Retirement Benefits

6 Months Ended

Jun. 30, 2023

Retirement Benefits [Abstract]

RETIREMENT BENEFITS

RETIREMENT BENEFITS

The following table presents the components of the net periodic benefit cost (income) incurred for Ameren’s pension and postretirement benefit plans for the three and six months ended June 30, 2023 and 2022:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2023		2022		2023		2022		2023		2022		2023		2022
Service cost(a)	$	23	$	31	$	46	$	64	$	3	$	5	$	6	$	10
Non-service cost components:
Interest cost	56		41		111		81		12		9		23		17
Expected return on plan assets(b)	(84)		(80)		(167)		(160)		(23)		(22)		(46)		(43)
Amortization of(b):
Prior service benefit	—		—		—		—		(1)		(1)		(2)		(2)
Actuarial loss (gain)	(28)		6		(57)		12		(12)		(5)		(23)		(9)
Total non-service cost components(c)	$	(56)	$	(33)	$	(113)	$	(67)	$	(24)	$	(19)	$	(48)	$	(37)
Net periodic benefit income(d)	$	(33)	$	(2)	$	(67)	$	(3)	$	(21)	$	(14)	$	(42)	$	(27)

(a)Service cost, net of capitalization, is reflected in “Operating Expenses – Other operations and maintenance” on Ameren’s statement of income.

(b)Prior service benefit is amortized on a straight-line basis over the average future service of active participants benefiting under a plan amendment. Net actuarial gains or losses related to the net benefit obligation subject to amortization are amortized on a straight-line basis over 10 years. The difference between the actual and expected return on plan assets is amortized over 4 years.

(c)Non-service cost components are reflected in “Other Income, Net” on Ameren’s consolidated statement of income. See Note 5 – Other Income, Net for additional information.

(d)Does not include the impact of the tracker for the difference between the level of pension and postretirement benefit costs (income) incurred by Ameren Missouri under GAAP and the level of such costs included in rates.

Ameren Missouri and Ameren Illinois are responsible for their respective share of Ameren’s pension and other postretirement costs. The following table presents the respective share of net periodic pension and other postretirement benefit costs (income) incurred for the three and six months ended June 30, 2023 and 2022:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2023		2022		2023		2022		2023		2022		2023		2022
Ameren Missouri(a)	$	(17)	$	(1)	$	(35)	$	(2)	$	(7)	$	(4)	$	(15)	$	(7)
Ameren Illinois	(13)		—		(27)		1		(14)		(10)		(27)		(20)
Other	(3)		(1)		(5)		(2)		—		—		—		—
Ameren(a)	$	(33)	$	(2)	$	(67)	$	(3)	$	(21)	$	(14)	$	(42)	$	(27)

(a)Does not include the impact of the tracker for the difference between the level of pension and postretirement benefit costs (income) incurred by Ameren Missouri under GAAP and the level of such costs included in rates.