Supplemental Information (Tables)

9 Months Ended

Sep. 30, 2020

Supplemental Information [Abstract]

Schedule of Cash and Cash Equivalents Including Restricted Cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets and the statements of cash flows as of September 30, 2020, and December 31, 2019:

	September 30, 2020						December 31, 2019
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
Cash and cash equivalents	$	6	$	—	$	—	$	16	$	9	$	—
Restricted cash included in “Other current assets”	14		4		5		14		4		5
Restricted cash included in “Other assets”	142		—		142		120		—		120
Restricted cash included in “Nuclear decommissioning trust fund”	6		6		—		26		26		—
Total cash, cash equivalents, and restricted cash	$	168	$	10	$	147	$	176	$	39	$	125

Schedule of Accounts, Notes, Loans and Financing Receivable

The following table provides a reconciliation of the beginning and ending amount of the allowance for doubtful accounts for the three and nine months ended September 30, 2020 and 2019:

	Three Months				Nine Months
	2020		2019		2020		2019
Ameren:
Beginning of period	$	25	$	19	$	17	$	18
Bad debt expense	21		14		31		22
Net write-offs	(2)		(14)		(4)		(21)
End of period	$	44	$	19	$	44	$	19
Ameren Missouri:
Beginning of period	$	9	$	7	$	7	$	7
Bad debt expense	5		3		9		6
Net write-offs	—		(2)		(2)		(5)
End of period	$	14	$	8	$	14	$	8
Ameren Illinois:(a)
Beginning of Period	$	16	$	12	$	10	$	11
Bad debt expense	16		11		22		16
Net write-offs	(2)		(12)		(2)		(16)
End of Period	$	30	$	11	$	30	$	11

(a)Ameren Illinois has rate-adjustment mechanisms that allow it to recover the difference between its actual net bad debt write-offs under GAAP, including those associated with receivables purchased from alternative retail electric suppliers, and the amount of net bad debt write-offs included in its base rates. In 2020, the rate-adjustment mechanism for electric distribution allows for recovery of bad debt expense recognized under GAAP. See Note 2 – Rate and Regulatory Matters for additional information.

Schedule of Cash Flow, Supplemental Disclosures

Supplemental Cash Flow Information

The following table provides noncash financing and investing activity excluded from the statements of cash flows for the nine months ended September 30, 2020 and 2019:

	September 30, 2020						September 30, 2019
	Ameren		Ameren Missouri		Ameren Illinois		Ameren		Ameren Missouri		Ameren Illinois
Investing
Exchange of bond investments for the extinguishment of senior unsecured notes	$	—	$	—	$	—	$	17	$	—	$	17
Accrued capital expenditures	311		115		191		273		138		128
Net realized and unrealized gain (loss) – nuclear decommissioning trust fund	43		43		—		100		100		—
Financing
Exchange of bond investments for the extinguishment of senior unsecured notes	$	—	$	—	$	—	$	(17)	$	—	$	(17)
Issuance of common stock for stock-based compensation	38		—		—		54		—		—

Asset Retirement Obligation Disclosure

The following table provides a reconciliation of the beginning and ending carrying amount of AROs for the nine months ended September 30, 2020:

	Ameren Missouri			Ameren Illinois			Ameren
Balance at December 31, 2019	$	687		$	4	(a)	$	691	(b)
Liabilities settled	(42)			—			(42)
Accretion	21		(c)	1		(c)	22		(c)
Change in estimates	57		(d)	—			57		(d)
Balance at September 30, 2020	$	723		$	5	(a)	$	728	(b)

(a)Included in “Other deferred credits and liabilities” on the balance sheet.

(b)Balance included $53 million in “Other current liabilities” on the balance sheet as of both December 31, 2019, and September 30, 2020.

(c)Accretion expense attributable to Ameren Missouri and Ameren Illinois was recorded as a decrease to regulatory liabilities and an increase to regulatory assets, respectively.

(d)Ameren Missouri changed its fair value estimate primarily due to an update to the decommissioning of the Callaway Energy Center to reflect the cost study and funding analysis filed with the MoPSC in November 2020 and an increase in the cost estimate for closure of certain CCR storage facilities.

Schedule of excise taxes

The following table presents the excise taxes recorded on a gross basis in “Operating Revenues – Electric,” “Operating Revenues – Natural gas” and “Operating Expenses – Taxes other than income taxes” on the statements of income for the three and nine months ended September 30, 2020 and 2019:

	Three Months				Nine Months
	2020		2019		2020		2019
Ameren Missouri	$	45	$	49	$	111	$	118
Ameren Illinois	26		27		87		91
Ameren	$	71	$	76	$	198	$	209

Schedule of Earnings Per Share, Basic and Diluted

The following table reconciles the basic weighted-average number of common shares outstanding to the diluted weighted-average number of common shares outstanding for the three and nine months ended September 30, 2020 and 2019:

	Three Months		Nine Months
	2020	2019	2020	2019
Weighted-average Common Shares Outstanding – Basic	247.1	245.9	246.8	245.5
Assumed settlement of performance share units and restricted stock units	1.5	1.4	1.2	1.4
Dilutive effect of forward sale agreement	0.6	0.2	0.4	0.1
Weighted-average Common Shares Outstanding – Diluted(a)	249.2	247.5	248.4	247.0

(a)There were no potentially dilutive securities excluded from the earnings per diluted share calculations for the three and nine months ended September 30, 2020 and 2019.