Retirement Benefits (Tables)

6 Months Ended

Jun. 30, 2020

Retirement Benefits [Abstract]

Components Of Net Periodic Benefit Cost

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, 2020 and 2019:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2020		2019		2020		2019		2020		2019		2020		2019
Service cost(a)	$	28	$	22	$	55	$	44	$	6	$	5	$	10	$	9
Non-service cost components:
Interest cost	44		46		87		93		9		10		19		21
Expected return on plan assets	(72)		(69)		(145)		(138)		(20)		(19)		(40)		(38)
Amortization of:
Prior service benefit	(1)		—		(1)		—		(1)		(2)		(2)		(3)
Actuarial loss (gain)	16		7		30		13		(2)		(3)		(4)		(7)
Total non-service cost components(b)	$	(13)	$	(16)	$	(29)	$	(32)	$	(14)	$	(14)	$	(27)	$	(27)
Net periodic benefit cost (income)	$	15	$	6	$	26	$	12	$	(8)	$	(9)	$	(17)	$	(18)

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

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

Summary Of Benefit Plan Costs Incurred

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, 2020 and 2019:

	Pension Benefits								Postretirement Benefits
	Three Months				Six Months				Three Months				Six Months
	2020		2019		2020		2019		2020		2019		2020		2019
Ameren Missouri(a)	$	7	$	1	$	11	$	2	$	(1)	$	(1)	$	(2)	$	(3)
Ameren Illinois	9		5		16		10		(8)		(8)		(16)		(15)
Other	(1)		—		(1)		—		1		—		1		—
Ameren(a)	$	15	$	6	$	26	$	12	$	(8)	$	(9)	$	(17)	$	(18)

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