Rate And Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2019

Public Utilities, General Disclosures [Abstract]

Schedule of Wind Generation Facilities

The following table provides information with respect to each build-transfer agreement:

	Up-to 400-Megawatt Facility	Up-to 300-Megawatt Facility
Build-transfer agreement date	April 2018	May 2019
Wind facility developer	Terra-Gen, LLC	Invenergy Renewables, LLC
Location	Northeastern Missouri	Northwestern Missouri
Status of certificate of convenience and necessity from the MoPSC	Approved October 2018	Approved August 2019
Status of final interconnection costs	Received July 2019	Received July 2019
Status of RTO transmission interconnection agreement	Executed August 2019	Executed October 2019
Status of FERC approval	Received December 2018	Received October 2019
Expected completion date	By the end of 2020	By the end of 2020

Schedule Of Regulatory Assets And Liabilities

The following table presents our regulatory assets and regulatory liabilities at December 31, 2019 and 2018:

	2019									2018
	Ameren Missouri			Ameren Illinois			Ameren			Ameren Missouri			Ameren Illinois			Ameren
Regulatory assets:
Under-recovered Illinois electric power costs(a)	$	—		$	4		$	4		$	—		$	—		$	—
Under-recovered PGA(a)	—			—			—			—			7			7
MTM derivative losses(b)	12			242			254			19			197			216
IEIMA revenue requirement reconciliation adjustment(c)(d)	—			17			17			—			70			70
FERC revenue requirement reconciliation adjustment(e)	—			1			16			—			16			30
Pension and postretirement benefit costs(f)	7			26			33			103			149			252
Income taxes(g)	114			61			177			119			68			185
Callaway costs(d)(h)	18			—			18			22			—			22
Unamortized loss on reacquired debt(i)	55			31			86			58			40			98
Environmental cost riders(j)	—			127			127			—			148			148
Storm costs(d)(k)	—			7			7			—			13			13
Workers’ compensation claims(l)	4			7			11			4			7			11
Construction accounting for pollution control equipment(d)(m)	15			—			15			16			—			16
Solar rebate program(n)	5			—			5			14			—			14
PISA(o)(d)	41			—			41			1			—			1
RESRAM(p)	9			—			9			—			—			—
FEJA energy-efficiency rider(d)(q)	—			211			211			—			136			136
Other	13			17			30			24			18			42
Total regulatory assets	$	293		$	751		$	1,061		$	380		$	869		$	1,261
Less: current regulatory assets	(8		)	(57		)	(69		)	(14		)	(110		)	(134		)
Noncurrent regulatory assets	$	285		$	694		$	992		$	366		$	759		$	1,127
Regulatory liabilities:
Over-recovered FAC(r)	$	39		$	—		$	39		$	34		$	—		$	34
Over-recovered Illinois electric power costs(a)	—			11			11			—			12			12
Over-recovered PGA(a)	8			14			22			7			3			10
Over-recovered VBA rider(s)	—			8			8			—			8			8
MTM derivative gains(b)	18			3			21			5			3			8
IEIMA revenue requirement reconciliation adjustment(c)	—			18			18			—			—			—
FERC revenue requirement reconciliation adjustment(e)	—			37			38			—			17			19
MEEIA energy-efficiency rider(t)	3			—			3			19			—			19
Estimated refund for FERC complaint cases(u)	—			23			40			—			26			44
Income taxes(g)	1,428			813			2,326			1,484			843			2,413
Cost of removal(v)	1,041			827			1,884			1,027			774			1,811
AROs(w)	303			—			303			175			—			175
Pension and postretirement benefit costs tracker(x)	72			—			72			43			—			43
Renewable energy credits and zero emission credits(y)	—			155			155			—			102			102
Excess income taxes collected in 2018(z)	60			—			60			60			—			60
Other	27			24			51			13			15			28
Total regulatory liabilities	$	2,999		$	1,933		$	5,051		$	2,867		$	1,803		$	4,786
Less: current regulatory liabilities	(62		)	(84		)	(164		)	(68		)	(62		)	$	(149	)
Noncurrent regulatory liabilities	$	2,937		$	1,849		$	4,887		$	2,799		$	1,741		$	4,637

(a) Under-recovered or over-recovered costs from utility customers. Amounts will be recovered from, or refunded to, customers within one year of the deferral.

(b) Deferral of commodity-related derivative MTM losses or gains. See Note 7 – Derivative Financial Instruments for additional information.

(c) The difference between Ameren Illinois’ electric distribution service annual revenue requirement calculated under the performance-based formula ratemaking framework and the revenue requirement included in customer rates for that year. Any under-recovery or over-recovery will be recovered from, or refunded to, customers with interest within two years.

(d) These assets earn a return at the applicable WACC.

(e) Ameren Illinois’ and ATXI’s annual revenue requirement reconciliation calculated pursuant to the FERC’s electric transmission formula ratemaking framework. Any under-recovery or over-recovery will be recovered from, or refunded to, customers within two years.

(f) These costs are being amortized in proportion to the recognition of prior service costs (credits) and actuarial losses (gains) attributable to Ameren’s pension plan and postretirement benefit plans. See Note 10 – Retirement Benefits for additional information.

(g) The regulatory assets represent amounts that will be recovered from customers for deferred income taxes related to the equity component of allowance for funds used during construction and the effects of tax rate changes. The regulatory liabilities represent amounts that will be refunded to customers for deferred income taxes related to depreciation differences, other tax liabilities, and the unamortized portion of investment tax credits recorded at rates in excess of current statutory rates. Amounts associated with the equity component of allowance for funds used during construction, and the unamortized portion of investment tax credits will be amortized over the expected life of the related assets. For net regulatory liabilities related to deferred income taxes recorded at rates other than the current statutory rate, the weighted-average remaining amortization periods at Ameren, Ameren Missouri, and Ameren Illinois are 34, 26, and 43 years.

(h) Ameren Missouri’s Callaway Energy Center operations and maintenance expenses, property taxes, and carrying costs incurred between the plant in-service date and the date the plant was reflected in rates. These costs are being amortized over the original remaining life of the energy center.

(i) Losses related to reacquired debt. These amounts are being amortized over the lives of the related new debt issuances or the original lives of the old debt issuances if no new debt was issued.

(j) The recoverable portion of accrued environmental site liabilities that will be collected from electric and natural gas customers through ICC-approved cost recovery riders. The period of recovery will depend on the timing of remediation expenditures. See Note 14 – Commitments and Contingencies for additional information.

(k) Storm costs from 2016 and 2018 deferred in accordance with the IEIMA. These costs are being amortized over five-year periods beginning in the year the storm occurred.

(l) The period of recovery will depend on the timing of actual expenditures.

(m) The MoPSC’s May 2010 electric rate order allowed Ameren Missouri to record an allowance for funds used during construction for pollution control equipment at its Sioux Energy Center until the cost of that equipment was included in customer rates beginning in 2011. These costs are being amortized over the expected life of the Sioux Energy Center, currently through 2033.

(n) Costs associated with Ameren Missouri’s solar rebate program. The amortization period for these assets will be determined in a future electric service regulatory rate review.

(o) Under the PISA, Ameren Missouri is permitted to defer and recover 85% of the depreciation expense on certain property, plant, and equipment placed in service after September 1, 2018, and not included in base rates. Accumulated PISA deferrals are added to rate base prospectively and amortized over a period of 20 years following a regulatory rate review.

(p) Costs associated with Ameren Missouri’s compliance with the state of Missouri’s renewable energy standard. Costs incurred over a twelve-month period beginning each August are amortized over a twelve-month period beginning February the following year.

(q) The electric energy-efficiency investments are being amortized over their weighted-average useful lives beginning in the period in which they were made, with current remaining amortization periods ranging from 7 to 12 years.

(r) Under-recovered or over-recovered fuel costs to be recovered or refunded through the FAC. Specific accumulation periods aggregate the under-recovered or over-recovered costs over four months, any related adjustments that occur over the following four months, and the recovery from, or refund to, customers that occurs over the next eight months.

(s) Under-recovered or over-recovered natural gas revenue caused by sales volume deviations from weather normalized sales approved by the ICC in rate regulatory reviews. Each year’s amount will be recovered from or refunded to customers from April through December of the following year.

(t) The MEEIA rider allows Ameren Missouri to collect from, or refund to, customers any annual difference in the actual amounts incurred and the amounts collected from customers for the MEEIA program costs, lost electric margins, and the performance incentive. Under the MEEIA rider, collections from or refunds to customers occur one year after the program costs, and lost electric margins are incurred or any performance incentive are earned.

(u) The 2019 balances represent the estimated refunds to transmission customers related to the November 2019 FERC order in the November 2013 FERC complaint case. The 2018 balances represent the estimated refunds to transmission customers related to the February 2015 FERC complaint case, which was dismissed in the November 2019 order. See further discussion of the FERC ROE complaint cases above.

(v) Estimated funds collected from customers to pay for the future removal cost of property, plant, and equipment retired from service, net of salvage.

(w) Recoverable or refundable removal costs for AROs, including net realized and unrealized gains and losses related to the nuclear decommissioning trust fund investments. See Note 1 – Summary of Significant Accounting Policies – Asset Retirement Obligations.

(x) A regulatory recovery mechanism for the difference between the level of pension and postretirement benefit costs incurred by Ameren Missouri and the level of such costs included in customer rates. The period of refund varies based on MoPSC approval in a regulatory rate review. For costs incurred prior to December 2016, the weighted-average remaining amortization period is three years. For costs incurred after December 2016, the amortization period will be determined in the current electric service regulatory rate review.

(y) Funds collected for the purchase of renewable energy credits and zero emission credits through IPA procurements. The balance will be amortized as the credits are purchased.

(z)

The excess amount collected in rates related to the TCJA from January 1, 2018, through July 31, 2018. The regulatory liability will be reflected in customer rates over a period of time to be determined by the MoPSC in the current electric service regulatory rate review.