
Interest cost	326			78			115			14			15
Expected return on plan assets	(484		)	(126		)	(170		)	(21		)	(22		)
Amortization:
Prior service costs	19			5			7			1			1
Net (gain)/loss	83			23			30			3			4
Net cost	$	104		$	16		$	29		$	5		$	6



Postretirement Benefits	Southern Company			Alabama Power			Georgia Power			Gulf Power			Mississippi Power
	(in millions)
Three Months Ended September 30, 2015
Service cost	$	6		$	1		$	2		$	1		$	—
Interest cost	20			5			9			—			1
Expected return on plan assets	(15		)	(6		)	(6		)	—			—
Amortization:
Prior service costs	1			2			—			—			—
Net (gain)/loss	4			—			2			—			—
Net cost	$	16		$	2		$	7		$	1		$	1
Nine Months Ended September 30, 2015
Service cost	$	17		$	4		$	5		$	1		$	1
Interest cost	59			15			26			2			3
Expected return on plan assets	(44		)	(19		)	(18		)	(1		)	(1		)
Amortization:
Prior service costs	3			3			—			—			—
Net (gain)/loss	13			1			8			—			—
Net cost	$	48		$	4		$	21		$	2		$	3
Three Months Ended September 30, 2014
Service cost	$	5		$	1		$	2		$	—		$	—
Interest cost	19			5			9			—			—
Expected return on plan assets	(14		)	(6		)	(6		)	—			—
Amortization:
Prior service costs	1			1			—			—			—
Net (gain)/loss	1			—			—			—			—
Net cost	$	12		$	1		$	5		$	—		$	—
Nine Months Ended September 30, 2014
Service cost	$	16		$	4		$	5		$	1		$	1
Interest cost	59			15			26			2			2
Expected return on plan assets	(44		)	(19		)	(19		)	(1		)	(1		)
Amortization:
Prior service costs	3			3			—			—			—
Net (gain)/loss	2			—			1			—			—
Net cost	$	36		$	3		$	13		$	2		$	2