Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2022

Retirement Benefits [Abstract]

Schedule of Pension Plans and Postretirement Plans

Components of the net periodic benefit costs for the three and six months ended June 30, 2022 and 2021 are presented in the following tables.

	Southern Company		Alabama Power		Georgia Power		Mississippi Power		Southern Power		Southern Company Gas
	(in millions)
Three Months Ended June 30, 2022
Pension Plans
Service cost	$	103	$	24	$	26	$	4	$	3	$	8
Interest cost	102		24		30		4		1		7
Expected return on plan assets	(317)		(75)		(100)		(14)		(4)		(24)
Amortization:
Prior service costs	—		—		1		—		—		—
Regulatory asset	—		—		—		—		—		4
Net loss	60		15		19		4		—		1
Net periodic pension cost (income)	$	(52)	$	(12)	$	(24)	$	(2)	$	—	$	(4)
Postretirement Benefits
Service cost	$	5	$	2	$	1	$	—	$	—	$	—
Interest cost	11		2		3		1		—		1
Expected return on plan assets	(20)		(8)		(6)		(1)		—		(1)
Amortization:
Regulatory asset	—		—		—		—		—		1
Net loss	—		—		1		—		—		—
Net periodic postretirement benefit cost (income)	$	(4)	$	(4)	$	(1)	$	—	$	—	$	1
Six Months Ended June 30, 2022
Pension Plans
Service cost	$	206	$	49	$	52	$	8	$	5	$	17
Interest cost	204		48		61		9		3		14
Expected return on plan assets	(633)		(152)		(199)		(29)		(8)		(46)
Amortization:
Prior service costs	—		—		1		—		—		(1)
Regulatory asset	—		—		—		—		—		8
Net loss	120		31		37		7		1		3
Net periodic pension cost (income)	$	(103)	$	(24)	$	(48)	$	(5)	$	1	$	(5)
Postretirement Benefits
Service cost	$	11	$	3	$	3	$	—	$	—	$	1
Interest cost	21		5		7		1		—		2
Expected return on plan assets	(40)		(16)		(13)		(1)		—		(3)
Amortization:
Regulatory asset	—		—		—		—		—		3
Net (gain)/loss	—		—		1		—		—		(1)
Net periodic postretirement benefit cost (income)	$	(8)	$	(8)	$	(2)	$	—	$	—	$	2

	Southern Company		Alabama Power		Georgia Power		Mississippi Power		Southern Power		Southern Company Gas
	(in millions)
Three Months Ended June 30, 2021
Pension Plans
Service cost	$	108	$	25	$	28	$	5	$	3	$	9
Interest cost	86		21		26		4		1		6
Expected return on plan assets	(297)		(71)		(94)		(13)		(4)		(22)
Amortization:
Prior service costs	—		—		1		—		—		—
Regulatory asset	—		—		—		—		—		4
Net loss	79		20		25		3		1		3
Net periodic pension cost (income)	$	(24)	$	(5)	$	(14)	$	(1)	$	1	$	—
Postretirement Benefits
Service cost	$	6	$	2	$	1	$	—	$	—	$	1
Interest cost	9		2		3		1		—		1
Expected return on plan assets	(19)		(7)		(6)		(1)		—		(2)
Amortization:
Prior service costs	(1)		—		—		—		—		—
Regulatory asset	—		—		—		—		—		1
Net loss	1		—		—		—		—		—
Net periodic postretirement benefit cost (income)	$	(4)	$	(3)	$	(2)	$	—	$	—	$	1
Six Months Ended June 30, 2021
Pension Plans
Service cost	$	217	$	51	$	56	$	9	$	5	$	18
Interest cost	173		41		52		8		2		12
Expected return on plan assets	(595)		(143)		(188)		(27)		(7)		(43)
Amortization:
Prior service costs	—		—		1		—		—		(1)
Regulatory asset	—		—		—		—		—		8
Net loss	157		41		50		7		2		6
Net periodic pension cost (income)	$	(48)	$	(10)	$	(29)	$	(3)	$	2	$	—
Postretirement Benefits
Service cost	$	12	$	3	$	3	$	—	$	—	$	1
Interest cost	17		4		6		1		—		2
Expected return on plan assets	(38)		(14)		(13)		(1)		—		(4)
Amortization:
Prior service costs	(1)		—		—		—		—		—
Regulatory asset	—		—		—		—		—		3
Net (gain)/loss	2		—		1		—		—		(1)
Net periodic postretirement benefit cost (income)	$	(8)	$	(7)	$	(3)	$	—	$	—	$	1