Retirement Benefits

9 Months Ended

Sep. 30, 2021

Retirement Benefits [Abstract]

Retirement Benefits

RETIREMENT BENEFITS

The Southern Company system has a qualified defined benefit, trusteed, pension plan covering substantially all employees, with the exception of employees at PowerSecure. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2021. The Southern Company system also provides certain non-qualified defined benefits for a select group of management and highly compensated employees, which are funded on a cash basis. In addition, the Southern Company system provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The traditional electric operating companies fund other postretirement trusts to the extent required by their respective regulatory commissions. Southern Company Gas has a separate unfunded supplemental retirement health care plan that provides medical care and life insurance benefits to employees of discontinued businesses.

See Note 11 to the financial statements in Item 8 of the Form 10-K for additional information.

On each Registrant's condensed statements of income, the service cost component of net periodic benefit costs is included in other operations and maintenance expenses and all other components of net periodic benefit costs are included in other income (expense), net. Components of the net periodic benefit costs for the three and nine months ended September 30, 2021 and 2020 are presented in the following tables.

	Southern Company		Alabama Power		Georgia Power		Mississippi Power		Southern Power		Southern Company Gas
	(in millions)
Three Months Ended September 30, 2021
Pension Plans
Service cost	$	109	$	26	$	28	$	4	$	2	$	10
Interest cost	87		20		26		4		2		6
Expected return on plan assets	(298)		(72)		(94)		(14)		(4)		(21)
Amortization:
Prior service costs	—		—		—		—		—		(1)
Regulatory asset	—		—		—		—		—		3
Net (gain)/loss	78		21		25		4		1		3
Net periodic pension cost (income)	$	(24)	$	(5)	$	(15)	$	(2)	$	1	$	—
Postretirement Benefits
Service cost	$	6	$	2	$	2	$	1	$	1	$	—
Interest cost	9		2		3		—		—		1
Expected return on plan assets	(19)		(8)		(7)		(1)		—		(2)
Amortization:
Regulatory asset	—		—		—		—		—		2
Net (gain)/loss	1		—		1		—		—		(1)
Net periodic postretirement benefit cost (income)	$	(3)	$	(4)	$	(1)	$	—	$	1	$	—
Nine Months Ended September 30, 2021
Pension Plans
Service cost	$	326	$	77	$	84	$	13	$	7	$	28
Interest cost	260		61		78		12		4		18
Expected return on plan assets	(893)		(215)		(282)		(41)		(11)		(64)
Amortization:
Prior service costs	—		—		1		—		—		(2)
Regulatory asset	—		—		—		—		—		11
Net (gain)/loss	235		62		75		11		3		9
Net periodic pension cost (income)	$	(72)	$	(15)	$	(44)	$	(5)	$	3	$	—
Postretirement Benefits
Service cost	$	18	$	5	$	5	$	1	$	1	$	1
Interest cost	26		6		9		1		—		3
Expected return on plan assets	(57)		(22)		(20)		(2)		—		(6)
Amortization:
Prior service costs	(1)		—		—		—		—		—
Regulatory asset	—		—		—		—		—		5
Net (gain)/loss	3		—		2		—		—		(2)
Net periodic postretirement benefit cost (income)	$	(11)	$	(11)	$	(4)	$	—	$	1	$	1

	Southern Company		Alabama Power		Georgia Power		Mississippi Power		Southern Power		Southern Company Gas
	(in millions)
Three Months Ended September 30, 2020
Pension Plans
Service cost	$	94	$	23	$	24	$	3	$	2	$	8
Interest cost	108		25		33		5		1		8
Expected return on plan assets	(274)		(66)		(87)		(13)		(4)		(20)
Amortization:
Prior service costs	—		1		—		—		—		(1)
Regulatory asset	—		—		—		—		—		4
Net (gain)/loss	67		17		22		4		1		2
Net periodic pension cost (income)	$	(5)	$	—	$	(8)	$	(1)	$	—	$	1
Postretirement Benefits
Service cost	$	6	$	1	$	2	$	(1)	$	1	$	—
Interest cost	13		4		5		1		—		2
Expected return on plan assets	(18)		(7)		(7)		—		—		(2)
Amortization:
Prior service costs	—		—		(1)		—		—		—
Regulatory asset	—		—		—		—		—		2
Net (gain)/loss	1		—		1		—		—		(1)
Net periodic postretirement benefit cost (income)	$	2	$	(2)	$	—	$	—	$	1	$	1
Nine Months Ended September 30, 2020
Pension Plans
Service cost	$	282	$	67	$	72	$	11	$	6	$	24
Interest cost	324		75		100		15		4		23
Expected return on plan assets	(824)		(198)		(261)		(38)		(10)		(59)
Amortization:
Prior service costs	1		1		1		—		—		(2)
Regulatory asset	—		—		—		—		—		12
Net (gain)/loss	201		53		65		10		2		7
Net periodic pension cost (income)	$	(16)	$	(2)	$	(23)	$	(2)	$	2	$	5
Postretirement Benefits
Service cost	$	17	$	4	$	5	$	—	$	1	$	1
Interest cost	40		10		15		2		—		5
Expected return on plan assets	(54)		(21)		(20)		(1)		—		(5)
Amortization:
Prior service costs	(1)		—		(1)		—		—		—
Regulatory asset	—		—		—		—		—		5
Net (gain)/loss	2		—		2		—		—		(2)
Net periodic postretirement benefit cost (income)	$	4	$	(7)	$	1	$	1	$	1	$	4