Commitments and Contingencies	6 Months Ended
Jun. 30, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Environmental DTE Electric Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. Additional rulemakings may occur over the next few years which could require additional controls for SO2, NOX, and other hazardous air pollutants. The EPA proposed revised air quality standards for ground level ozone in November 2014 and specifically requested comments on the form and level of the ozone standards. The standards were finalized in October 2015. The State of Michigan recommended to the EPA in October 2016 which areas of the state are not attaining the new standard. On April 30, 2018, the EPA finalized the State of Michigan's recommended marginal non-attainment designation for southeast Michigan. The State is required to develop and implement a plan to address the southeast Michigan ozone non-attainment area by the end of 2021. The Registrants cannot predict the scope and associated financial impact of the State's plan to address the ozone non-attainment area at this time. The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel fired EGUs. The performance standards for existing EGUs, known as the EPA Clean Power Plan, were challenged by petitioners and stayed by the U.S. Supreme Court in February 2016 pending final review by the courts. On October 10, 2017, the EPA, under a new administration, proposed to rescind the Clean Power Plan, and in August 2018, the EPA proposed revised emission guidelines for GHGs from existing EGUs. On June 19, 2019, the EPA Administrator officially repealed the Clean Power Plan and finalized its replacement, named the ACE rule. The ACE rule was vacated and remanded back to the EPA in a D.C. Circuit Court decision on January 19, 2021. The next steps taken by the EPA with respect to regulation of GHGs from EGUs is uncertain. Regardless of future rules, DTE Energy remains committed for its electric utility operations to reduce carbon emissions 32% by 2023, 50% by 2030, and 80% by 2040 from 2005 carbon emissions levels, and its goal of net zero emissions for its electric utility operations by 2050. In addition to the GHG standards for existing EGUs, in December 2018, the EPA issued proposed revisions to the carbon dioxide performance standards for new, modified, or reconstructed fossil-fuel fired EGUs. The carbon standards for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards. Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC. To comply with air pollution requirements, DTE Electric has spent approximately $2.4 billion. DTE Electric does not anticipate additional capital expenditures for air pollution requirements through 2025, subject to the results of future rulemakings. Water — In response to an EPA regulation, DTE Electric was required to examine alternatives for reducing the environmental impacts of the cooling water intake structures at several of its facilities. Based on the results of completed studies and expected future studies, DTE Electric may be required to install technologies to reduce the impacts of the water intake structures. A final rule became effective in October 2014. The final rule requires studies to be completed and submitted as part of the NPDES permit application process to determine the type of technology needed to reduce impacts to fish. DTE Electric has initiated the process of completing the required studies. Final compliance for the installation of any required technology will be determined by the state on a case by case, site specific basis. DTE Electric is currently evaluating the compliance options and working with the State of Michigan on evaluating whether any controls are needed. These evaluations/studies may require modifications to some existing intake structures. It is not possible to quantify the impact of this rulemaking at this time. Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Electric conducted remedial investigations at contaminated sites, including three former MGP sites. Cleanup of one of the MGP sites is complete, and the site is closed. The investigations have revealed contamination related to the by-products of gas manufacturing at each MGP site. In addition to the MGP sites, DTE Electric is also in the process of cleaning up other contaminated sites, including the area surrounding an ash landfill, electrical distribution substations, electric generating power plants, and underground and above ground storage tank locations. The findings of these investigations indicated that the estimated cost to remediate these sites is expected to be incurred over the next several years. At June 30, 2021 and December 31, 2020, DTE Electric had $10 million accrued for remediation. These costs are not discounted to their present value. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Electric’s financial position and cash flows. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site. Coal Combustion Residuals and Effluent Limitations Guidelines — A final EPA rule for the disposal of coal combustion residuals, commonly known as coal ash, became effective in October 2015, and was revised in October 2016, July 2018, September 2020, and November 2020. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants subject to certain provisions in the CCR rule. At certain facilities, the rule currently requires ongoing sampling and testing of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant. On September 28, 2020, the CCR rule "A Holistic Approach to Closure Part A: Deadline to Initiate Closure and Enhancing Public Access to Information" became effective and establishes April 11, 2021 as the new deadline for all unlined impoundments (including units previously classified as "clay-lined") to initiate closure. Additionally, the rule amends certain reporting requirements and CCR website requirements. On November 12, 2020, an additional revision to the CCR Rule "A Holistic Approach to Closure Part B: Alternate Demonstration for Unlined Surface Impoundments" was published in the Federal Register that provides a process to determine if certain unlined impoundments consist of an alternative liner system that may be as protective as the current liners specified in the CCR rule, and therefore may continue to operate. DTE Electric has submitted applications to the EPA that support continued use of all impoundments through their active lives. The forced closure date of April 11, 2021 is effectively delayed while the EPA's review looks to extend beyond this date. At the State level, legislation was signed by the Governor in December 2018 and provides for further regulation of the CCR program in Michigan. Additionally, the bill provides the basis of a CCR program that EGLE has submitted to the EPA for approval to fully regulate the CCR program in Michigan in lieu of a Federal permit program. In October 2020, the EPA published in the Federal Register the final version of the ELG Reconsideration Rule which updates the 2015 ELG Rule (2015 Rule). The Reconsideration Rule re-establishes the technology-based effluent limitations guidelines and standards applicable to flue gas desulfurization (FGD) wastewater and bottom ash transport water. The EPA set the applicability dates for bottom ash transport water and FGD wastewater retrofits to be "as soon as possible" beginning October 13, 2021 and no later than December 31, 2025. Compliance schedules for individual facilities and individual waste streams are determined through issuance of new NPDES permits by the State of Michigan. The State of Michigan has issued a NPDES permit for the Belle River Power Plant establishing a compliance deadline of December 31, 2021 based on the 2015 Rule. Due to completion of the Reconsideration Rule in 2020, the compliance deadlines within the NPDES permit for Belle River Power Plant will be revised accordingly. No new permits that would require ELG compliance have been issued for other facilities, consequently no compliance timelines have been established. On April 12, 2017, the EPA granted a petition for reconsideration of the 2015 ELG Rule. The EPA also signed an administrative stay of the 2015 ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and FGD wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule (Postponement Rule) to postpone certain applicable deadlines within the 2015 ELG rule. The Postponement Rule was published on September 18, 2017. The Postponement Rule nullified the administrative stay but also extended the earliest compliance deadlines for only FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. On October 13, 2020, the EPA finalized the ELG Reconsideration Rule which revised the regulations from the 2015 ELG rule. The Reconsideration Rule revises requirements for two specific waste streams produced by steam electric power plants: FGD wastewater and bottom ash transport water. The Reconsideration Rule also provides additional compliance opportunities by finalizing low utilization and cessation of coal burning subcategories. The Reconsideration Rule provides new opportunities for DTE Electric to evaluate existing ELG compliance strategies and make any necessary adjustments to ensure full compliance with the ELGs in a cost-effective manner. DTE Electric is currently evaluating compliance strategies, technologies and system designs for both FGD wastewater and bottom ash transport water system to achieve compliance with the final rule. DTE Electric has estimated the impact of the CCR and ELG rules to be $718 million of capital expenditures, including $573 million for 2021 through 2025. DTE Gas Air — In June 2020, DTE Energy expanded its net zero goal to include its gas utility operations by committing to reduce greenhouse gas emissions to net zero by 2050 from procurement of natural gas through delivery. As part of DTE Energy's 2050 net zero commitment, DTE Gas launched its CleanVision Natural Gas Balance program in January 2021 that offers customers a way to reduce their carbon footprint using carbon offsets and renewable natural gas. The carbon offset program is focused on protecting Michigan forests that naturally absorb carbon dioxide. Contaminated and Other Sites — DTE Gas owns or previously owned 14 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. Cleanup of eight of the MGP sites is complete, and the sites are closed. DTE Gas has also completed partial closure of four additional sites. Cleanup activities associated with the remaining sites will continue over the next several years. The MPSC has established a cost deferral and rate recovery mechanism for investigation and remediation costs incurred at former MGP sites. In addition to the MGP sites, DTE Gas is also in the process of cleaning up other contaminated sites, including gate stations, gas pipeline releases, and underground storage tank locations. As of June 30, 2021 and December 31, 2020, DTE Gas had $23 million and $24 million, respectively, accrued for remediation. These costs are not discounted to their present value. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Gas' financial position and cash flows. DTE Gas anticipates the cost amortization methodology approved by the MPSC, which allows for amortization of the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent the associated investigation and remediation costs from having a material adverse impact on DTE Gas' results of operations. Non-utility DTE Energy's non-utility businesses are subject to a number of environmental laws and regulations dealing with the protection of the environment from various pollutants. In March 2019, the EPA issued an FOV to EES Coke, the Michigan coke battery facility that is a wholly-owned subsidiary of DTE Energy, alleging that the 2008 and 2014 permits issued by EGLE did not comply with the Clean Air Act. In September 2020, the EPA issued another FOV alleging EES Coke's 2018 and 2019 SO2 emissions exceeded projections and hence violated non-attainment new source review requirements. EES Coke evaluated the EPA's alleged violations and believes that the permits approved by EGLE complied with the Clean Air Act. EES Coke also responded to the EPA's September 2020 allegations demonstrating its actual emissions are compliant with non-attainment new source review requirements. Discussions with the EPA are ongoing. At the present time, DTE Energy cannot predict the outcome or financial impact of this FOV. Other In 2010, the EPA finalized a new one-hour SO2 ambient air quality standard that requires states to submit plans and associated timelines for non-attainment areas that demonstrate attainment with the new SO2 standard in phases. Phase 1 addresses non-attainment areas designated based on ambient monitoring data. Phase 2 addresses non-attainment areas with large sources of SO2 and modeled concentrations exceeding the National Ambient Air Quality Standards for SO2. Phase 3 addresses smaller sources of SO2 with modeled or monitored exceedances of the new SO2 standard. Michigan's Phase 1 non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Modeling runs by EGLE suggest that emission reductions may be required by significant sources of SO2 emissions in these areas, including DTE Electric power plants and DTE Energy's Michigan coke battery facility. As part Michigan's SIP process, DTE Energy has worked with EGLE to develop air permits reflecting significant SO2 emission reductions that, in combination with other non-DTE Energy sources' emission reduction strategies, will help the state attain the standard and sustain its attainment. The Michigan SIP was completed and submitted to the EPA on May 31, 2016 and supplemented on June 30, 2016. On March 19, 2021, the EPA published in the Federal Register partial approval and partial disapproval of Michigan's Detroit SO2 non-attainment area plan. The partial disapproval does not appear to impact DTE's sources and further discussions are underway with the EPA to finalize the plan. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of any further emissions reductions that may be required from DTE's facilities at this time. Michigan's Phase 2 non-attainment area includes DTE Electric facilities in St. Clair County. EGLE has not made a final determination on SIP strategy for this area, pending the EPA's review of a clean data determination request. Until agency plans are final, DTE Energy is unable to determine the impacts. Synthetic Fuel Guarantees DTE Energy discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. DTE Energy provided certain guarantees and indemnities in conjunction with the sales of interests in its synfuel facilities. The guarantees cover potential commercial, environmental, oil price, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at June 30, 2021 was approximately $400 million. Payment under these guarantees is considered remote. REF Guarantees DTE Energy has provided certain guarantees and indemnities in conjunction with the sales of interests in or lease of its REF facilities. The guarantees cover potential commercial, environmental, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at June 30, 2021 was $617 million. Payments under these guarantees are considered remote. Other Guarantees In certain limited circumstances, the Registrants enter into contractual guarantees. The Registrants may guarantee another entity’s obligation in the event it fails to perform and may provide guarantees in certain indemnification agreements. Finally, the Registrants may provide indirect guarantees for the indebtedness of others. DTE Energy’s guarantees are not individually material with maximum potential payments totaling $50 million at June 30, 2021. Payments under these guarantees are considered remote. The Registrants are periodically required to obtain performance surety bonds in support of obligations to various governmental entities and other companies in connection with its operations. As of June 30, 2021, DTE Energy had $176 million of performance bonds outstanding, including $120 million for DTE Electric. In the event that such bonds are called for nonperformance, the Registrants would be obligated to reimburse the issuer of the performance bond. The Registrants are released from the performance bonds as the contractual performance is completed and does not believe that a material amount of any currently outstanding performance bonds will be called. Vector Line of Credit In July 2019, DTE Energy, as lender, entered into a revolving term credit facility with Vector, as borrower, in the amount of C$70 million. The credit facility was executed in response to the passage of Canadian regulations requiring oil and gas pipelines to demonstrate their financial ability to respond to a catastrophic event and exists for the sole purpose of satisfying these regulations. Vector may only draw upon the facility if the funds are required to respond to a catastrophic event. The maximum potential payment under the line of credit at June 30, 2021 was $56 million. On July 7, 2021 and in conjunction with the separation of DT Midstream, DTE Energy transferred the credit facility to DT Midstream and DT Midstream assumed the lender role under the credit facility. Labor Contracts There are several bargaining units for DTE Energy subsidiaries' approximate 5,200 represented employees, including DTE Electric's approximately 2,700 represented employees. This represents 49% and 57% of DTE Energy's and DTE Electric's total employees, respectively. The majority of the represented employees are under contracts that expire in 2027. Purchase Commitments Utility capital expenditures, expenditures for non-utility businesses, and contributions to equity method investees will be approximately $3.9 billion and $3.0 billion in 2021 for DTE Energy and DTE Electric, respectively. The Registrants have made certain commitments in connection with the estimated 2021 annual capital expenditures and contributions to equity method investees. Bankruptcies DTE Energy Trading was the sole supplier of power for Brilliant Energy, LLC ("Brilliant"), a load serving entity and competitive retailer in ERCOT. During March 2021, Brilliant filed a voluntary petition for bankruptcy protection under Chapter 7 of the Bankruptcy Code. Subsequently, the bankruptcy court authorized a Trustee to continue managing Brilliant’s business to preserve any remaining value for their creditors and begin an orderly wind-down of Brilliant’s operations. In June 2021, DTE Energy Trading completed the transfer of service for all of Brilliant's customer contracts to utilities in the ERCOT market and has no further service responsibilities related to Brilliant. For pre-petition receivables that were reserved during the first quarter 2021, approximately $9 million remains reserved as of June 30, 2021. Other pre-petition receivables of approximately $3 million were recovered during the second quarter 2021 and uncollectible expense was reversed. The remaining wind-down activities are expected to be completed in the third quarter 2021. DTE Energy does not believe there is any additional risk related to this bankruptcy. COVID-19 Pandemic DTE Energy has been actively monitoring the impact of the COVID-19 pandemic on supply chains, markets, counterparties, and customers, and any related impacts on operating costs, customer demand, and recoverability of assets that could materially impact the Registrants' financial results. In 2021, the COVID-19 pandemic has continued to impact DTE Electric sales volumes. As businesses have maintained certain remote operations, related sales volumes have been lower for commercial and industrial customers and higher for residential customers as compared to historical volumes before the pandemic. This impact contributed to a net reduction in DTE Electric sales, but has been offset by favorable rate mix. In 2020, COVID-19 also resulted in incremental costs at our utilities related to personal protective equipment and other health and safety-related matters, as well as lower volumes for certain companies within the Power and Industrial Projects segment. For the three and six months ended June 30, 2021, however, there has not been any significant impact to the Registrants' Consolidated Financial Statements. In consideration of the above factors and all other current and expected impacts to the Registrants' performance and cash flows resulting from the COVID-19 pandemic, there have been no material adjustments or reserves deemed necessary as of June 30, 2021. The Registrants cannot predict the future impacts of the COVID-19 pandemic on the Consolidated Financial Statements, as developments involving COVID-19 and its related effects on economic and operating conditions remain highly uncertain. Other Contingencies The Registrants are involved in certain other legal, regulatory, administrative, and environmental proceedings before various courts, arbitration panels, and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits, inquiries from various regulators, and pending judicial matters. The Registrants cannot predict the final disposition of such proceedings. The Registrants regularly review legal matters and record provisions for claims that they can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Registrants' Consolidated Financial Statements in the periods they are resolved. For a discussion of contingencies related to regulatory matters and derivatives, see Notes 6 and 9 to the Consolidated Financial Statements, "Regulatory Matters" and "Financial and Other Derivative Instruments," respectively.

Air — DTE Electric is subject to the EPA ozone and fine particulate transport and acid rain regulations that limit power plant emissions of SO2 and NOX. The EPA and the State of Michigan have also issued emission reduction regulations relating to ozone, fine particulate, regional haze, mercury, and other air pollution. These rules have led to controls on fossil-fueled power plants to reduce SO2, NOX, mercury, and other emissions. Additional rulemakings may occur over the next few years which could require additional controls for SO2, NOX, and other hazardous air pollutants.

The EPA proposed revised air quality standards for ground level ozone in November 2014 and specifically requested comments on the form and level of the ozone standards. The standards were finalized in October 2015. The State of Michigan recommended to the EPA in October 2016 which areas of the state are not attaining the new standard. On April 30, 2018, the EPA finalized the State of Michigan's recommended marginal non-attainment designation for southeast Michigan. The State is required to develop and implement a plan to address the southeast Michigan ozone non-attainment area by the end of 2021. The Registrants cannot predict the scope and associated financial impact of the State's plan to address the ozone non-attainment area at this time.

The EPA has implemented regulatory actions under the Clean Air Act to address emissions of GHGs from the utility sector and other sectors of the economy. Among these actions, in 2015 the EPA finalized performance standards for emissions of carbon dioxide from new and existing fossil-fuel fired EGUs. The performance standards for existing EGUs, known as the EPA Clean Power Plan, were challenged by petitioners and stayed by the U.S. Supreme Court in February 2016 pending final review by the courts. On October 10, 2017, the EPA, under a new administration, proposed to rescind the Clean Power Plan, and in August 2018, the EPA proposed revised emission guidelines for GHGs from existing EGUs. On June 19, 2019, the EPA Administrator officially repealed the Clean Power Plan and finalized its replacement, named the ACE rule. The ACE rule was vacated and remanded back to the EPA in a D.C. Circuit Court decision on January 19, 2021. The next steps taken by the EPA with respect to regulation of GHGs from EGUs is uncertain. Regardless of future rules, DTE Energy remains committed for its electric utility operations to reduce carbon emissions 32% by 2023, 50% by 2030, and 80% by 2040 from 2005 carbon emissions levels, and its goal of net zero emissions for its electric utility operations by 2050.

In addition to the GHG standards for existing EGUs, in December 2018, the EPA issued proposed revisions to the carbon dioxide performance standards for new, modified, or reconstructed fossil-fuel fired EGUs. The carbon standards for new sources are not expected to have a material impact on DTE Electric, since DTE Electric has no plans to build new coal-fired generation and any potential new gas generation will be able to comply with the standards.

Pending or future legislation or other regulatory actions could have a material impact on DTE Electric's operations and financial position and the rates charged to its customers. Impacts include expenditures for environmental equipment beyond what is currently planned, financing costs related to additional capital expenditures, the purchase of emission credits from market sources, higher costs of purchased power, and the retirement of facilities where control equipment is not economical. DTE Electric would seek to recover these incremental costs through increased rates charged to its utility customers, as authorized by the MPSC.

Water — In response to an EPA regulation, DTE Electric was required to examine alternatives for reducing the environmental impacts of the cooling water intake structures at several of its facilities. Based on the results of completed studies and expected future studies, DTE Electric may be required to install technologies to reduce the impacts of the water intake structures. A final rule became effective in October 2014. The final rule requires studies to be completed and submitted as part of the NPDES permit application process to determine the type of technology needed to reduce impacts to fish. DTE Electric has initiated the process of completing the required studies. Final compliance for the installation of any required technology will be determined by the state on a case by case, site specific basis. DTE Electric is currently evaluating the compliance options and working with the State of Michigan on evaluating whether any controls are needed. These evaluations/studies may require modifications to some existing intake structures. It is not possible to quantify the impact of this rulemaking at this time.

Contaminated and Other Sites — Prior to the construction of major interstate natural gas pipelines, gas for heating and other uses was manufactured locally from processes involving coal, coke, or oil. The facilities, which produced gas, have been designated as MGP sites. DTE Electric conducted remedial investigations at contaminated sites, including three former MGP sites. Cleanup of one of the MGP sites is complete, and the site is closed. The investigations have revealed contamination related to the by-products of gas manufacturing at each MGP site. In addition to the MGP sites, DTE Electric is also in the process of cleaning up other contaminated sites, including the area surrounding an ash landfill, electrical distribution substations, electric generating power plants, and underground and above ground storage tank locations. The findings of these investigations indicated that the estimated cost to remediate these sites is expected to be incurred over the next several years. At June 30, 2021 and December 31, 2020, DTE Electric had $10 million accrued for remediation. These costs are not discounted to their present value. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Electric’s financial position and cash flows. DTE Electric believes the likelihood of a material change to the accrued amount is remote based on current knowledge of the conditions at each site.

Coal Combustion Residuals and Effluent Limitations Guidelines — A final EPA rule for the disposal of coal combustion residuals, commonly known as coal ash, became effective in October 2015, and was revised in October 2016, July 2018, September 2020, and November 2020. The rule is based on the continued listing of coal ash as a non-hazardous waste and relies on various self-implementation design and performance standards. DTE Electric owns and operates three permitted engineered coal ash storage facilities to dispose of coal ash from coal-fired power plants and operates a number of smaller impoundments at its power plants subject to certain provisions in the CCR rule. At certain facilities, the rule currently requires ongoing sampling and testing of monitoring wells, compliance with groundwater standards, and the closure of basins at the end of the useful life of the associated power plant.

On September 28, 2020, the CCR rule "A Holistic Approach to Closure Part A: Deadline to Initiate Closure and Enhancing Public Access to Information" became effective and establishes April 11, 2021 as the new deadline for all unlined impoundments (including units previously classified as "clay-lined") to initiate closure. Additionally, the rule amends certain reporting requirements and CCR website requirements. On November 12, 2020, an additional revision to the CCR Rule "A Holistic Approach to Closure Part B: Alternate Demonstration for Unlined Surface Impoundments" was published in the Federal Register that provides a process to determine if certain unlined impoundments consist of an alternative liner system that may be as protective as the current liners specified in the CCR rule, and therefore may continue to operate. DTE Electric has submitted applications to the EPA that support continued use of all impoundments through their active lives. The forced closure date of April 11, 2021 is effectively delayed while the EPA's review looks to extend beyond this date.

At the State level, legislation was signed by the Governor in December 2018 and provides for further regulation of the CCR program in Michigan. Additionally, the bill provides the basis of a CCR program that EGLE has submitted to the EPA for approval to fully regulate the CCR program in Michigan in lieu of a Federal permit program.

In October 2020, the EPA published in the Federal Register the final version of the ELG Reconsideration Rule which updates the 2015 ELG Rule (2015 Rule). The Reconsideration Rule re-establishes the technology-based effluent limitations guidelines and standards applicable to flue gas desulfurization (FGD) wastewater and bottom ash transport water. The EPA set the applicability dates for bottom ash transport water and FGD wastewater retrofits to be "as soon as possible" beginning October 13, 2021 and no later than December 31, 2025. Compliance schedules for individual facilities and individual waste streams are determined through issuance of new NPDES permits by the State of Michigan. The State of Michigan has issued a NPDES permit for the Belle River Power Plant establishing a compliance deadline of December 31, 2021 based on the 2015 Rule. Due to completion of the Reconsideration Rule in 2020, the compliance deadlines within the NPDES permit for Belle River Power Plant will be revised accordingly. No new permits that would require ELG compliance have been issued for other facilities, consequently no compliance timelines have been established.

On April 12, 2017, the EPA granted a petition for reconsideration of the 2015 ELG Rule. The EPA also signed an administrative stay of the 2015 ELG Rule’s compliance deadlines for fly ash transport water, bottom ash transport water, and FGD wastewater, among others. On June 6, 2017, the EPA published in the Federal Register a proposed rule (Postponement Rule) to postpone certain applicable deadlines within the 2015 ELG rule. The Postponement Rule was published on September 18, 2017. The Postponement Rule nullified the administrative stay but also extended the earliest compliance deadlines for only FGD wastewater and bottom ash transport water until November 1, 2020 in order for the EPA to propose and finalize a new ruling. On October 13, 2020, the EPA finalized the ELG Reconsideration Rule which revised the regulations from the 2015 ELG rule. The Reconsideration Rule revises requirements for two specific waste streams produced by steam electric power plants: FGD wastewater and bottom ash transport water. The Reconsideration Rule also provides additional compliance opportunities by finalizing low utilization and cessation of coal burning subcategories. The Reconsideration Rule provides new opportunities for DTE Electric to evaluate existing ELG compliance strategies and make any necessary adjustments to ensure full compliance with the ELGs in a cost-effective manner.

Air — In June 2020, DTE Energy expanded its net zero goal to include its gas utility operations by committing to reduce greenhouse gas emissions to net zero by 2050 from procurement of natural gas through delivery. As part of DTE Energy's 2050 net zero commitment, DTE Gas launched its CleanVision Natural Gas Balance program in January 2021 that offers customers a way to reduce their carbon footprint using carbon offsets and renewable natural gas. The carbon offset program is focused on protecting Michigan forests that naturally absorb carbon dioxide.

Contaminated and Other Sites — DTE Gas owns or previously owned 14 former MGP sites. Investigations have revealed contamination related to the by-products of gas manufacturing at each site. Cleanup of eight of the MGP sites is complete, and the sites are closed. DTE Gas has also completed partial closure of four additional sites. Cleanup activities associated with the remaining sites will continue over the next several years. The MPSC has established a cost deferral and rate recovery mechanism for investigation and remediation costs incurred at former MGP sites. In addition to the MGP sites, DTE Gas is also in the process of cleaning up other contaminated sites, including gate stations, gas pipeline releases, and underground storage tank locations. As of June 30, 2021 and December 31, 2020, DTE Gas had $23 million and $24 million, respectively, accrued for remediation. These costs are not discounted to their present value. Any change in assumptions, such as remediation techniques, nature and extent of contamination, and regulatory requirements, could impact the estimate of remedial action costs for the sites and affect DTE Gas' financial position and cash flows. DTE Gas anticipates the cost amortization methodology approved by the MPSC, which allows for amortization of the MGP costs over a ten-year period beginning with the year subsequent to the year the MGP costs were incurred, will prevent the associated investigation and remediation costs from having a material adverse impact on DTE Gas' results of operations.

In March 2019, the EPA issued an FOV to EES Coke, the Michigan coke battery facility that is a wholly-owned subsidiary of DTE Energy, alleging that the 2008 and 2014 permits issued by EGLE did not comply with the Clean Air Act. In September 2020, the EPA issued another FOV alleging EES Coke's 2018 and 2019 SO2 emissions exceeded projections and hence violated non-attainment new source review requirements. EES Coke evaluated the EPA's alleged violations and believes that the permits approved by EGLE complied with the Clean Air Act. EES Coke also responded to the EPA's September 2020 allegations demonstrating its actual emissions are compliant with non-attainment new source review requirements. Discussions with the EPA are ongoing. At the present time, DTE Energy cannot predict the outcome or financial impact of this FOV.

In 2010, the EPA finalized a new one-hour SO2 ambient air quality standard that requires states to submit plans and associated timelines for non-attainment areas that demonstrate attainment with the new SO2 standard in phases. Phase 1 addresses non-attainment areas designated based on ambient monitoring data. Phase 2 addresses non-attainment areas with large sources of SO2 and modeled concentrations exceeding the National Ambient Air Quality Standards for SO2. Phase 3 addresses smaller sources of SO2 with modeled or monitored exceedances of the new SO2 standard.

Michigan's Phase 1 non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Modeling runs by EGLE suggest that emission reductions may be required by significant sources of SO2 emissions in these areas, including DTE Electric power plants and DTE Energy's Michigan coke battery facility. As part Michigan's SIP process, DTE Energy has worked with EGLE to develop air permits reflecting significant SO2 emission reductions that, in combination with other non-DTE Energy sources' emission reduction strategies, will help the state attain the standard and sustain its attainment. The Michigan SIP was completed and submitted to the EPA on May 31, 2016 and supplemented on June 30, 2016. On March 19, 2021, the EPA published in the Federal Register partial approval and partial disapproval of Michigan's Detroit SO2 non-attainment area plan. The partial disapproval does not appear to impact DTE's sources and further discussions are underway with the EPA to finalize the plan. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of any further emissions reductions that may be required from DTE's facilities at this time.

DTE Energy discontinued the operations of its synthetic fuel production facilities throughout the United States as of December 31, 2007. DTE Energy provided certain guarantees and indemnities in conjunction with the sales of interests in its synfuel facilities. The guarantees cover potential commercial, environmental, oil price, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at June 30, 2021 was approximately $400 million. Payment under these guarantees is considered remote.

DTE Energy has provided certain guarantees and indemnities in conjunction with the sales of interests in or lease of its REF facilities. The guarantees cover potential commercial, environmental, and tax-related obligations that will survive until 90 days after expiration of all applicable statutes of limitations. DTE Energy estimates that its maximum potential liability under these guarantees at June 30, 2021 was $617 million. Payments under these guarantees are considered remote.

In certain limited circumstances, the Registrants enter into contractual guarantees. The Registrants may guarantee another entity’s obligation in the event it fails to perform and may provide guarantees in certain indemnification agreements. Finally, the Registrants may provide indirect guarantees for the indebtedness of others. DTE Energy’s guarantees are not individually material with maximum potential payments totaling $50 million at June 30, 2021. Payments under these guarantees are considered remote.

The Registrants are periodically required to obtain performance surety bonds in support of obligations to various governmental entities and other companies in connection with its operations. As of June 30, 2021, DTE Energy had $176 million of performance bonds outstanding, including $120 million for DTE Electric. In the event that such bonds are called for nonperformance, the Registrants would be obligated to reimburse the issuer of the performance bond. The Registrants are released from the performance bonds as the contractual performance is completed and does not believe that a material amount of any currently outstanding performance bonds will be called.

In July 2019, DTE Energy, as lender, entered into a revolving term credit facility with Vector, as borrower, in the amount of C$70 million. The credit facility was executed in response to the passage of Canadian regulations requiring oil and gas pipelines to demonstrate their financial ability to respond to a catastrophic event and exists for the sole purpose of satisfying these regulations. Vector may only draw upon the facility if the funds are required to respond to a catastrophic event. The maximum potential payment under the line of credit at June 30, 2021 was $56 million. On July 7, 2021 and in conjunction with the separation of DT Midstream, DTE Energy transferred the credit facility to DT Midstream and DT Midstream assumed the lender role under the credit facility.

There are several bargaining units for DTE Energy subsidiaries' approximate 5,200 represented employees, including DTE Electric's approximately 2,700 represented employees. This represents 49% and 57% of DTE Energy's and DTE Electric's total employees, respectively. The majority of the represented employees are under contracts that expire in 2027.

Utility capital expenditures, expenditures for non-utility businesses, and contributions to equity method investees will be approximately $3.9 billion and $3.0 billion in 2021 for DTE Energy and DTE Electric, respectively. The Registrants have made certain commitments in connection with the estimated 2021 annual capital expenditures and contributions to equity method investees.

DTE Energy Trading was the sole supplier of power for Brilliant Energy, LLC ("Brilliant"), a load serving entity and competitive retailer in ERCOT. During March 2021, Brilliant filed a voluntary petition for bankruptcy protection under Chapter 7 of the Bankruptcy Code. Subsequently, the bankruptcy court authorized a Trustee to continue managing Brilliant’s business to preserve any remaining value for their creditors and begin an orderly wind-down of Brilliant’s operations.

In June 2021, DTE Energy Trading completed the transfer of service for all of Brilliant's customer contracts to utilities in the ERCOT market and has no further service responsibilities related to Brilliant. For pre-petition receivables that were reserved during the first quarter 2021, approximately $9 million remains reserved as of June 30, 2021. Other pre-petition receivables of approximately $3 million were recovered during the second quarter 2021 and uncollectible expense was reversed. The remaining wind-down activities are expected to be completed in the third quarter 2021. DTE Energy does not believe there is any additional risk related to this bankruptcy.

In 2021, the COVID-19 pandemic has continued to impact DTE Electric sales volumes. As businesses have maintained certain remote operations, related sales volumes have been lower for commercial and industrial customers and higher for residential customers as compared to historical volumes before the pandemic. This impact contributed to a net reduction in DTE Electric sales, but has been offset by favorable rate mix.

In 2020, COVID-19 also resulted in incremental costs at our utilities related to personal protective equipment and other health and safety-related matters, as well as lower volumes for certain companies within the Power and Industrial Projects segment. For the three and six months ended June 30, 2021, however, there has not been any significant impact to the Registrants' Consolidated Financial Statements.

In consideration of the above factors and all other current and expected impacts to the Registrants' performance and cash flows resulting from the COVID-19 pandemic, there have been no material adjustments or reserves deemed necessary as of June 30, 2021. The Registrants cannot predict the future impacts of the COVID-19 pandemic on the Consolidated Financial Statements, as developments involving COVID-19 and its related effects on economic and operating conditions remain highly uncertain.

The Registrants are involved in certain other legal, regulatory, administrative, and environmental proceedings before various courts, arbitration panels, and governmental agencies concerning claims arising in the ordinary course of business. These proceedings include certain contract disputes, additional environmental reviews and investigations, audits, inquiries from various regulators, and pending judicial matters. The Registrants cannot predict the final disposition of such proceedings. The Registrants regularly review legal matters and record provisions for claims that they can estimate and are considered probable of loss. The resolution of these pending proceedings is not expected to have a material effect on the Registrants' Consolidated Financial Statements in the periods they are resolved.