Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Schedule Of Fair Value Hierarchy Of Assets And Liabilities Measured At Fair Value On Recurring Basis

The following table sets forth, by level within the fair value hierarchy, our assets and liabilities measured at fair value on a recurring basis as of December 31, 2023 and 2022:


		December 31, 2023									December 31, 2022
		Level 1		Level 2		Level 3		Total			Level 1		Level 2		Level 3		Total
Assets:
Ameren Missouri
	Derivative assets – commodity contracts:
	Fuel oils	$	2	$	—	$	—	$	2		$	16	$	—	$	—	$	16
	Natural gas	—		3		—		3			1		15		—		16
	Power	—		—		5		5			—		—		14		14
	Uranium	—		—		9		9			—		—		3		3
	Total derivative assets – commodity contracts	$	2	$	3	$	14	$	19		$	17	$	15	$	17	$	49
	Nuclear decommissioning trust fund:

	Equity securities:
	U.S. large capitalization	$	787	$	—	$	—	$	787		$	618	$	—	$	—	$	618
	Debt securities:
	U.S. Treasury and agency securities	—		150		—		150			—		137		—		137
	Corporate bonds	—		136		—		136			—		122		—		122


	Other	—		68		—		68			—		70		—		70
	Total nuclear decommissioning trust fund	$	787	$	354	$	—	$	1,141	(a)	$	618	$	329	$	—	$	947	(a)
	Total Ameren Missouri	$	789	$	357	$	14	$	1,160		$	635	$	344	$	17	$	996
Ameren Illinois
	Derivative assets – commodity contracts:
	Natural gas	$	—	$	1	$	2	$	3		$	1	$	28	$	5	$	34
	Power	—		—		—		—			—		—		6		6
	Total Ameren Illinois	$	—	$	1	$	2	$	3		$	1	$	28	$	11	$	40
Ameren
	Derivative assets – commodity contracts(b)	$	2	$	4	$	16	$	22		$	18	$	43	$	28	$	89
	Nuclear decommissioning trust fund(c)	787		354		—		1,141		(a)	618		329		—		947		(a)
	Total Ameren	$	789	$	358	$	16	$	1,163		$	636	$	372	$	28	$	1,036
Liabilities:
Ameren Missouri
	Derivative liabilities – commodity contracts:
	Fuel oils	$	2	$	—	$	—	$	2		$	—	$	—	$	—	$	—
	Natural gas	$	—	$	19	$	3	$	22		$	—	$	6	$	3	$	9
	Power	—		—		1		1			57		—		2		59

	Total Ameren Missouri	$	2	$	19	$	4	$	25		$	57	$	6	$	5	$	68
Ameren Illinois
	Derivative liabilities – commodity contracts:
	Natural gas	$	4	$	60	$	11	$	75		$	—	$	19	$	10	$	29
	Power	—		—		68		68			—		—		39		39
	Total Ameren Illinois	$	4	$	60	$	79	$	143		$	—	$	19	$	49	$	68
Ameren
	Derivative liabilities – commodity contracts(b)	$	6	$	79	$	83	$	168		$	57	$	25	$	54	$	136

(a)Balance excludes $9 million and $11 million of cash and cash equivalents, receivables, payables, and accrued income, net for December 31, 2023 and 2022, respectively.

(b)See the Ameren Missouri and Ameren Illinois sections of the table for a breakout of the fair value of Ameren’s derivative assets and liabilities by type of commodity.

(c)See the Ameren Missouri section of the table for a breakout of Ameren’s nuclear decommissioning trust fund by investment type.

Schedule Of Changes In The Fair Value Of Financial Assets And Liabilities Classified As Level 3 In The Fair Value Hierarchy

The following table presents the fair value reconciliation of Level 3 power derivative contract assets and liabilities measured at fair value on a recurring basis for the years ended December 31, 2023 and 2022:


	2023						2022
	Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois		Ameren





















Beginning balance at January 1	$	12	$	(33)	$	(21)	$	(15)	$	(117)	$	(132)
Realized and unrealized gains (losses) included in regulatory assets/liabilities	1		(48)		(47)		(45)		92		47


Settlements	(9)		13		4		72		(8)		64


Ending balance at December 31	$	4	$	(68)	$	(64)	$	12	$	(33)	$	(21)
Change in unrealized gains (losses) related to assets/liabilities held at December 31	$	4	$	(36)	$	(32)	$	12	$	75	$	87

Fair Value Inputs, Assets and Liabilities, Quantitative Information

The following table describes the valuation techniques and significant unobservable inputs utilized for the fair value of our Level 3 power derivative contract assets and liabilities as of December 31, 2023 and 2022:


		Fair Value							Weighted Average(b)
	Commodity	Assets		Liabilities		Valuation Technique(s)	Unobservable Input(a)	Range









2023	Power(c)	$	5	$	(69)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	31 – 65	43

							Nodal basis ($/MWh)	(8) – (1)	(5)














































2022	Power(d)	$	20	$	(41)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)	38 – 89	51
							Nodal basis ($/MWh)	(10) – (1)	(4)


							Trend rate (%)	0– 1	0

(a)Generally, significant increases (decreases) in these inputs in isolation would result in a significantly higher (lower) fair value measurement.

(b)Unobservable inputs were weighted by relative fair value.

(c)Valuations use visible forward prices adjusted for nodal-to-hub basis differentials.

(d)Valuations through 2031 use visible forward prices adjusted for nodal-to-hub basis differentials. Valuations beyond 2031 use a trend rate factor and are similarly adjusted for nodal-to-hub basis differentials.

Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]

The following table sets forth, by level within the fair value hierarchy, the carrying amount and fair value of financial assets and liabilities disclosed, but not carried, at fair value as of December 31, 2023 and 2022:


	Carrying Amount			Fair Value
				Level 1		Level 2		Level 3			Total
	December 31, 2023
Ameren:
Cash, cash equivalents, and restricted cash	$	272		$	272	$	—	$	—		$	272

Short-term debt	536			—		536		—			536
Long-term debt (including current portion)	15,970		(a)	—		14,366		467		(b)	14,833
Ameren Missouri:
Cash, cash equivalents, and restricted cash	$	10		$	10	$	—	$	—		$	10


Short-term debt	170			—		170		—			170
Borrowings from money pool	306			—		306		—			306
Long-term debt (including current portion)	6,341		(a)	—		5,800		—			5,800
Ameren Illinois:
Cash, cash equivalents, and restricted cash	$	234		$	234	$	—	$	—		$	234

Short-term debt	366			—		366		—			366
Borrowings from money pool	135			—		135		—			135
Long-term debt (including current portion)	5,232		(a)	—		4,867		—			4,867
	December 31, 2022
Ameren:
Cash, cash equivalents, and restricted cash	$	216		$	216	$	—	$	—		$	216
Investments in industrial development revenue bonds(c)	240			—		240		—			240
Short-term debt	1,070			—		1,070		—			1,070
Long-term debt (including current portion)(c)	14,025		(a)	—		11,989		464		(b)	12,453
Ameren Missouri:
Cash, cash equivalents, and restricted cash	$	13		$	13	$	—	$	—		$	13

Investments in industrial development revenue bonds(c)	240			—		240		—			240
Short-term debt	329			—		329		—			329

Long-term debt (including current portion)(c)	6,086		(a)	—		5,365		—			5,365
Ameren Illinois:
Cash, cash equivalents, and restricted cash	$	191		$	191	$	—	$	—		$	191

Short-term debt	264			—		264		—			264

Long-term debt (including current portion)	4,835		(a)	—		4,320		—			4,320

(a)Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $111 million, $45 million, and $47 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2023. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $99 million, $41 million, and $44 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2022.

(b)The Level 3 fair value amount consists of ATXI’s senior unsecured notes.

(c)Ameren and Ameren Missouri had investments in industrial development revenue bonds, classified as held-to-maturity and recorded in “Investments in industrial development revenue bonds,” as of December 31, 2022, respectively, that were equal to the finance obligation for the Audrain CT energy center. As of December 31, 2022, the carrying amount of the investments in industrial development revenue bonds and the finance obligations approximated fair value. The financing obligation for the Audrain CT Energy Center was settled in January 2023. See Note 5 – Long-term Debt and Equity Financings for additional information on these agreements.