Commitments and Contingencies	9 Months Ended
Sep. 30, 2015
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 sulfur dioxide and nitrogen oxides. The EPA and the State of Michigan have 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 nitrogen oxide, sulfur dioxide, mercury and other emissions. Additional rulemakings are expected over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides and hazardous air pollutants. The Cross State Air Pollution Rule (CSAPR), required further reductions of sulfur dioxide and nitrogen oxides emissions beginning in January 2015. DTE Electric expects to meet its obligations under CSAPR. However, portions of CSAPR are being reviewed by the Court of Appeals for the D.C. District and any financial impact related to this review cannot be predicted at this time. The Mercury and Air Toxics Standards (MATS) rule, formerly known as the Electric Generating Unit Maximum Achievable Control Technology (EGU MACT) Rule was finalized in December 2011. The MATS rule requires reductions of mercury and other hazardous air pollutants beginning in April 2015. DTE Electric has requested and been granted compliance date extensions for all relevant units to April 2016. DTE Electric has tested several technologies as MATS compliance alternatives to Flue Gas Desulfurization (FGD) systems to determine technological and economic feasibility. Dry Sorbent Injection (DSI) and Activated Carbon Injection (ACI) technologies were deemed feasible and their implementation will allow units that would not have been economical for FGD installations to continue operation in compliance with MATS. In November 2014, the U.S. Supreme Court agreed to review a challenge to the MATS rule based on a narrowly focused question of how the EPA considered costs in regulating air pollutants emitted by electric utilities. In June 2015, the U.S. Supreme Court reversed the decision of the Court of Appeals for the D.C. District and remanded the MATS rule to the Court of Appeals for further consideration based on their decision that the EPA must consider costs prior to deciding to regulate under the provisions of the Clean Air Act. DTE Electric does not expect this decision to have a material effect on its compliance plans at this time. 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 on October 1, 2015. DTE Electric cannot predict the financial impact of the revised ozone standards at this time. In July 2009, DTE Energy received a NOV/FOV from the EPA alleging, among other things, that five DTE Electric power plants violated New Source Performance standards, Prevention of Significant Deterioration requirements, and operating permit requirements under the Clean Air Act. In June 2010, the EPA issued a NOV/FOV making similar allegations related to a project and outage at Unit 2 of the Monroe Power Plant. In March 2013, DTE Energy received a supplemental NOV from the EPA relating to the July 2009 NOV/FOV. The supplemental NOV alleged additional violations relating to the New Source Review provisions under the Clean Air Act, among other things. In August 2010, the U.S. Department of Justice, at the request of the EPA, brought a civil suit in the U.S. District Court for the Eastern District of Michigan against DTE Energy and DTE Electric, related to the June 2010 NOV/FOV and the outage work performed at Unit 2 of the Monroe Power Plant, but not relating to the July 2009 NOV/FOV. Among other relief, the EPA requested the court to require DTE Electric to install and operate the best available control technology at Unit 2 of the Monroe Power Plant. Further, the EPA requested the court to issue a preliminary injunction to require DTE Electric to (i) begin the process of obtaining the necessary permits for the Monroe Unit 2 modification and (ii) offset the pollution from Monroe Unit 2 through emissions reductions from DTE Electric's fleet of coal-fired power plants until the new control equipment is operating. In August 2011, the U.S. District Court judge granted DTE Energy's motion for summary judgment in the civil case, dismissing the case and entering judgment in favor of DTE Energy and DTE Electric. In October 2011, the EPA caused to be filed a Notice of Appeal to the Court of Appeals for the Sixth Circuit. In March 2013, the Court of Appeals remanded the case to the U.S. District Court for review of the procedural component of the New Source Review notification requirements. In September 2013, the EPA caused to be filed a motion seeking leave to amend their complaint regarding the June 2010 NOV/FOV adding additional claims related to outage work performed at the Trenton Channel and Belle River power plants as well as additional claims related to work performed at the Monroe Power Plant. In addition, the Sierra Club caused to be filed a motion to add a claim regarding the River Rouge Power Plant. In March 2014, the U.S. District Court judge granted again DTE Energy's motion for summary judgment dismissing the civil case related to Monroe Unit 2. In April 2014, the U.S. District Court judge granted motions filed by the EPA and the Sierra Club to amend their New Source Review complaint adding additional claims for Monroe Units 1, 2 and 3, Belle River Units 1 and 2, Trenton Channel Unit 9 and denied the claims related to River Rouge Power Plant that were brought by the Sierra Club. In June 2014, the EPA filed a motion requesting certification for appeal of the March 2014 summary judgment decision. In October 2014, the EPA and the U.S. Department of Justice filed the anticipated notice of appeal of the U.S. District Court judge's dismissal of the Monroe Unit 2 case. The amended New Source Review claims are all stayed until the appeal is resolved by the Court of Appeals for the Sixth Circuit. Oral arguments for the appeal are scheduled for December 2015. The Registrants believe that the plants and generating units identified by the EPA and the Sierra Club have complied with all applicable federal environmental regulations. Depending upon the outcome of discussions with the EPA regarding the two NOVs/FOVs, DTE Electric could be required to install additional pollution control equipment at some or all of the power plants in question, implement early retirement of facilities where control equipment is not economical, engage in supplemental environmental programs, and/or pay fines. The Registrants cannot predict the financial impact or outcome of this matter, or the timing of its resolution. To comply with air pollution requirements, DTE Electric spent approximately $2.2 billion through 2014. DTE Electric estimates making capital expenditures of approximately $100 million in 2015 and approximately $50 million of additional capital expenditures in 2016 based on current regulations. Water — In response to an EPA regulation, DTE Electric would be 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 was issued in May 2014. The final rule specifies a time period exceeding three years to complete studies to determine the type of technology needed to reduce impacts to fish. Final compliance for the installation of any required technology will be determined by each state on a case by case 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. In April 2013, the EPA proposed revised steam electric effluent guidelines regulating wastewater streams from coal-fired power plants including multiple possible options for compliance. The rules were finalized on September 30, 2015 and are expected to be effective by the end of 2015. It is not possible at this time to quantify the impacts of the final rules. 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. 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 aboveground 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 September 30, 2015 and December 31, 2014, DTE Electric had $9 million and $10 million accrued for remediation, respectively. 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 Residual Rule — In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule becomes effective in October 2015. 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. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks. Costs associated with the building of new facilities over the next seven years are estimated to be approximately $190 million. See Note 5 to the Consolidated Financial Statements, "Asset Retirement Obligations", for estimated costs of closure of old facilities. DTE Gas 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 five of the MGP sites is complete and the sites are closed. DTE Gas has also completed partial closure of two 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 September 30, 2015 and December 31, 2014, DTE Gas had $23 million and $24 million accrued for remediation, respectively. 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’s 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 environmental costs from having a material adverse impact on DTE Gas’s 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. The Michigan coke battery facility received and responded to information requests from the EPA that resulted in the issuance of a NOV in June 2007 alleging potential maximum achievable control technologies and new source review violations. The EPA is in the process of reviewing DTE Energy’s position of demonstrated compliance and has not initiated escalated enforcement. At this time, DTE Energy cannot predict the impact of this issue. Furthermore, the Michigan coke battery facility is the subject of an investigation by the MDEQ concerning visible emissions readings that resulted from DTE Energy self reporting to MDEQ questionable activities by an employee of a contractor hired by DTE Energy to perform the visible emissions readings. At this time, DTE Energy cannot predict the impact of this investigation. DTE Energy received two NOVs from the Pennsylvania Department of Environmental Protection (PADEP) in 2010 alleging violations of the permit for the Pennsylvania coke battery facility in connection with coal pile storm water runoff. DTE Energy settled the alleged violations by implementing best management practices to address the issues and repair/upgrade their wastewater treatment plant. DTE Energy received a construction permit to upgrade its existing waste water treatment system and is currently seeking a permit from the PADEP to further upgrade its wastewater treatment technology to biological treatment. DTE Energy spent approximately $1 million on the existing waste water treatment system to comply with existing water discharge requirements and to upgrade its coal pile storm water runoff management program. DTE Energy expects to also spend up to an additional $15 million over the next few years to complete its upgrade of the treatment technology to biological treatment in order to meet future regulatory requirements and gain other operational improvement savings. DTE Energy received an NOV from the Allegheny County (PA) Health Department pertaining to excessive opacity readings from fugitive sources in excess of its standards for the Pennsylvania coke battery facility. Fugitive sources at the plant are in full compliance with the applicable Federal Opacity Standards. DTE Energy agreed to a Consent Order and Agreement with Allegheny County pursuant to which DTE Energy paid a fine of $300,000 and will spend $300,000 for a supplemental environmental project. In May 2014, the Group Against Smog & Pollution (GASP) filed a complaint alleging that DTE Energy's coke battery facility in Pennsylvania was in violation of visible emissions limits under the Federal Clean Air Act and/or Article XXI of the Allegheny County (PA) Health Department's Rules and Regulations. DTE Energy believed that the GASP suit was without merit and filed a motion to dismiss in July 2014. In March 2015, the U.S. District Court granted DTE Energy's motion for dismissal. In April 2015, GASP filed a notice of appeal. At the present time, DTE Energy cannot predict the financial impact or outcome of this matter, or the timing of its resolution. Other In 2010, the EPA finalized a new 1-hour sulfur dioxide ambient air quality standard that requires states to submit plans for non-attainment areas to be in compliance by 2018. Michigan's non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Modeling runs by the MDEQ suggest that emission reductions may be required by significant sources of sulfur dioxide emissions in these areas, including DTE Electric power plants and DTE Energy's Michigan coke battery facility. As part of the state implementation plan process, DTE Energy has worked with MDEQ to develop air permits reflecting significant SO2 emission reductions that, in combination with other non-DTE Energy sources emission reduction startegies, will help the State attain the standard and sustain its attainment. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of the final required emissions reductions at this time. Nuclear Operations Property Insurance DTE Electric maintains property insurance policies specifically for the Fermi 2 plant. These policies cover such items as replacement power and property damage. NEIL is the primary supplier of the insurance policies. DTE Electric maintains a policy for extra expenses, including replacement power costs necessitated by Fermi 2’s unavailability due to an insured event. This policy has a 12-week waiting period and provides an aggregate $490 million of coverage over a three-year period. DTE Electric has $1.5 billion in primary coverage and $1.25 billion of excess coverage for stabilization, decontamination, debris removal, repair and/or replacement of property and decommissioning. The combined coverage limit for total property damage is $2.75 billion. The total limit for property damage for non-nuclear events is $2 billion and an aggregate of $328 million of coverage for extra expenses over a two-year period. On January 13, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed, extending TRIA through December 31, 2020. For multiple terrorism losses caused by acts of terrorism not covered under the TRIA occurring within one year after the first loss from terrorism, the NEIL policies would make available to all insured entities up to $3.2 billion, plus any amounts recovered from reinsurance, government indemnity, or other sources to cover losses. Under NEIL policies, DTE Electric could be liable for maximum assessments of up to approximately $46 million per event if the loss associated with any one event at any nuclear plant should exceed the accumulated funds available to NEIL. Public Liability Insurance As required by federal law, DTE Electric maintains $375 million of public liability insurance for a nuclear incident. For liabilities arising from a terrorist act outside the scope of TRIA, the policy is subject to one industry aggregate limit of $300 million. Further, under the Price-Anderson Amendments Act of 2005, deferred premium charges up to $127 million could be levied against each licensed nuclear facility, but not more than $19 million per year per facility. Thus, deferred premium charges could be levied against all owners of licensed nuclear facilities in the event of a nuclear incident at any of these facilities. Nuclear Fuel Disposal Costs In accordance with the Federal Nuclear Waste Policy Act of 1982, DTE Electric has a contract with the DOE for the future storage and disposal of spent nuclear fuel from Fermi 2 that required DTE Electric to pay the DOE a fee of 1 mill per kWh of Fermi 2 electricity generated and sold. The fee was a component of nuclear fuel expense. The DOE's Yucca Mountain Nuclear Waste Repository program for the acceptance and disposal of spent nuclear fuel was terminated in 2011. DTE Electric is a party in the litigation against the DOE for both past and future costs associated with the DOE's failure to accept spent nuclear fuel under the timetable set forth in the Federal Nuclear Waste Policy Act of 1982. In July 2012, DTE Electric executed a settlement agreement with the federal government for costs associated with the DOE's delay in acceptance of spent nuclear fuel from Fermi 2 for permanent storage. The settlement agreement, including extensions, provides for a claims process and payment of delay-related costs experienced by DTE Electric through 2016. DTE Electric's claims are being settled and paid on a timely basis. The settlement proceeds reduce the cost of the dry cask storage facility assets and provide reimbursement for related operating expenses. The 1 mill per kWh DOE fee was reduced to zero effective May 16, 2014. DTE Electric currently employs a spent nuclear fuel storage strategy utilizing a fuel pool and a newly completed dry cask storage facility. The dry cask storage facility is expected to provide sufficient spent fuel storage capability for the life of the plant as defined by the original operating license. The federal government continues to maintain its legal obligation to accept spent nuclear fuel from Fermi 2 for permanent storage. Issues relating to long-term waste disposal policy and to the disposition of funds contributed by DTE Electric ratepayers to the federal waste fund await future governmental action. 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 and 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 September 30, 2015 is approximately $850 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 and 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 September 30, 2015 is approximately $238 million. Payment under these guarantees is 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 $66 million at September 30, 2015. Payment under these guarantees is considered remote. DTE Energy is 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 September 30, 2015, DTE Energy had approximately $49 million of performance bonds outstanding. In the event that such bonds are called for nonperformance, DTE Energy would be obligated to reimburse the issuer of the performance bond. DTE Energy is 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. Labor Contracts There are several bargaining units for DTE Energy's approximately 4,900 represented employees, including DTE Electric's approximately 2,600 represented employees. The majority of the represented employees are under contracts that expire in 2016 and 2017. Purchase Commitments As of September 30, 2015, the Registrants were party to numerous long-term purchase commitments relating to a variety of goods and services required for their businesses. These agreements primarily consist of fuel supply commitments and renewable energy contracts for the Registrants, as well as energy trading contracts for DTE Energy. DTE Energy estimates that these commitments will be approximately $7.4 billion from 2015 through 2051. DTE Electric estimates that these commitments will be approximately $2.2 billion from 2015 through 2033. In addition, the Registrants have made certain commitments in connection with 2015 annual capital expenditures and contributions to equity method investees that are expected to be up to $2.5 billion for DTE Energy and $1.8 billion for DTE Electric. Bankruptcies Certain of the Registrants' customers and suppliers have filed for bankruptcy protection under the U.S. Bankruptcy Code. The Registrants regularly review contingent matters relating to these customers and suppliers and their purchase and sale contracts and record provisions for amounts considered at risk of probable loss. The Registrants believe their accrued amounts are adequate for probable loss. Michigan Sales and Use Tax Litigation In 2010, the Michigan Department of Treasury finalized a sales and use tax audit of DTE Electric for the period from January 2003 to September 2006. It determined that DTE Electric’s electric distribution equipment was not eligible for an industrial-processing exemption and therefore was subject to the use tax. DTE Electric paid the tax for the period under audit and filed a claim in the Michigan Court of Claims disputing the tax determination. DTE Electric has continued to apply the industrial-processing exemption for the years subsequent to 2006. The Michigan Court of Claims found in favor of DTE Electric, and that determination was subsequently appealed to the Michigan Supreme Court. In July 2015, the Michigan Supreme Court issued an opinion finding that DTE Electric was eligible for a partial industrial-processing exemption on its electric distribution equipment based on the proportion of exempt use of that equipment. The Supreme Court reversed the lower court decision in part and remanded the case to the Michigan Court of Claims. DTE Electric expects this issue and the timing of any potential tax refunds or assessments to be resolved not later than 2016. DTE Electric considers the likelihood of a material unfavorable outcome to be remote. 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' operations or 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.

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 sulfur dioxide and nitrogen oxides. The EPA and the State of Michigan have 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 nitrogen oxide, sulfur dioxide, mercury and other emissions. Additional rulemakings are expected over the next few years which could require additional controls for sulfur dioxide, nitrogen oxides and hazardous air pollutants.

The Cross State Air Pollution Rule (CSAPR), required further reductions of sulfur dioxide and nitrogen oxides emissions beginning in January 2015. DTE Electric expects to meet its obligations under CSAPR. However, portions of CSAPR are being reviewed by the Court of Appeals for the D.C. District and any financial impact related to this review cannot be predicted at this time.

The Mercury and Air Toxics Standards (MATS) rule, formerly known as the Electric Generating Unit Maximum Achievable Control Technology (EGU MACT) Rule was finalized in December 2011. The MATS rule requires reductions of mercury and other hazardous air pollutants beginning in April 2015. DTE Electric has requested and been granted compliance date extensions for all relevant units to April 2016. DTE Electric has tested several technologies as MATS compliance alternatives to Flue Gas Desulfurization (FGD) systems to determine technological and economic feasibility. Dry Sorbent Injection (DSI) and Activated Carbon Injection (ACI) technologies were deemed feasible and their implementation will allow units that would not have been economical for FGD installations to continue operation in compliance with MATS. In November 2014, the U.S. Supreme Court agreed to review a challenge to the MATS rule based on a narrowly focused question of how the EPA considered costs in regulating air pollutants emitted by electric utilities. In June 2015, the U.S. Supreme Court reversed the decision of the Court of Appeals for the D.C. District and remanded the MATS rule to the Court of Appeals for further consideration based on their decision that the EPA must consider costs prior to deciding to regulate under the provisions of the Clean Air Act. DTE Electric does not expect this decision to have a material effect on its compliance plans at this time.

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 on October 1, 2015. DTE Electric cannot predict the financial impact of the revised ozone standards at this time.

In July 2009, DTE Energy received a NOV/FOV from the EPA alleging, among other things, that five DTE Electric power plants violated New Source Performance standards, Prevention of Significant Deterioration requirements, and operating permit requirements under the Clean Air Act. In June 2010, the EPA issued a NOV/FOV making similar allegations related to a project and outage at Unit 2 of the Monroe Power Plant. In March 2013, DTE Energy received a supplemental NOV from the EPA relating to the July 2009 NOV/FOV. The supplemental NOV alleged additional violations relating to the New Source Review provisions under the Clean Air Act, among other things.

In August 2010, the U.S. Department of Justice, at the request of the EPA, brought a civil suit in the U.S. District Court for the Eastern District of Michigan against DTE Energy and DTE Electric, related to the June 2010 NOV/FOV and the outage work performed at Unit 2 of the Monroe Power Plant, but not relating to the July 2009 NOV/FOV. Among other relief, the EPA requested the court to require DTE Electric to install and operate the best available control technology at Unit 2 of the Monroe Power Plant. Further, the EPA requested the court to issue a preliminary injunction to require DTE Electric to (i) begin the process of obtaining the necessary permits for the Monroe Unit 2 modification and (ii) offset the pollution from Monroe Unit 2 through emissions reductions from DTE Electric's fleet of coal-fired power plants until the new control equipment is operating. In August 2011, the U.S. District Court judge granted DTE Energy's motion for summary judgment in the civil case, dismissing the case and entering judgment in favor of DTE Energy and DTE Electric. In October 2011, the EPA caused to be filed a Notice of Appeal to the Court of Appeals for the Sixth Circuit. In March 2013, the Court of Appeals remanded the case to the U.S. District Court for review of the procedural component of the New Source Review notification requirements. In September 2013, the EPA caused to be filed a motion seeking leave to amend their complaint regarding the June 2010 NOV/FOV adding additional claims related to outage work performed at the Trenton Channel and Belle River power plants as well as additional claims related to work performed at the Monroe Power Plant. In addition, the Sierra Club caused to be filed a motion to add a claim regarding the River Rouge Power Plant. In March 2014, the U.S. District Court judge granted again DTE Energy's motion for summary judgment dismissing the civil case related to Monroe Unit 2. In April 2014, the U.S. District Court judge granted motions filed by the EPA and the Sierra Club to amend their New Source Review complaint adding additional claims for Monroe Units 1, 2 and 3, Belle River Units 1 and 2, Trenton Channel Unit 9 and denied the claims related to River Rouge Power Plant that were brought by the Sierra Club. In June 2014, the EPA filed a motion requesting certification for appeal of the March 2014 summary judgment decision. In October 2014, the EPA and the U.S. Department of Justice filed the anticipated notice of appeal of the U.S. District Court judge's dismissal of the Monroe Unit 2 case. The amended New Source Review claims are all stayed until the appeal is resolved by the Court of Appeals for the Sixth Circuit. Oral arguments for the appeal are scheduled for December 2015.

The Registrants believe that the plants and generating units identified by the EPA and the Sierra Club have complied with all applicable federal environmental regulations. Depending upon the outcome of discussions with the EPA regarding the two NOVs/FOVs, DTE Electric could be required to install additional pollution control equipment at some or all of the power plants in question, implement early retirement of facilities where control equipment is not economical, engage in supplemental environmental programs, and/or pay fines. The Registrants cannot predict the financial impact or outcome of this matter, or the timing of its resolution.

To comply with air pollution requirements, DTE Electric spent approximately $2.2 billion through 2014. DTE Electric estimates making capital expenditures of approximately $100 million in 2015 and approximately $50 million of additional capital expenditures in 2016 based on current regulations.

Water — In response to an EPA regulation, DTE Electric would be 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 was issued in May 2014. The final rule specifies a time period exceeding three years to complete studies to determine the type of technology needed to reduce impacts to fish. Final compliance for the installation of any required technology will be determined by each state on a case by case 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.

In April 2013, the EPA proposed revised steam electric effluent guidelines regulating wastewater streams from coal-fired power plants including multiple possible options for compliance. The rules were finalized on September 30, 2015 and are expected to be effective by the end of 2015. It is not possible at this time to quantify the impacts of the final rules.

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. 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 aboveground 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 September 30, 2015 and December 31, 2014, DTE Electric had $9 million and $10 million accrued for remediation, respectively. 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 Residual Rule — In April 2015, the EPA published a final rule for the disposal of coal combustion residuals, commonly known as coal ash. The rule becomes effective in October 2015. 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. At certain facilities, the rule requires the installation of monitoring wells, compliance with groundwater standards and the closure of basins at the end of the useful life of the associated power plant. At other facilities, the rule requires ash laden waters be moved from earthen basins to steel and concrete tanks. Costs associated with the building of new facilities over the next seven years are estimated to be approximately $190 million. See Note 5 to the Consolidated Financial Statements, "Asset Retirement Obligations", for estimated costs of closure of old facilities.

DTE Gas

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 five of the MGP sites is complete and the sites are closed. DTE Gas has also completed partial closure of two 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 September 30, 2015 and December 31, 2014, DTE Gas had $23 million and $24 million accrued for remediation, respectively. 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’s 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 environmental costs from having a material adverse impact on DTE Gas’s 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.

The Michigan coke battery facility received and responded to information requests from the EPA that resulted in the issuance of a NOV in June 2007 alleging potential maximum achievable control technologies and new source review violations. The EPA is in the process of reviewing DTE Energy’s position of demonstrated compliance and has not initiated escalated enforcement. At this time, DTE Energy cannot predict the impact of this issue. Furthermore, the Michigan coke battery facility is the subject of an investigation by the MDEQ concerning visible emissions readings that resulted from DTE Energy self reporting to MDEQ questionable activities by an employee of a contractor hired by DTE Energy to perform the visible emissions readings. At this time, DTE Energy cannot predict the impact of this investigation.

DTE Energy received two NOVs from the Pennsylvania Department of Environmental Protection (PADEP) in 2010 alleging violations of the permit for the Pennsylvania coke battery facility in connection with coal pile storm water runoff. DTE Energy settled the alleged violations by implementing best management practices to address the issues and repair/upgrade their wastewater treatment plant. DTE Energy received a construction permit to upgrade its existing waste water treatment system and is currently seeking a permit from the PADEP to further upgrade its wastewater treatment technology to biological treatment. DTE Energy spent approximately $1 million on the existing waste water treatment system to comply with existing water discharge requirements and to upgrade its coal pile storm water runoff management program. DTE Energy expects to also spend up to an additional $15 million over the next few years to complete its upgrade of the treatment technology to biological treatment in order to meet future regulatory requirements and gain other operational improvement savings.

DTE Energy received an NOV from the Allegheny County (PA) Health Department pertaining to excessive opacity readings from fugitive sources in excess of its standards for the Pennsylvania coke battery facility. Fugitive sources at the plant are in full compliance with the applicable Federal Opacity Standards. DTE Energy agreed to a Consent Order and Agreement with Allegheny County pursuant to which DTE Energy paid a fine of $300,000 and will spend $300,000 for a supplemental environmental project. In May 2014, the Group Against Smog & Pollution (GASP) filed a complaint alleging that DTE Energy's coke battery facility in Pennsylvania was in violation of visible emissions limits under the Federal Clean Air Act and/or Article XXI of the Allegheny County (PA) Health Department's Rules and Regulations. DTE Energy believed that the GASP suit was without merit and filed a motion to dismiss in July 2014. In March 2015, the U.S. District Court granted DTE Energy's motion for dismissal. In April 2015, GASP filed a notice of appeal. At the present time, DTE Energy cannot predict the financial impact or outcome of this matter, or the timing of its resolution.

Other

In 2010, the EPA finalized a new 1-hour sulfur dioxide ambient air quality standard that requires states to submit plans for non-attainment areas to be in compliance by 2018. Michigan's non-attainment area includes DTE Energy facilities in southwest Detroit and areas of Wayne County. Modeling runs by the MDEQ suggest that emission reductions may be required by significant sources of sulfur dioxide emissions in these areas, including DTE Electric power plants and DTE Energy's Michigan coke battery facility. As part of the state implementation plan process, DTE Energy has worked with MDEQ to develop air permits reflecting significant SO2 emission reductions that, in combination with other non-DTE Energy sources emission reduction startegies, will help the State attain the standard and sustain its attainment. Since several non-DTE Energy sources are also part of the proposed compliance plan, DTE Energy is unable to determine the full impact of the final required emissions reductions at this time.

Nuclear Operations

Property Insurance

DTE Electric maintains property insurance policies specifically for the Fermi 2 plant. These policies cover such items as replacement power and property damage. NEIL is the primary supplier of the insurance policies.

DTE Electric maintains a policy for extra expenses, including replacement power costs necessitated by Fermi 2’s unavailability due to an insured event. This policy has a 12-week waiting period and provides an aggregate $490 million of coverage over a three-year period.

DTE Electric has $1.5 billion in primary coverage and $1.25 billion of excess coverage for stabilization, decontamination, debris removal, repair and/or replacement of property and decommissioning. The combined coverage limit for total property damage is $2.75 billion. The total limit for property damage for non-nuclear events is $2 billion and an aggregate of $328 million of coverage for extra expenses over a two-year period.

On January 13, 2015, the Terrorism Risk Insurance Program Reauthorization Act of 2015 was signed, extending TRIA through December 31, 2020. For multiple terrorism losses caused by acts of terrorism not covered under the TRIA occurring within one year after the first loss from terrorism, the NEIL policies would make available to all insured entities up to $3.2 billion, plus any amounts recovered from reinsurance, government indemnity, or other sources to cover losses.

Under NEIL policies, DTE Electric could be liable for maximum assessments of up to approximately $46 million per event if the loss associated with any one event at any nuclear plant should exceed the accumulated funds available to NEIL.

Public Liability Insurance

As required by federal law, DTE Electric maintains $375 million of public liability insurance for a nuclear incident. For liabilities arising from a terrorist act outside the scope of TRIA, the policy is subject to one industry aggregate limit of $300 million. Further, under the Price-Anderson Amendments Act of 2005, deferred premium charges up to $127 million could be levied against each licensed nuclear facility, but not more than $19 million per year per facility. Thus, deferred premium charges could be levied against all owners of licensed nuclear facilities in the event of a nuclear incident at any of these facilities.

Nuclear Fuel Disposal Costs

In accordance with the Federal Nuclear Waste Policy Act of 1982, DTE Electric has a contract with the DOE for the future storage and disposal of spent nuclear fuel from Fermi 2 that required DTE Electric to pay the DOE a fee of 1 mill per kWh of Fermi 2 electricity generated and sold. The fee was a component of nuclear fuel expense. The DOE's Yucca Mountain Nuclear Waste Repository program for the acceptance and disposal of spent nuclear fuel was terminated in 2011. DTE Electric is a party in the litigation against the DOE for both past and future costs associated with the DOE's failure to accept spent nuclear fuel under the timetable set forth in the Federal Nuclear Waste Policy Act of 1982. In July 2012, DTE Electric executed a settlement agreement with the federal government for costs associated with the DOE's delay in acceptance of spent nuclear fuel from Fermi 2 for permanent storage. The settlement agreement, including extensions, provides for a claims process and payment of delay-related costs experienced by DTE Electric through 2016. DTE Electric's claims are being settled and paid on a timely basis. The settlement proceeds reduce the cost of the dry cask storage facility assets and provide reimbursement for related operating expenses. The 1 mill per kWh DOE fee was reduced to zero effective May 16, 2014.

DTE Electric currently employs a spent nuclear fuel storage strategy utilizing a fuel pool and a newly completed dry cask storage facility. The dry cask storage facility is expected to provide sufficient spent fuel storage capability for the life of the plant as defined by the original operating license.

The federal government continues to maintain its legal obligation to accept spent nuclear fuel from Fermi 2 for permanent storage. Issues relating to long-term waste disposal policy and to the disposition of funds contributed by DTE Electric ratepayers to the federal waste fund await future governmental action.

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 and 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 September 30, 2015 is approximately $850 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 and 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 September 30, 2015 is approximately $238 million. Payment under these guarantees is 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 $66 million at September 30, 2015. Payment under these guarantees is considered remote.

DTE Energy is 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 September 30, 2015, DTE Energy had approximately $49 million of performance bonds outstanding. In the event that such bonds are called for nonperformance, DTE Energy would be obligated to reimburse the issuer of the performance bond. DTE Energy is 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.

Labor Contracts

There are several bargaining units for DTE Energy's approximately 4,900 represented employees, including DTE Electric's approximately 2,600 represented employees. The majority of the represented employees are under contracts that expire in 2016 and 2017.

Purchase Commitments

As of September 30, 2015, the Registrants were party to numerous long-term purchase commitments relating to a variety of goods and services required for their businesses. These agreements primarily consist of fuel supply commitments and renewable energy contracts for the Registrants, as well as energy trading contracts for DTE Energy. DTE Energy estimates that these commitments will be approximately $7.4 billion from 2015 through 2051. DTE Electric estimates that these commitments will be approximately $2.2 billion from 2015 through 2033. In addition, the Registrants have made certain commitments in connection with 2015 annual capital expenditures and contributions to equity method investees that are expected to be up to $2.5 billion for DTE Energy and $1.8 billion for DTE Electric.

Bankruptcies

Certain of the Registrants' customers and suppliers have filed for bankruptcy protection under the U.S. Bankruptcy Code. The Registrants regularly review contingent matters relating to these customers and suppliers and their purchase and sale contracts and record provisions for amounts considered at risk of probable loss. The Registrants believe their accrued amounts are adequate for probable loss.

Michigan Sales and Use Tax Litigation

In 2010, the Michigan Department of Treasury finalized a sales and use tax audit of DTE Electric for the period from January 2003 to September 2006. It determined that DTE Electric’s electric distribution equipment was not eligible for an industrial-processing exemption and therefore was subject to the use tax. DTE Electric paid the tax for the period under audit and filed a claim in the Michigan Court of Claims disputing the tax determination. DTE Electric has continued to apply the industrial-processing exemption for the years subsequent to 2006.

The Michigan Court of Claims found in favor of DTE Electric, and that determination was subsequently appealed to the Michigan Supreme Court. In July 2015, the Michigan Supreme Court issued an opinion finding that DTE Electric was eligible for a partial industrial-processing exemption on its electric distribution equipment based on the proportion of exempt use of that equipment. The Supreme Court reversed the lower court decision in part and remanded the case to the Michigan Court of Claims. DTE Electric expects this issue and the timing of any potential tax refunds or assessments to be resolved not later than 2016. DTE Electric considers the likelihood of a material unfavorable outcome to be remote.

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' operations or 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.