Rate And Regulatory Matters	9 Months Ended
Sep. 30, 2015
Public Utilities, General Disclosures [Abstract]
RATE AND REGULATORY MATTERS	RATE AND REGULATORY MATTERS Below is a summary of updates to significant regulatory proceedings and related lawsuits. See also Note 2 - Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K. We are unable to predict the ultimate outcome of these matters, the timing of the final decisions of the various agencies and courts, or the impact on our results of operations, financial position, or liquidity. Missouri 2015 Electric Rate Order In April 2015, the MoPSC issued an order approving an increase in Ameren Missouri’s annual revenues for electric service of $122 million, including $109 million related to the increase in net energy costs above those included in base rates previously authorized by the MoPSC. The revenue increase was based on a 9.53% return on common equity, a capital structure composed of 51.8% common equity, and a rate base of $7.0 billion to reflect investments through December 31, 2014. Rate changes consistent with the order became effective on May 30, 2015. The order approved Ameren Missouri’s request for continued use of the FAC; however, it changed the FAC to exclude all transmission revenues and substantially all transmission charges. In addition, the order did not approve the continued use of the regulatory tracking mechanisms for storm costs and vegetation management and infrastructure inspection costs. These changes to Ameren Missouri’s recovery mechanisms are expected to contribute to regulatory lag. The order did approve the continued use of the regulatory tracking mechanisms for pension and other postretirement benefits, renewable energy standard costs, solar rebates, and uncertain tax positions that the MoPSC authorized in prior electric rate orders. In addition, the order approved a reduction to Noranda’s electric rates with an offsetting increase in electric rates for Ameren Missouri’s other customers. The rate shift is revenue neutral to Ameren Missouri. In June 2015, Ameren Missouri filed an appeal with the Missouri Court of Appeals, Western District, of the reduction to Noranda’s electric rates included in the MoPSC’s order. The outcome of this appeal is not expected to impact Ameren Missouri’s results of operations, financial position, or liquidity. MEEIA Filing The MEEIA established a regulatory framework that, among other things, requires the MoPSC to ensure that a utility’s financial incentives are aligned to help customers use energy more efficiently, to provide timely cost recovery, and to provide earnings opportunities associated with cost-effective energy efficiency programs. Missouri does not have a law mandating energy efficiency programs. In August 2012, the MoPSC approved Ameren Missouri’s customer energy efficiency programs, net shared benefits, and performance incentive for 2013 through 2015. The 2013 through 2015 plan anticipated Ameren Missouri would invest up to $147 million in customer energy efficiency programs, realize $100 million of net shared benefits, and be eligible for a performance incentive that would allow it the potential to earn additional revenues by achieving certain customer energy efficiency goals, including $19 million if 100% of the goals are achieved during the three-year period, with the potential to earn a larger performance incentive if Ameren Missouri’s energy savings exceed those goals. From January 2013 through September 2015, Ameren Missouri invested $110 million in customer energy efficiency programs and realized $134 million of net shared benefits. In June 2015, the MoPSC staff filed a complaint case with the MoPSC regarding the method and inputs used in calculating the performance incentive. If the MoPSC agrees with the MoPSC staff’s interpretation of the August 2012 MEEIA order, the performance incentive recognized in 2016 would be significantly less than the performance incentive calculated using Ameren Missouri’s interpretation. Ameren Missouri has not recorded revenues associated with the performance incentive. However, regardless of the MoPSC’s decision in the complaint case, Ameren Missouri believes it will exceed 100% of the customer energy efficiency goals, subject to MoPSC review, and therefore expects to recognize revenues of at least $19 million in 2016. There is no date by which the MoPSC must issue a decision in this complaint case. In October 2015, the MoPSC rejected Ameren Missouri’s MEEIA energy efficiency plan for 2016 through 2018, which included a portfolio of customer energy efficiency programs along with a rider to collect the program costs, net shared benefits, and a performance incentive from customers. Ameren Missouri is studying the MoPSC’s October 2015 order and evaluating whether to file another proposed energy efficiency plan with the MoPSC. Noranda Contract Notification Ameren Missouri supplies electricity to Noranda’s aluminum smelter in southeast Missouri under a long-term power supply agreement. In May 2015, Ameren Missouri notified Noranda of its intent to terminate the agreement effective June 1, 2020. If Ameren Missouri wanted to cease providing electricity to Noranda, Ameren Missouri would also be required to obtain approval from the MoPSC. Sales to Noranda represented 5% of Ameren Missouri’s total electric revenue in 2014. ATXI Transmission Projects In May 2015, the MoPSC granted ATXI a certificate of convenience and necessity for the seven-mile portion of the Illinois Rivers project located in Missouri. In June 2015, ATXI made a filing with the MoPSC requesting a certificate of convenience and necessity for the Mark Twain project. The Mark Twain project is a MISO-approved 100-mile transmission line located in northeast Missouri. A decision is expected from the MoPSC in 2016. Illinois IEIMA Under the provisions of the IEIMA’s formula rate framework, which currently extends through 2019, Ameren Illinois’ electric delivery service rates are subject to an annual revenue requirement reconciliation to its actual recoverable costs. Throughout each year, Ameren Illinois records a regulatory asset or a regulatory liability and a corresponding increase or decrease to operating revenues for any differences between the revenue requirement reflected in customer rates for that year and its estimate of the probable increase or decrease in the revenue requirement expected to ultimately be approved by the ICC based on that year's actual recoverable costs incurred. As of September 30, 2015, Ameren Illinois had recorded regulatory assets of $52 million, $103 million, and $14 million, to reflect its expected 2015, 2014, and 2013 revenue requirement reconciliation adjustments, with interest, respectively. Ameren Illinois is collecting the 2013 revenue requirement reconciliation adjustment from customers during 2015. Ameren Illinois’ annual electric delivery service formula rate update to establish customer rates for 2016 is currently pending before the ICC. If the ICC approves as filed, the annual update filing would result in a $109 million increase in Ameren Illinois’ electric delivery service revenue requirement, beginning in January 2016. This update reflects an increase to the annual formula rate based on 2014 actual recoverable costs and expected net plant additions for 2015, an increase to include the 2014 revenue requirement reconciliation adjustment, and a decrease for the conclusion of the 2013 revenue requirement reconciliation adjustment, which will be fully collected from customers in 2015. In October 2015, the ICC staff submitted its calculation of Ameren Illinois’ revenue requirement. The ICC staff recommended adjustments that would result in a $107 million increase in Ameren Illinois’ electric delivery service revenue requirement. An ICC decision on this update filing is required by December 2015. 2015 Natural Gas Delivery Service Rate Case In January 2015, Ameren Illinois filed a request with the ICC seeking approval to increase its annual revenues for natural gas delivery service. In an attempt to reduce regulatory lag, Ameren Illinois used a 2016 future test year in this proceeding. Additionally, the request included a proposal to implement a volume balancing adjustment for residential and small nonresidential customers. The volume balancing adjustment would increase or decrease revenues as weather deviates from normal conditions to ensure that weather-related changes in natural gas sales volumes do not result in an over or under collection of natural gas revenues for these rate classes. This case includes a capital structure composed of 50% common equity and a rate base of $1.2 billion. In July 2015, Ameren Illinois, the ICC staff, and certain other intervenors filed a stipulation and agreement with the ICC that would result in rates that are based on a return on common equity of 9.6%. The agreement does not address the positions of all of the parties in the rate case. Based on the terms in the agreement and the unresolved positions in the case, Ameren Illinois' request seeks an annual revenue increase of $45 million, which is consistent with the ICC staff’s recommendation and the administrative law judges' proposed order issued in November 2015. The administrative law judges' order also proposed the approval of the volume balancing adjustment. A decision by the ICC in this proceeding is required by December 2015, with new rates expected to be effective in January 2016. Ameren Illinois cannot predict the level of any delivery service rate changes the ICC may approve, whether the ICC will approve the volume balancing adjustment, or if the ICC will approve the agreement between Ameren Illinois, the ICC staff, and certain other intervenors. In addition, Ameren Illinois cannot predict whether any rate changes that may eventually be approved will be sufficient to enable Ameren Illinois to recover its costs and to earn a reasonable return on investments when the rate changes go into effect. 2015 ICC Purchased Power Reconciliation In January 2015, the ICC issued an order that approved Ameren Illinois' reconciliation of revenues collected under its purchased power rider mechanism and Ameren Illinois' related cumulative power usage cost. In the first quarter of 2015, based on the January 2015 order, both Ameren and Ameren Illinois recorded a $15 million increase to electric revenues for the recovery of this cumulative power usage cost from electric customers. ATXI Transmission Project The Spoon River project is a MISO-approved 46-mile transmission line to be constructed in northwest Illinois. In September 2015, the ICC granted a certificate of public convenience and necessity and project approval for the Spoon River project. Federal Ameren Illinois Electric Transmission Rate Refund In July 2012, the FERC issued an order concluding that Ameren Illinois improperly included acquisition premiums, including goodwill, in determining the common equity used in its electric transmission formula rate and thereby inappropriately recovered a higher amount from its electric transmission customers. The order required Ameren Illinois to make refunds to customers for such improperly included amounts. In July 2015, the FERC approved a settlement agreement between Ameren Illinois and the affected customers. The settlement agreement required Ameren Illinois to make refunds and payments of $8 million to electric transmission customers, all of which was paid by September 30, 2015. The settlement agreement also requires Ameren Illinois to take other actions, such as reducing common equity for electric transmission ratemaking purposes on a prospective basis. FERC Complaint Cases In November 2013, a customer group filed a complaint case with the FERC seeking a reduction in the allowed base return on common equity for the FERC-regulated MISO transmission rate base under the MISO tariff to 9.15%. Currently, the FERC-allowed base return on common equity for MISO transmission owners is 12.38%. The FERC scheduled the case for hearing proceedings, requiring a proposed order from its administrative law judge to be issued no later than November 30, 2015, which will subsequently require FERC approval. The FERC has previously utilized a calculation to establish the allowed base return on common equity, which requires multiple inputs based on observable market data specific to the utility industry and broader macroeconomic data spanning unique time periods for each return on equity complaint case. We expect observable market data for the six months ended February 11, 2015, will be used in the November 2013 complaint case. As the maximum FERC-allowed refund period for the November 2013 complaint case ended in February 2015, another customer complaint case was filed in February 2015. The February 2015 complaint case seeks a reduction in the allowed base return on common equity for the FERC-regulated MISO transmission rate base under the MISO tariff to 8.67%. The FERC scheduled the February 2015 complaint case for hearing proceedings, requiring a proposed order from its administrative law judge to be issued no later than June 30, 2016, which will subsequently require FERC approval. We expect observable market data for the six months ended December 31, 2015, will be used in the February 2015 complaint case. As of September 30, 2015, Ameren and Ameren Illinois had current regulatory liabilities of $36 million and $25 million, respectively, representing their estimates of the potential refunds from the November 12, 2013 refund effective date. Ameren’s and Ameren Illinois’ recorded liabilities reflect their interpretation of the method and inputs used in the FERC’s calculation to establish the allowed base return on common equity, based on observable market data for the six months ended February 11, 2015, with respect to the November 2013 complaint case refund period, and based on observable market data through September 30, 2015, with respect to the February 2015 complaint case refund period. Ameren’s and Ameren Illinois’ liabilities also reflect the incentive adder discussed below, which became effective in early January 2015. Ameren Missouri did not record a liability as of September 30, 2015, and does not expect that a reduction in the FERC-allowed base return on common equity for MISO transmission owners would be material to its results of operations, financial position, or liquidity. A 50 basis point reduction in the FERC-allowed return on common equity would reduce Ameren's and Ameren Illinois' annual earnings by an estimated $4 million and $2 million, respectively, based on 2015 projected rate base. On January 6, 2015, a FERC-approved incentive adder of up to 50 basis points on the allowed base return on common equity for our participation in an RTO became effective. Upon the issuance of the final order addressing the initial MISO complaint case, beginning with its January 6, 2015 effective date, the incentive adder will reduce any refund to customers relating to a reduction of the base return on common equity. Combined Construction and Operating License In 2008, Ameren Missouri filed an application with the NRC for a COL for a second nuclear unit at Ameren Missouri's existing Callaway County, Missouri, energy center site. In 2009, Ameren Missouri suspended its efforts to build a second nuclear unit at its existing Callaway site, and the NRC suspended review of the COL application. Prior to suspending its efforts, Ameren Missouri had capitalized $69 million related to the project. Due primarily to changes in vendor support for licensing efforts at the NRC, Ameren Missouri’s assessment of long-term capacity needs, declining costs of alternative generation technologies, and the regulatory framework in Missouri, Ameren Missouri discontinued its efforts to license and build a second nuclear unit at its existing Callaway site. As a result of this decision, in the second quarter of 2015, Ameren and Ameren Missouri recognized a $69 million noncash pretax provision for all of the previously capitalized costs of the COL. Ameren Missouri has withdrawn its COL application with the NRC.

RATE AND REGULATORY MATTERS

Below is a summary of updates to significant regulatory proceedings and related lawsuits. See also Note 2 - Rate and Regulatory Matters under Part II, Item 8, of the Form 10-K. We are unable to predict the ultimate outcome of these matters, the timing of the final decisions of the various agencies and courts, or the impact on our results of operations, financial position, or liquidity.

Missouri

2015 Electric Rate Order

In April 2015, the MoPSC issued an order approving an increase in Ameren Missouri’s annual revenues for electric service of $122 million, including $109 million related to the increase in net energy costs above those included in base rates previously authorized by the MoPSC. The revenue increase was based on a 9.53% return on common equity, a capital structure composed of 51.8% common equity, and a rate base of $7.0 billion to reflect investments through December 31, 2014. Rate changes consistent with the order became effective on May 30, 2015.

The order approved Ameren Missouri’s request for continued use of the FAC; however, it changed the FAC to exclude all transmission revenues and substantially all transmission charges. In addition, the order did not approve the continued use of the regulatory tracking mechanisms for storm costs and vegetation management and infrastructure inspection costs. These changes to Ameren Missouri’s recovery mechanisms are expected to contribute to regulatory lag. The order did approve the continued use of the regulatory tracking mechanisms for pension and other postretirement benefits, renewable energy standard costs, solar rebates, and uncertain tax positions that the MoPSC authorized in prior electric rate orders.

In addition, the order approved a reduction to Noranda’s electric rates with an offsetting increase in electric rates for Ameren Missouri’s other customers. The rate shift is revenue neutral to Ameren Missouri.

In June 2015, Ameren Missouri filed an appeal with the Missouri Court of Appeals, Western District, of the reduction to Noranda’s electric rates included in the MoPSC’s order. The outcome of this appeal is not expected to impact Ameren Missouri’s results of operations, financial position, or liquidity.

MEEIA Filing

The MEEIA established a regulatory framework that, among other things, requires the MoPSC to ensure that a utility’s financial incentives are aligned to help customers use energy more efficiently, to provide timely cost recovery, and to provide earnings opportunities associated with cost-effective energy efficiency programs. Missouri does not have a law mandating energy efficiency programs.

In August 2012, the MoPSC approved Ameren Missouri’s customer energy efficiency programs, net shared benefits, and performance incentive for 2013 through 2015. The 2013 through 2015 plan anticipated Ameren Missouri would invest up to $147 million in customer energy efficiency programs, realize $100 million of net shared benefits, and be eligible for a performance incentive that would allow it the potential to earn additional revenues by achieving certain customer energy efficiency goals, including $19 million if 100% of the goals are achieved during the three-year period, with the potential to earn a larger performance incentive if Ameren Missouri’s energy savings exceed those goals. From January 2013 through September 2015, Ameren Missouri invested $110 million in customer energy efficiency programs and realized $134 million of net shared benefits. In June 2015, the MoPSC staff filed a complaint case with the MoPSC regarding the method and inputs used in calculating the performance incentive. If the MoPSC agrees with the MoPSC staff’s interpretation of the August 2012 MEEIA order, the performance incentive recognized in 2016 would be significantly less than the performance incentive calculated using Ameren Missouri’s interpretation. Ameren Missouri has not recorded revenues associated with the performance incentive. However, regardless of the MoPSC’s decision in the complaint case, Ameren Missouri believes it will exceed 100% of the customer energy efficiency goals, subject to MoPSC review, and therefore expects to recognize revenues of at least $19 million in 2016. There is no date by which the MoPSC must issue a decision in this complaint case.

In October 2015, the MoPSC rejected Ameren Missouri’s MEEIA energy efficiency plan for 2016 through 2018, which included a portfolio of customer energy efficiency programs along with a rider to collect the program costs, net shared benefits, and a performance incentive from customers. Ameren Missouri is studying the MoPSC’s October 2015 order and evaluating whether to file another proposed energy efficiency plan with the MoPSC.

Noranda Contract Notification

Ameren Missouri supplies electricity to Noranda’s aluminum smelter in southeast Missouri under a long-term power supply agreement. In May 2015, Ameren Missouri notified Noranda of its intent to terminate the agreement effective June 1, 2020. If Ameren Missouri wanted to cease providing electricity to Noranda, Ameren Missouri would also be required to obtain approval from the MoPSC. Sales to Noranda represented 5% of Ameren Missouri’s total electric revenue in 2014.

ATXI Transmission Projects

In May 2015, the MoPSC granted ATXI a certificate of convenience and necessity for the seven-mile portion of the Illinois Rivers project located in Missouri.

In June 2015, ATXI made a filing with the MoPSC requesting a certificate of convenience and necessity for the Mark Twain project. The Mark Twain project is a MISO-approved 100-mile transmission line located in northeast Missouri. A decision is expected from the MoPSC in 2016.

Illinois

IEIMA

Under the provisions of the IEIMA’s formula rate framework, which currently extends through 2019, Ameren Illinois’ electric delivery service rates are subject to an annual revenue requirement reconciliation to its actual recoverable costs. Throughout each year, Ameren Illinois records a regulatory asset or a regulatory liability and a corresponding increase or decrease to operating revenues for any differences between the revenue requirement reflected in customer rates for that year and its estimate of the probable increase or decrease in the revenue requirement expected to ultimately be approved by the ICC based on that year's actual recoverable costs incurred. As of September 30, 2015, Ameren Illinois had recorded regulatory assets of $52 million, $103 million, and $14 million, to reflect its expected 2015, 2014, and 2013 revenue requirement reconciliation adjustments, with interest, respectively. Ameren Illinois is collecting the 2013 revenue requirement reconciliation adjustment from customers during 2015.

Ameren Illinois’ annual electric delivery service formula rate update to establish customer rates for 2016 is currently pending before the ICC. If the ICC approves as filed, the annual update filing would result in a $109 million increase in Ameren Illinois’ electric delivery service revenue requirement, beginning in January 2016. This update reflects an increase to the annual formula rate based on 2014 actual recoverable costs and expected net plant additions for 2015, an increase to include the 2014 revenue requirement reconciliation adjustment, and a decrease for the conclusion of the 2013 revenue requirement reconciliation adjustment, which will be fully collected from customers in 2015. In October 2015, the ICC staff submitted its calculation of Ameren Illinois’ revenue requirement. The ICC staff recommended adjustments that would result in a $107 million increase in Ameren Illinois’ electric delivery service revenue requirement. An ICC decision on this update filing is required by December 2015.

2015 Natural Gas Delivery Service Rate Case

In January 2015, Ameren Illinois filed a request with the ICC seeking approval to increase its annual revenues for natural gas delivery service. In an attempt to reduce regulatory lag, Ameren Illinois used a 2016 future test year in this proceeding. Additionally, the request included a proposal to implement a volume balancing adjustment for residential and small nonresidential customers. The volume balancing adjustment would increase or decrease revenues as weather deviates from normal conditions to ensure that weather-related changes in natural gas sales volumes do not result in an over or under collection of natural gas revenues for these rate classes. This case includes a capital structure composed of 50% common equity and a rate base of $1.2 billion. In July 2015, Ameren Illinois, the ICC staff, and certain other intervenors filed a stipulation and agreement with the ICC that would result in rates that are based on a return on common equity of 9.6%. The agreement does not address the positions of all of the parties in the rate case. Based on the terms in the agreement and the unresolved positions in the case, Ameren Illinois' request seeks an annual revenue increase of $45 million, which is consistent with the ICC staff’s recommendation and the administrative law judges' proposed order issued in November 2015. The administrative law judges' order also proposed the approval of the volume balancing adjustment.

A decision by the ICC in this proceeding is required by December 2015, with new rates expected to be effective in January 2016. Ameren Illinois cannot predict the level of any delivery service rate changes the ICC may approve, whether the ICC will approve the volume balancing adjustment, or if the ICC will approve the agreement between Ameren Illinois, the ICC staff, and certain other intervenors. In addition, Ameren Illinois cannot predict whether any rate changes that may eventually be approved will be sufficient to enable Ameren Illinois to recover its costs and to earn a reasonable return on investments when the rate changes go into effect.

2015 ICC Purchased Power Reconciliation

In January 2015, the ICC issued an order that approved Ameren Illinois' reconciliation of revenues collected under its purchased power rider mechanism and Ameren Illinois' related cumulative power usage cost. In the first quarter of 2015, based on the January 2015 order, both Ameren and Ameren Illinois recorded a $15 million increase to electric revenues for the recovery of this cumulative power usage cost from electric customers.

ATXI Transmission Project

The Spoon River project is a MISO-approved 46-mile transmission line to be constructed in northwest Illinois. In September 2015, the ICC granted a certificate of public convenience and necessity and project approval for the Spoon River project.

Federal

Ameren Illinois Electric Transmission Rate Refund

In July 2012, the FERC issued an order concluding that Ameren Illinois improperly included acquisition premiums, including goodwill, in determining the common equity used in its electric transmission formula rate and thereby inappropriately recovered a higher amount from its electric transmission customers. The order required Ameren Illinois to make refunds to customers for such improperly included amounts.

In July 2015, the FERC approved a settlement agreement between Ameren Illinois and the affected customers. The settlement agreement required Ameren Illinois to make refunds and payments of $8 million to electric transmission customers, all of which was paid by September 30, 2015. The settlement agreement also requires Ameren Illinois to take other actions, such as reducing common equity for electric transmission ratemaking purposes on a prospective basis.

FERC Complaint Cases

In November 2013, a customer group filed a complaint case with the FERC seeking a reduction in the allowed base return on common equity for the FERC-regulated MISO transmission rate base under the MISO tariff to 9.15%. Currently, the FERC-allowed base return on common equity for MISO transmission owners is 12.38%. The FERC scheduled the case for hearing proceedings, requiring a proposed order from its administrative law judge to be issued no later than November 30, 2015, which will subsequently require FERC approval. The FERC has previously utilized a calculation to establish the allowed base return on common equity, which requires multiple inputs based on observable market data specific to the utility industry and broader macroeconomic data spanning unique time periods for each return on equity complaint case. We expect observable market data for the six months ended February 11, 2015, will be used in the November 2013 complaint case. As the maximum FERC-allowed refund period for the November 2013 complaint case ended in February 2015, another customer complaint case was filed in February 2015. The February 2015 complaint case seeks a reduction in the allowed base return on common equity for the FERC-regulated MISO transmission rate base under the MISO tariff to 8.67%. The FERC scheduled the February 2015 complaint case for hearing proceedings, requiring a proposed order from its administrative law judge to be issued no later than June 30, 2016, which will subsequently require FERC approval. We expect observable market data for the six months ended December 31, 2015, will be used in the February 2015 complaint case.

As of September 30, 2015, Ameren and Ameren Illinois had current regulatory liabilities of $36 million and $25 million, respectively, representing their estimates of the potential refunds from the November 12, 2013 refund effective date. Ameren’s and Ameren Illinois’ recorded liabilities reflect their interpretation of the method and inputs used in the FERC’s calculation to establish the allowed base return on common equity, based on observable market data for the six months ended February 11, 2015, with respect to the November 2013 complaint case refund period, and based on observable market data through September 30, 2015, with respect to the February 2015 complaint case refund period. Ameren’s and Ameren Illinois’ liabilities also reflect the incentive adder discussed below, which became effective in early January 2015. Ameren Missouri did not record a liability as of September 30, 2015, and does not expect that a reduction in the FERC-allowed base return on common equity for MISO transmission owners would be material to its results of operations, financial position, or liquidity. A 50 basis point reduction in the FERC-allowed return on common equity would reduce Ameren's and Ameren Illinois' annual earnings by an estimated $4 million and $2 million, respectively, based on 2015 projected rate base.

On January 6, 2015, a FERC-approved incentive adder of up to 50 basis points on the allowed base return on common equity for our participation in an RTO became effective. Upon the issuance of the final order addressing the initial MISO complaint case, beginning with its January 6, 2015 effective date, the incentive adder will reduce any refund to customers relating to a reduction of the base return on common equity.

Combined Construction and Operating License

In 2008, Ameren Missouri filed an application with the NRC for a COL for a second nuclear unit at Ameren Missouri's existing Callaway County, Missouri, energy center site. In 2009, Ameren Missouri suspended its efforts to build a second nuclear unit at its existing Callaway site, and the NRC suspended review of the COL application. Prior to suspending its efforts, Ameren Missouri had capitalized $69 million related to the project. Due primarily to changes in vendor support for licensing efforts at the NRC, Ameren Missouri’s assessment of long-term capacity needs, declining costs of alternative generation technologies, and the regulatory framework in Missouri, Ameren Missouri discontinued its efforts to license and build a second nuclear unit at its existing Callaway site. As a result of this decision, in the second quarter of 2015, Ameren and Ameren Missouri recognized a $69 million noncash pretax provision for all of the previously capitalized costs of the COL. Ameren Missouri has withdrawn its COL application with the NRC.