Callaway Energy Center (Tables)

12 Months Ended

Dec. 31, 2020

Nuclear Waste Matters [Abstract]

Proceeds From Sale Of Investments In Nuclear Decommissioning Trust Fund And Gross Realized Gains And Losses

The following table presents proceeds from the sale and maturities of investments in Ameren Missouri’s nuclear decommissioning trust fund and the gross realized gains and losses resulting from those sales for the years ended December 31, 2020, 2019, and 2018:

	2020		2019		2018
Proceeds from sales and maturities	$	183	$	260	$	299
Gross realized gains	10		10		18
Gross realized losses	3		2		5

Fair Value Of Securities In Nuclear Decommissioning Trust Fund

The following table presents the cost and fair value of investments in debt and equity securities in Ameren’s and Ameren Missouri’s nuclear decommissioning trust fund at December 31, 2020 and December 31, 2019:

Security Type	Cost		Gross Unrealized Gain		Gross Unrealized Loss		Fair Value
2020
Debt securities	$	272	$	25	$	—	$	297
Equity securities	198		491		9		680
Cash and cash equivalents	4		—		—		4
Other(a)	1		—		—		1
Total	$	475	$	516	$	9	$	982
2019
Debt securities	$	262	$	11	$	—	$	273
Equity securities	183		393		7		569
Cash and cash equivalents	26		—		—		26
Other(a)	(21)		—		—		(21)
Total	$	450	$	404	$	7	$	847

(a)Represents net receivables and payables relating to pending securities sales, interest, and securities purchases.

Fair Value Of Securities In Nuclear Decommissioning Trust Fund Classified by Contractual Maturity Date

The following table presents the costs and fair values of investments in debt securities in Ameren’s and Ameren Missouri’s nuclear decommissioning trust fund according to their contractual maturities at December 31, 2020:

	Cost		Fair Value
Less than 5 years	$	120	$	123
5 years to 10 years	69		75
Due after 10 years	83		99
Total	$	272	$	297

Schedule of Insurance Coverage

The following table presents insurance coverage at Ameren Missouri’s Callaway Energy Center at December 31, 2020:

Type and Source of Coverage	Most Recent Renewal Date	Maximum Coverages			Maximum Assessments for Single Incidents
Public liability and nuclear worker liability:
American Nuclear Insurers	January 1, 2021	$	450		$	—
Pool participation	(a)	13,348		(a)	138		(b)
		$	13,798	(c)	$	138
Property damage:
NEIL and EMANI	April 1, 2020	$	3,200	(d)	$	25	(e)
Replacement power:
NEIL	April 1, 2020	$	490	(f)	$	7	(e)

(a)Provided through mandatory participation in an industrywide retrospective premium assessment program. The maximum coverage available is dependent on the number of United States commercial reactors participating in the program.

(b)Retrospective premium under the Price-Anderson Act. This is subject to retrospective assessment with respect to a covered loss in excess of $450 million in the event of an incident at any licensed United States commercial reactor, payable at $21 million per year.

(c)Limit of liability for each incident under the Price-Anderson liability provisions of the Atomic Energy Act of 1954, as amended. This limit is subject to change to account for the effects of inflation and changes in the number of licensed power reactors.

(d)NEIL provides $2.7 billion in property damage, stabilization, decontamination, and premature decommissioning insurance for radiation events and $2.3 billion in property damage insurance for nonradiation events. EMANI provides $490 million in property damage insurance for both radiation and nonradiation events.

(e)All NEIL-insured plants could be subject to assessments should losses exceed the accumulated funds from NEIL.

(f)Provides replacement power cost insurance in the event of a prolonged accidental outage. Weekly indemnity up to $4.5 million for 52 weeks, which commences after the first 12 weeks of an outage, plus up to $3.6 million per week for a minimum of 71 weeks thereafter for a total not exceeding the policy limit of $490 million. Nonradiation events are limited to $328 million.