COMMITMENTS AND CONTINGENCIES	3 Months Ended
COMMITMENTS AND CONTINGENCIES	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Environmental Matters Set forth below are descriptions of contingencies related to environmental matters that may impact the Evergy Companies' operations or their financial results. Management's assessment of these contingencies, which are based on federal and state statutes and regulations, and regulatory agency and judicial interpretations and actions, has evolved over time. These laws, regulations, interpretations and actions can also change, restrict or otherwise impact the Evergy Companies' operations or financial results. The failure to comply with these laws, regulations, interpretations and actions could result in the assessment of administrative, civil and criminal penalties and the imposition of remedial requirements. The Evergy Companies believe that all of their operations are in substantial compliance with current federal, state and local environmental standards. There are a variety of final and proposed laws and regulations that could have a material adverse effect on the Evergy Companies' operations and consolidated financial results. Due in part to the complex nature of environmental laws and regulations, the Evergy Companies are unable to assess the impact of potential changes that may develop with respect to the environmental contingencies described below. Clean Air Act - Startup, Shutdown and Malfunction (SSM) Regulation In 2015, the Environmental Protection Agency (EPA) issued a final rule addressing how state implementation plans (SIPs) can treat excess emissions during SSM events. This rule was referred to as the 2015 SIP Call Rule. The rule required 36 states to submit SIP revisions by November 2016 to remove certain exemptions and other discretionary enforcement provisions that apply to excess emissions during SSM events. Legal challenges ensued and the case was eventually placed in abeyance. In December 2021, the U.S. Court of Appeals for the D.C. Circuit (D.C. Circuit) restarted the litigation and oral arguments were held in March 2022. An additional case was also taking place in the U.S. District Court for the Northern District of California (District Court of Northern California) and in June 2022, the District Court of Northern California entered a final consent decree establishing deadlines for the EPA to take final action on SIP revisions that were submitted in response to the 2015 SIP Call Rule. Deadlines for 26 states and air districts, including Kansas, Missouri and Oklahoma, are listed in the final consent decree. Final action from the EPA could result in required SIP revisions in Oklahoma, Kansas and Missouri which could have a material impact on the Evergy Companies. If the D.C. Circuit overturns the EPA's 2015 SIP Call Rule, the final consent decree's deadlines will no longer be valid. Mercury and Air Toxics Standards (MATS) In April 2023, the EPA released a proposal to tighten certain aspects of the MATS rule. The EPA is proposing to lower the emission limit for particulate matter (PM), require the use of PM continuous emissions monitors (CEMS) and lower the mercury emission limit for lignite coal-fired electric generating units (EGUs). The EPA is also soliciting comment on further strengthening of the PM emission limitation. Due to uncertainty regarding final actions on the MATS rule, the Evergy Companies are unable to accurately assess the impacts of these potential EPA actions on their operations or consolidated financial results, but the cost to comply with the emission limitations as proposed do not appear to be material. Ozone Interstate Transport State Implementation Plans (ITSIP) In 2015, the EPA lowered the Ozone National Ambient Air Quality Standards (NAAQS) from 75 ppb to 70 ppb. Impacted states were required to submit ITSIPs in 2018 to comply with the "Good Neighbor Provision" of the Clean Air Act (CAA). The EPA did not act on these ITSIP submissions by the deadline established in the CAA and entered consent decrees establishing deadlines to take final action on various ITSIPs. In February 2022, the EPA published a proposed rule to disapprove of ITSIPs submitted by nineteen states including Missouri and Oklahoma. In April 2022, the EPA published a final approval of the Kansas ITSIP in the Federal Register. MDNR submitted a supplemental ITSIP to the EPA on November 1, 2022. In February 2023, the EPA published a final rule disapproving the ITSIPs submitted by 19 states, including the final disapproval of the Missouri and Oklahoma ITSIPs. In April 2023, the Attorneys General of Missouri and Oklahoma have filed Petitions for Review in the U.S. 8th and 10th Circuit Courts of Appeals, respectively, challenging the EPA disapproval. Ozone Interstate Transport Federal Implementation Plans (ITFIP) In April 2022, the EPA published in the Federal Register the proposed ITFIP to resolve outstanding "Good Neighbor" obligations with respect to the 2015 Ozone NAAQS for 26 states including Missouri and Oklahoma. This ITFIP would establish a revised Cross-State Air Pollution Rule (CSAPR) ozone season nitrogen oxide (NOx) emissions trading program for electric generating units (EGUs) beginning in 2023 and would limit ozone season NOx emissions from certain industrial stationary sources beginning in 2026. The proposed rule would also establish a new daily backstop NOx emissions rate limit for applicable coal-fired units larger than 100 MW, as well as unit-specific NOx emission rate limits for certain industrial emission units and would feature "dynamic" adjustments of emission budgets for EGUs beginning with ozone season 2025. The proposed ITFIP includes reductions to the state ozone season NOx budgets for Missouri and Oklahoma beginning in 2023 with additional reductions in future years. The Evergy Companies provided formal comments as part of the rulemaking process. In March 2023, the EPA issued the final ITFIPs for twenty-three states, including Missouri and Oklahoma. While the Evergy Companies are continuing to evaluate the impacts of the ITFIP, there are uncertainties beginning in 2030 regarding the implementation of dynamic budgeting and reduced banking that could have an impact on their operations and the cost to comply could be material. Particulate Matter and Ozone National Ambient Air Quality Standards In January 2023, the EPA proposed strengthening the primary annual PM2.5 (particulate matter less than 2.5 microns in diameter) NAAQS. The EPA is proposing to lower the primary annual PM2.5 NAAQS from 12.0 µg/m3 (micrograms per cubic meter) to a level that would be between 9.0 and 10.0 µg/m3. The EPA is proposing to retain the other PM NAAQS at their current levels. The EPA is also in the process of reconsidering its December 2020 decision to retain each of the Ozone NAAQS at the level set in 2015. Due to uncertainty regarding the potential lowering of the ozone and PM2.5 NAAQS, the Evergy Companies are unable to accurately assess the impacts of these potential EPA actions on their operations or consolidated financial results, but the cost to comply with lower future ozone or PM2.5 NAAQS could be material. Regional Haze Rule In 1999, the EPA finalized the Regional Haze Rule which aims to restore national parks and wilderness areas to pristine conditions. The rule requires states in coordination with the EPA, the National Park Service, the U.S. Fish and Wildlife Service, the U.S. Forest Service, and other interested parties to develop and implement air quality protection plans to reduce the pollution that causes visibility impairment. There are 156 "Class I" areas across the U.S. that must be restored to pristine conditions by the year 2064. There are no Class I areas in Kansas, whereas Missouri has two: the Hercules-Glades Wilderness Area and the Mingo Wilderness Area. States must submit revisions to their Regional Haze Rule SIPs every ten years and the first round was due in 2007. For the second ten-year implementation period, the EPA issued a final rule revision in 2017 that allowed states to submit their SIP revisions by July 31, 2021. The Missouri SIP revision does not require any additional reductions from the Evergy Companies' generating units in the state. MDNR submitted the Missouri SIP revision to the EPA in August 2022, however, they failed to do so by the EPA's revised submittal deadline of August 15, 2022. As a result, on August 30, 2022, the EPA published "finding of failure" with respect to Missouri and fourteen other states for failing to submit their Regional Haze SIP revisions by the applicable deadline. This finding of failure established a two-year deadline for the EPA to issue a Regional Haze federal implementation plan (FIP) for each state unless the state submits and the EPA approves a revised SIP that meets all applicable requirements before the EPA issues the FIP. The Kansas SIP revision was placed on public notice in June 2021 and requested no additional emission reductions by electric utilities based on the significant reductions that were achieved during the first implementation period. The EPA provided comments on the Kansas SIP revision in June 2021 that each state is statutorily required to conduct a "four-factor analysis" on at least two sources within the state to help determine if further emission reductions are necessary. The EPA also stated it would be difficult to approve the Kansas SIP revision if at least two four-factor analyses are not conducted on Kansas emission sources. Kansas Department Health and Environment (KDHE) submitted the Kansas SIP revision in July 2021. If a Kansas generating unit of the Evergy Companies is selected for analysis, the possibility exists that the state or the EPA, through a revised SIP or a FIP, could determine that additional operational or physical modifications are required on the generating unit to further reduce emissions. The overall cost of those modifications could be material to the Evergy Companies. In March 2023, several environmental organizations notified the EPA of their intent to sue for failure of the EPA to timely approve or disapprove of the SIP revisions submitted by Kansas and seven other states. Greenhouse Gases Burning coal and other fossil fuels releases carbon dioxide (CO2) and other gases referred to as greenhouse gases (GHG). Various regulations under the CAA limit CO2 and other GHG emissions, and in addition, other measures are being imposed or offered by individual states, municipalities and regional agreements with the goal of reducing GHG emissions. In January 2023, the EPA announced its intent to propose GHG regulations that would apply to new and existing EGUs by the end of the second quarter 2023. Due to uncertainty regarding the future of the EPA's GHG regulations, the Evergy Companies cannot determine the impacts on their operations or consolidated financial results, but the cost to comply with potential GHG rules could be material. Water The Evergy Companies discharge some of the water used in generation and other operations containing substances deemed to be pollutants. A November 2015 EPA rule applicable to steam-electric power generating plants establishes effluent limitations guidelines (ELG) and standards for wastewater discharges, including limits on the amount of toxic metals and other pollutants that can be discharged. Implementation timelines for this 2015 rule vary from 2018 to 2023. In April 2019, the U.S. Court of Appeals for the 5th Circuit (5th Circuit) issued a ruling that vacated and remanded portions of the original ELG rule. Due to this ruling, the EPA announced a plan in July 2021 to issue a proposed rule in the fall of 2022 to address the vacated limitations for legacy wastewater and landfill leachate. This proposed rule was issued in pre-publication format published in the Federal Register in March 2023. This proposed rulemaking establishes the requirement for zero liquid discharge of flue gas desulfurization (FGD) wastewater and bottom ash transport water as well as additional restrictions on coal combustion residual landfill leachate. Legacy wastewater is addressed in the proposal but referred to state regulators to enforce limitations according to the permit writers' best professional judgement. The Evergy Companies have reviewed the proposed modifications to limitations on FGD wastewater and bottom ash transport water and if the regulation is finalized as proposed, the Evergy Companies do not believe the impact to be material. Modifications for best available technology economically available for the discharge of landfill leachate could be material if the rulemaking is finalized as proposed. In August 2021, based on an order issued by the U.S. District Court for the District of Arizona, which vacated and remanded the EPA's 2020 Navigable Waters Protection Rule (NWPR), the EPA and the U.S. Army Corps of Engineers announced that they had halted implementation of the NWPR nationwide, and were interpreting "Waters of the United States" consistent with the regulatory regime that was in place prior to 2015. In December 2021, the EPA and the Department of the Army published a proposed rule that would formally repeal the NWPR and revise the definition of "Waters of the United States." In December 2022, the EPA and the Department of the Army issued a final rule establishing a definition for "Waters of the United States." The final rule was published in the federal register in January 2023 and took effect in March 2023. A case is also pending in the Supreme Court regarding the proper scope of "Waters of the United States" that could affect the final rule. The Evergy Companies are reviewing the final rulemaking and awaiting the Supreme Court's decision. The impact on the Evergy Companies' operations or consolidated financial results are not expected to be material. Regulation of Coal Combustion Residuals In the course of operating their coal generation plants, the Evergy Companies produce coal combustion residuals (CCRs), including fly ash, gypsum and bottom ash. The EPA published a rule to regulate CCRs in April 2015 that requires additional CCR handling, processing and storage equipment and closure of certain ash disposal units. In January 2022, the EPA published proposed determinations for facilities that filed closure extensions for unlined or clay-lined CCR units. These proposed determinations include various interpretations of the CCR regulations and compliance expectations that may impact all owners of CCR units. These interpretations could require modified compliance plans such as different methods of CCR unit closure. Additionally, more stringent remediation requirements for units that are in corrective action or forced to go into corrective action are possible. In April 2022, the Utility Solid Waste Activities Group (USWAG) and other interested parties filed similar petitions in the D.C. Circuit challenging the EPA's legal positions regarding the CCR rule determinations proposed in January 2022. Some CCR units at Lawrence Energy Center and Sibley Station have moved into corrective action. In January 2022, the EPA issued a "Notice of Potential Violation" to the Tecumseh Energy Center (TEC) suggesting a closed CCR impoundment should enter corrective action. In November 2022, Evergy agreed to a Consent Agreement and Final Order (CAFO) with the EPA Region 7 addressing the alleged potential violation. In the CAFO, Evergy agreed to re-open the TEC CCR impoundment for further assessment of groundwater. As a result of the further assessments, the TEC impoundment entered groundwater corrective actions in March 2023. It is possible that the other CCR units at other generation stations could move into corrective action based on the EPA CCR rule interpretations, enforcement actions, or execution of the Evergy Companies' CCR strategy. The cost to comply with these proposed determinations by the EPA could be material. The Evergy Companies have recorded AROs for their current estimates for the closure of ash disposal ponds and landfills, but the revision of these AROs may be required in the future due to changes in existing CCR regulations, the results of groundwater monitoring of CCR units or changes in interpretation of existing CCR regulations or changes in the timing or cost to close ash disposal ponds and landfills. The revision of AROs for regulated operations has no income statement impact due to the deferral of the adjustments through a regulatory asset. If revisions to these AROs are necessary, the impact on the Evergy Companies' operations or consolidated financial results could be material.