Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2019

Fair Value Disclosures [Abstract]

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 March 31, 2019, and December 31, 2018:

		March 31, 2019									December 31, 2018
		Level 1		Level 2		Level 3		Total			Level 1		Level 2		Level 3		Total
Assets:
Ameren
	Derivative assets – commodity contracts(a):
	Fuel oils	$	2	$	—	$	7	$	9		$	1	$	—	$	7	$	8
	Natural gas	—		3		3		6			—		2		1		3
	Power	—		—		2		2			—		1		3		4
	Total derivative assets – commodity contracts	$	2	$	3	$	12	$	17		$	1	$	3	$	11	$	15
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	488	$	—	$	—	$	488		$	427	$	—	$	—	$	427
	Debt securities:
	U.S. Treasury and agency securities	—		151		—		151			—		148		—		148
	Corporate bonds	—		76		—		76			—		72		—		72
	Other	—		33		—		33			—		32		—		32
	Total nuclear decommissioning trust fund	$	488	$	260	$	—	$	748	(b)	$	427	$	252	$	—	$	679	(b)
	Total Ameren	$	490	$	263	$	12	$	765		$	428	$	255	$	11	$	694
Ameren Missouri
	Derivative assets – commodity contracts(a):
	Fuel oils	$	2	$	—	$	7	$	9		$	1	$	—	$	7	$	8
	Power	—		—		2		2			—		1		3		4
	Total derivative assets – commodity contracts	$	2	$	—	$	9	$	11		$	1	$	1	$	10	$	12
	Nuclear decommissioning trust fund:
	Equity securities:
	U.S. large capitalization	$	488	$	—	$	—	$	488		$	427	$	—	$	—	$	427
	Debt securities:
	U.S. Treasury and agency securities	—		151		—		151			—		148		—		148
	Corporate bonds	—		76		—		76			—		72		—		72
	Other	—		33		—		33			—		32		—		32
	Total nuclear decommissioning trust fund	$	488	$	260	$	—	$	748	(b)	$	427	$	252	$	—	$	679	(b)
	Total Ameren Missouri	$	490	$	260	$	9	$	759		$	428	$	253	$	10	$	691
Ameren Illinois
	Derivative assets – commodity contracts(a):
	Natural gas	$	—	$	3	$	3	$	6		$	—	$	2	$	1	$	3
Liabilities:
Ameren
	Derivative liabilities – commodity contracts(a):
	Fuel oils	$	1	$	—	$	6	$	7		$	2	$	—	$	11	$	13
	Natural gas	—		10		3		13			—		15		4		19
	Power	—		—		186		186			—		1		186		187
	Total Ameren	$	1	$	10	$	195	$	206		$	2	$	16	$	201	$	219
Ameren Missouri
	Derivative liabilities – commodity contracts(a):
	Fuel oils	$	1	$	—	$	6	$	7		$	2	$	—	$	11	$	13
	Natural gas	—		3		—		3			—		5		—		5
	Power	—		—		2		2			—		1		3		4
	Total Ameren Missouri	$	1	$	3	$	8	$	12		$	2	$	6	$	14	$	22
Ameren Illinois
	Derivative liabilities – commodity contracts(a):
	Natural gas	$	—	$	7	$	3	$	10		$	—	$	10	$	4	$	14
	Power	—		—		184		184			—		—		183		183
	Total Ameren Illinois	$	—	$	7	$	187	$	194		$	—	$	10	$	187	$	197

(a) The derivative asset and liability balances are presented net of registrant and counterparty credit considerations.

(b) Balance excludes $6 million and $5 million of cash and cash equivalents, receivables, payables, and accrued income, net, for March 31, 2019, and December 31, 2018, respectively.

Schedule Of Changes In The Fair Value Of Financial Assets And Liabilities Classified As Level Three 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 three months ended March 31, 2019 and 2018:

	2019								2018
	Ameren Missouri		Ameren Illinois			Ameren			Ameren Missouri			Ameren Illinois			Ameren
Beginning balance at January 1	$	—	$	(183	)	$	(183	)	$	7		$	(195	)	$	(188	)
Realized and unrealized losses included in regulatory assets/liabilities	—		(4		)	(4		)	(2		)	1			(1		)
Settlements	—		3			3			(1		)	3			2
Ending balance at March 31	$	—	$	(184	)	$	(184	)	$	4		$	(191	)	$	(187	)
Change in unrealized losses related to assets/liabilities held at March 31	$	—	$	(4	)	$	(4	)	$	(1	)	$	1		$	—

Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques

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 March 31, 2019, and December 31, 2018:

			Fair Value(a)						Weighted Average
	Commodity		Assets		Liabilities	Valuation Technique(s)	Unobservable Input	Range
2019	Power(b)	$	2	$	(186)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)(c)	24 – 38	28
							Nodal basis ($/MWh)(c)	(9) – 0	(2)
						Fundamental energy production model	Estimated future natural gas prices ($/mmbtu)(c)	3 – 4	3
2018	Power(b)	$	3	$	(186)	Discounted cash flow	Average forward peak and off-peak pricing – forwards/swaps ($/MWh)(c)	23 – 39	28
							Nodal basis ($/MWh)(c)	(9) – 0	(2)
						Fundamental energy production model	Estimated future natural gas prices ($/mmbtu)(c)	3 – 4	3

(a) The derivative asset and liability balances are presented net of registrant and counterparty credit considerations.

(b) Power valuations use visible third-party pricing evaluated by month for peak and off-peak demand through 2022. Valuations beyond 2022 use fundamentally modeled pricing by month for peak and off-peak demand.

(c) Generally, significant increases (decreases) in this input in isolation would result in a significantly higher (lower) fair value measurement.

Schedule of Financial Assets and Liabilities

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 March 31, 2019, and December 31, 2018:

	March 31, 2019
	Carrying Amount			Fair Value
				Level 1		Level 2		Level 3			Total
Ameren:
Cash, cash equivalents, and restricted cash	$	118		$	118	$	—	$	—		$	118
Investments in held-to-maturity debt securities(a)	270			—		270		—			270
Short-term debt	799			—		799		—			799
Long-term debt (including current portion)(a)	8,557		(b)	—		8,623		447		(c)	9,070
Ameren Missouri:
Cash, cash equivalents, and restricted cash	$	12		$	12	$	—	$	—		$	12
Investments in held-to-maturity debt securities(a)	270			—		270		—			270
Short-term debt	55			—		55		—			55
Long-term debt (including current portion)(a)	4,116		(b)	—		4,404		—			4,404
Ameren Illinois:
Cash, cash equivalents, and restricted cash	$	93		$	93	$	—	$	—		$	93
Short-term debt	126			—		126		—			126
Long-term debt (including current portion)	3,296		(b)	—		3,515		—			3,515
	December 31, 2018
Ameren:
Cash, cash equivalents, and restricted cash	$	107		$	107	$	—	$	—		$	107
Investments in held-to-maturity debt securities(a)	270			—		270		—			270
Short-term debt	597			—		597		—			597
Long-term debt (including current portion)(a)	8,439		(b)	—		8,240		429		(c)	8,669
Ameren Missouri:
Cash, cash equivalents, and restricted cash	$	8		$	8	$	—	$	—		$	8
Investments in held-to-maturity debt securities(a)	270			—		270		—			270
Short-term debt	55			—		55		—			55
Long-term debt (including current portion)(a)	3,998		(b)	—		4,156		—			4,156
Ameren Illinois:
Cash, cash equivalents, and restricted cash	$	80		$	80	$	—	$	—		$	80
Short-term debt	72			—		72		—			72
Long-term debt (including current portion)	3,296		(b)	—		3,391		—			3,391

(a) Ameren and Ameren Missouri have investments in industrial development revenue bonds, classified as held-to-maturity and recorded in “Other Assets,” that are equal to the finance obligations for the Peno Creek and Audrain CT energy centers. As of March 31, 2019, and December 31, 2018, the carrying amount of both the investments in industrial development revenue bonds and the finance obligations approximated fair value.

(b) Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $62 million, $25 million, and $32 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of March 31, 2019. Included unamortized debt issuance costs, which were excluded from the fair value measurement, of $58 million, $22 million, and $31 million for Ameren, Ameren Missouri, and Ameren Illinois, respectively, as of December 31, 2018.

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