Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2018

The Consolidated Financial Statements should be read in conjunction with the Combined Notes to Consolidated Financial Statements included in the combined DTE Energy and DTE Electric 2017 Annual Report on Form 10-K.

The accompanying Consolidated Financial Statements of the Registrants are prepared using accounting principles generally accepted in the United States of America. These accounting principles require management to use estimates and assumptions that impact reported amounts of assets, liabilities, revenues and expenses, and the disclosure of contingent assets and liabilities. Actual results may differ from the Registrants' estimates.

The Consolidated Financial Statements are unaudited but, in the Registrants' opinions include all adjustments necessary to present a fair statement of the results for the interim periods. All adjustments are of a normal recurring nature, except as otherwise disclosed in these Consolidated Financial Statements and Combined Notes to Consolidated Financial Statements. Financial results for this interim period are not necessarily indicative of results that may be expected for any other interim period or for the fiscal year ending December 31, 2018.

The information in these combined notes relates to each of the Registrants as noted in the Index of Combined Notes to Consolidated Financial Statements. However, DTE Electric does not make any representation as to information related solely to DTE Energy or the subsidiaries of DTE Energy other than itself.

Reclassification

Certain prior year balances for DTE Energy were reclassified to match the current year's Consolidated Financial Statements presentation.

Principles of Consolidation

The Registrants consolidate all majority-owned subsidiaries and investments in entities in which they have controlling influence. Non-majority owned investments are accounted for using the equity method when the Registrants are able to significantly influence the operating policies of the investee. When the Registrants do not influence the operating policies of an investee, the cost method is used. These Consolidated Financial Statements also reflect the Registrants' proportionate interests in certain jointly-owned utility plants. The Registrants eliminate all intercompany balances and transactions.

The Registrants evaluate whether an entity is a VIE whenever reconsideration events occur. The Registrants consolidate VIEs for which they are the primary beneficiary. If a Registrant is not the primary beneficiary and an ownership interest is held, the VIE is accounted for under the equity method of accounting. When assessing the determination of the primary beneficiary, a Registrant considers all relevant facts and circumstances, including: the power, through voting or similar rights, to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb the expected losses and/or the right to receive the expected returns of the VIE. The Registrants perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.

Legal entities within DTE Energy's Power and Industrial Projects segment enter into long-term contractual arrangements with customers to supply energy-related products or services. The entities are generally designed to pass-through the commodity risk associated with these contracts to the customers, with DTE Energy retaining operational and customer default risk. These entities generally are VIEs and consolidated when DTE Energy is the primary beneficiary. In addition, DTE Energy has interests in certain VIEs through which control of all significant activities is shared with partners, and therefore are accounted for under the equity method.

DTE Energy owns a 55% interest in SGG, which owns and operates midstream natural gas assets. SGG has contracts through which certain construction risk is designed to pass-through to the customers, with DTE Energy retaining operational and customer default risk. SGG is a VIE with DTE Energy as the primary beneficiary.

The Registrants have variable interests in NEXUS, which include DTE Energy's 50% ownership interest and DTE Electric's transportation services contract. NEXUS is a joint venture which owns a 256-mile pipeline to transport Utica and Marcellus shale gas to Ohio, Michigan, and Ontario market centers. NEXUS is a VIE as it has insufficient equity at risk to finance its activities. The Registrants are not the primary beneficiaries, as the power to direct significant activities is shared between the owners of the equity interests. DTE Energy accounts for its ownership interest in NEXUS under the equity method.

The Registrants hold ownership interests in certain limited partnerships. The limited partnerships include investment funds which support regional development and economic growth, as well as an operational business providing energy-related products. These entities are generally VIEs as a result of certain characteristics of the limited partnership voting rights. The ownership interests are accounted for under the equity method as the Registrants are not the primary beneficiaries.

DTE Energy has variable interests in VIEs through certain of its long-term purchase and sale contracts. DTE Electric has variable interests in VIEs through certain of its long-term purchase contracts. As of September 30, 2018, the carrying amount of assets and liabilities in DTE Energy's Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase and sale contracts are predominantly related to working capital accounts and generally represent the amounts owed by or to DTE Energy for the deliveries associated with the current billing cycle under the contracts. As of September 30, 2018, the carrying amount of assets and liabilities in DTE Electric's Consolidated Statements of Financial Position that relate to its variable interests under long-term purchase contracts are predominantly related to working capital accounts and generally represent the amounts owed by DTE Electric for the deliveries associated with the current billing cycle under the contracts. The Registrants have not provided any significant form of financial support associated with these long-term contracts. There is no significant potential exposure to loss as a result of DTE Energy's variable interests through these long-term purchase and sale contracts. In addition, there is no significant potential exposure to loss as a result of DTE Electric's variable interests through these long-term purchase contracts.

The maximum risk exposure for consolidated VIEs is reflected on the Registrants' Consolidated Statements of Financial Position and, for DTE Energy, in Note 11 to the Consolidated Financial Statements, "Commitments and Contingencies," related to the REF guarantees and indemnities. For non-consolidated VIEs, the maximum risk exposure of the Registrants is generally limited to their investment, notes receivable, future funding commitments, and amounts which DTE Energy has guaranteed. See Note 11 to the Consolidated Financial Statements, "Commitments and Contingencies," for further discussion of the NEXUS guarantee arrangements.

Changes in Accumulated Other Comprehensive Income (Loss)

For the three and nine months ended September 30, 2018 and 2017, reclassifications out of Accumulated other comprehensive income (loss) for the Registrants were not material. Changes in Accumulated other comprehensive income (loss) are presented in DTE Energy's Consolidated Statements of Changes in Equity and DTE Electric's Consolidated Statements of Changes in Shareholder's Equity. For further discussion regarding changes in Accumulated other comprehensive income (loss), see Note 3 to the Consolidated Financial Statements, "New Accounting Pronouncements."

Cash, Cash Equivalents, and Restricted Cash

Cash and cash equivalents include cash on hand, cash in banks, and temporary investments purchased with remaining maturities of three months or less. Restricted cash consists of funds held to satisfy requirements of certain debt and DTE Energy partnership operating agreements. Restricted cash designated for interest and principal payments within one year is classified as a Current Asset.

Recently Adopted and Recently Issued Pronouncements

Recently Adopted Pronouncements

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), as amended. The objectives of this ASU are to improve upon revenue recognition requirements by providing a single comprehensive model to determine the measurement of revenue and timing of recognition. The core principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. This ASU also required expanded qualitative and quantitative disclosures regarding the nature, amount, timing, and uncertainty of revenues and cash flows arising from contracts with customers. The standard is to be applied retrospectively. The Registrants adopted the standard effective January 1, 2018, using the modified retrospective approach. Under the modified retrospective approach, the information for periods prior to the adoption date has not been restated and continues to be reported under the accounting standards in effect for those periods. As permitted under the standard, the Registrants have elected to apply the guidance only to those contracts that were not completed at January 1, 2018, and have elected not to restate the impacts of any contract modifications made prior to the earliest period presented.

The adoption of the ASU did not have a significant impact on the Registrants' financial position or results of operations, but required additional disclosures for revenue. See Note 4 to the Consolidated Financial Statements, "Revenue."

In March 2017, the FASB issued ASU No. 2017-07, Compensation — Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost. The amendments in this update required that an employer report the service cost component in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside of income from operations. The amendments in this update also allow only the service cost component to be eligible for capitalization when applicable. The Registrants adopted the standard effective January 1, 2018. The standard has been applied retrospectively for the presentation of the service cost component and the other components of net periodic pension cost and net periodic postretirement benefit cost in the income statement and prospectively for the capitalization of the service cost component of net periodic pension cost and net periodic postretirement benefit in assets. As permitted by the standard, the Registrants have used benefit cost amounts disclosed for prior periods as the basis for retrospective application in the income statement. As a result of regulatory mechanisms, the impact to the Consolidated Financial Statements was not material for the three and nine months ended September 30, 2018.

In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments — Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities, as amended. The new guidance is intended to improve the recognition and measurement of financial instruments. The guidance primarily impacts accounting for equity investments in unconsolidated entities (other than those accounted for using the equity method of accounting) and financial liabilities under the fair value option. The guidance requires equity investments to be generally measured at fair value, with subsequent changes in fair value recognized in net income. The guidance requires entities to make a cumulative-effect adjustment to the Statements of Financial Position as of the beginning of the first reporting period in which the guidance is effective. The Registrants adopted the standard effective January 1, 2018. Upon adoption, DTE Energy and DTE Electric recorded a cumulative-effect adjustment to reclassify $5 million and $3 million of unrealized gains from Accumulated other comprehensive income (loss) to Retained earnings, respectively.

In March 2018, the FASB issued ASU No. 2018-05, Income Taxes (Topic 740): Amendments to SEC paragraphs pursuant to SEC Staff Accounting Bulletin No. 118. The Amendments in this update add various SEC paragraphs pursuant to the issuance of SEC Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cuts and Jobs Act (SAB 118). SAB 118 directs taxpayers to consider the implications of the TCJA as provisional when it does not have the necessary information available, prepared, or analyzed in reasonable detail to complete its accounting for the change in the tax law. As described in Note 10 to the Consolidated Financial Statements, "Income Taxes," within the combined DTE Energy and DTE Electric 2017 Annual Report on Form 10-K and in accordance with SAB 118, the Registrants recorded amounts that were considered provisional. During the nine months ended September 30, 2018, DTE Energy and DTE Electric recorded true-up adjustments to the remeasurement of deferred taxes of $21 million and $7 million, respectively. The impact of the true-up adjustments was an increase in Income Tax Expense, of which $16 million was attributable to the regulated utilities and offset to Regulatory liabilities. The true-up adjustments were a result of further analysis for items subject to further consideration at December 31, 2017, under SAB 118 and primarily related to timing differences not recoverable from DTE Electric and DTE Gas customers. Additionally, during the three and nine months ended September 30, 2018, DTE Energy recorded a valuation allowance of $20 million against AMT credits that are expected to be subject to sequestration when refunded in accordance with TCJA. This adjustment increased Income Tax Expense and reduced the deferred tax asset related to AMT credits determined to be unrealizable. The valuation allowance adjustment was the result of further analysis for items subject to further consideration at December 31, 2017 under SAB 118. The Registrants will continue to analyze the amounts throughout 2018, which may result in additional changes.

Recently Issued Pronouncements

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842), as amended. This guidance requires a lessee to account for leases as finance or operating leases, and disclose key information about leasing arrangements. Both types of leases will result in the lessee recognizing a right-of-use asset and a corresponding lease liability on its balance sheet, with differing methodology for income statement recognition, depending on the lease classification. The Registrants will adopt the standard on January 1, 2019. The standard allows lessees and lessors to apply either, 1) a modified retrospective approach for leases existing or entered into after the beginning of the earliest comparative period in the Consolidated Financial Statements, or 2) a prospective transition approach for leases existing as of January 1, 2019 with a cumulative effect adjustment to be recorded to retained earnings. The Registrants plan to apply the standard on a prospective basis. The Registrants expect to elect the package of practical expedients allowing entities to not reassess whether an agreement is a lease, to carryforward the existing lease classification, and to not reassess initial direct costs associated with existing leases. The Registrants also plan to elect to exclude leases from the balance sheet that are for a period of one year or less, as well as, the practical expedient allowing entities to not evaluate land easements under the new guidance at adoption if they were not previously accounted for as leases.

A third-party software tool is being implemented that will assist with the initial adoption and ongoing compliance of the standard. Preliminary system configuration has been completed and testing is in progress. The Registrants are continuing procedures to ensure all leases are captured, as well as, evaluating and implementing, new business processes, internal controls, and accounting policies. In addition, the Registrants are monitoring utility industry implementation issues for purchase power agreements, pipeline laterals, and other industry specific arrangements. While the Registrants expect an increase in assets and liabilities, as well as additional disclosures, they are still assessing the impact of this ASU on their Consolidated Financial Statements.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The amendments in this update replace the incurred loss impairment methodology in current generally accepted accounting principles with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Entities will apply the new guidance as a cumulative-effect adjustment to retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The ASU is effective for the Registrants beginning after December 15, 2019, and interim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated Financial Statements.

In February 2018, the FASB issued ASU No. 2018-02, Income Statement — Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The amendments in this update allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the TCJA. The amendments in this update also require entities to disclose their accounting policy for releasing income tax effects from accumulated other comprehensive income. The ASU is effective for the Registrants for fiscal years beginning after December 15, 2018, and interim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated Financial Statements.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurements (Topic 820): Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement. The amendments in this update modify the disclosure requirements on fair value measurements in Topic 820. The ASU is effective for the Registrants for fiscal years beginning after December 15, 2019, and interim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated Financial Statements.

In August 2018, the FASB issued ASU No. 2018-14, Compensation — Retirement Benefits — Defined Benefit Plans (Subtopic 715-20): Disclosure Framework — Changes to the Disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The amendments in this update modify the disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. The ASU is effective for the Registrants for fiscal years ending after December 15, 2020. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated Financial Statements.

In August 2018, the FASB issued ASU No. 2018-15, Intangibles — Goodwill and Other — Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. The amendments in this update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software (and hosting arrangements that include an internal use software license). The ASU is effective for the Registrants for fiscal years beginning after December 15, 2019, and interim periods therein. Early adoption is permitted. The Registrants are currently assessing the impact of this standard on their Consolidated Financial Statements.

Revenue Recognition

Upon the adoption of Topic 606, revenue is measured based upon the consideration specified in a contract with a customer at the time when performance obligations are satisfied. Under Topic 606, a performance obligation is a promise in a contract to transfer a distinct good or service or a series of distinct goods or services to the customer. The Registrants recognize revenue when performance obligations are satisfied by transferring control over a product or service to a customer. The Registrants have determined control to be transferred when the product is delivered or the service is provided to the customer. For the three and nine months ended September 30, 2018, recognition of revenue for the Registrants subsequent to the adoption of Topic 606 is substantially similar in amount and approach to that prior to adoption.

Rates for DTE Electric and DTE Gas include provisions to adjust billings for fluctuations in fuel and purchased power costs, cost of natural gas, and certain other costs. Revenues are adjusted for differences between actual costs subject to reconciliation and the amounts billed in current rates. Under or over recovered revenues related to these cost recovery mechanisms are included in Regulatory assets or liabilities on the Registrants' Consolidated Statements of Financial Position and are recovered or returned to customers through adjustments to the billing factors.

Fair Value Measurement

Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date in a principal or most advantageous market. Fair value is a market-based measurement that is determined based on inputs, which refer broadly to assumptions that market participants use in pricing assets or liabilities. These inputs can be readily observable, market corroborated, or generally unobservable inputs. The Registrants make certain assumptions they believe that market participants would use in pricing assets or liabilities, including assumptions about risk, and the risks inherent in the inputs to valuation techniques. Credit risk of the Registrants and their counterparties is incorporated in the valuation of assets and liabilities through the use of credit reserves, the impact of which was immaterial at September 30, 2018 and December 31, 2017. The Registrants believe they use valuation techniques that maximize the use of observable market-based inputs and minimize the use of unobservable inputs.

A fair value hierarchy has been established that prioritizes the inputs to valuation techniques used to measure fair value in three broad levels. The fair value hierarchy gives the highest priority to quoted prices (unadjusted) in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3). In some cases, the inputs used to measure fair value might fall in different levels of the fair value hierarchy. All assets and liabilities are required to be classified in their entirety based on the lowest level of input that is significant to the fair value measurement in its entirety. Assessing the significance of a particular input may require judgment considering factors specific to the asset or liability, and may affect the valuation of the asset or liability and its placement within the fair value hierarchy. The Registrants classify fair value balances based on the fair value hierarchy defined as follows:


•	Level 1 — Consists of unadjusted quoted prices in active markets for identical assets or liabilities that the Registrants have the ability to access as of the reporting date.


•	Level 2 — Consists of inputs other than quoted prices included within Level 1 that are directly observable for the asset or liability or indirectly observable through corroboration with observable market data.


•	Level 3 — Consists of unobservable inputs for assets or liabilities whose fair value is estimated based on internally developed models or methodologies using inputs that are generally less readily observable and supported by little, if any, market activity at the measurement date. Unobservable inputs are developed based on the best available information and subject to cost-benefit constraints.

Nuclear Decommissioning Trusts and Other Investments

The nuclear decommissioning trusts and other investments hold debt and equity securities directly and indirectly through institutional mutual funds and commingled funds. Other assets such as private market investments are used to enhance long-term returns while improving portfolio diversification. All pricing for private market investments in this category are classified as NAV assets. Exchange-traded debt and equity securities held directly are valued using quoted market prices in actively traded markets. Non-exchange-traded fixed income securities are valued based upon quotations available from brokers or pricing services. The institutional mutual funds hold exchange-traded equity or debt securities (exchange and non-exchange traded) and are valued based on publicly available NAVs. A primary price source is identified by asset type, class, or issue for each security. The trustee monitors prices supplied by pricing services and may use a supplemental price source or change the primary price source of a given security if the trustee determines that another price source is considered preferable. The Registrants have obtained an understanding of how these prices are derived, including the nature and observability of the inputs used in deriving such prices. Additionally, the Registrants selectively corroborate the fair value of securities by comparison of market-based price sources. Investment policies and procedures are determined by DTE Energy's Trust Investments Department which reports to DTE Energy's Vice President and Treasurer.

Derivative Assets and Liabilities

Derivative assets and liabilities are comprised of physical and financial derivative contracts, including futures, forwards, options, and swaps that are both exchange-traded and over-the-counter traded contracts. Various inputs are used to value derivatives depending on the type of contract and availability of market data. Exchange-traded derivative contracts are valued using quoted prices in active markets. The Registrants consider the following criteria in determining whether a market is considered active: frequency in which pricing information is updated, variability in pricing between sources or over time, and the availability of public information. Other derivative contracts are valued based upon a variety of inputs including commodity market prices, broker quotes, interest rates, credit ratings, default rates, market-based seasonality, and basis differential factors. The Registrants monitor the prices that are supplied by brokers and pricing services and may use a supplemental price source or change the primary price source of an index if prices become unavailable or another price source is determined to be more representative of fair value. The Registrants have obtained an understanding of how these prices are derived. Additionally, the Registrants selectively corroborate the fair value of their transactions by comparison of market-based price sources. Mathematical valuation models are used for derivatives for which external market data is not readily observable, such as contracts which extend beyond the actively traded reporting period. The Registrants have established a Risk Management Committee whose responsibilities include directly or indirectly ensuring all valuation methods are applied in accordance with predefined policies. The development and maintenance of the Registrants' forward price curves has been assigned to DTE Energy's Risk Management Department, which is separate and distinct from the trading functions within DTE Energy.

Fair Value Transfer

Derivatives are transferred between levels primarily due to changes in the source data used to construct price curves as a result of changes in market liquidity. Transfers in and transfers out are reflected as if they had occurred at the beginning of the period.

Derivatives

The Registrants recognize all derivatives at their fair value as Derivative assets or liabilities on their respective Consolidated Statements of Financial Position unless they qualify for certain scope exceptions, including the normal purchases and normal sales exception. Further, derivatives that qualify and are designated for hedge accounting are classified as either hedges of a forecasted transaction or the variability of cash flows to be received or paid related to a recognized asset or liability (cash flow hedge); or as hedges of the fair value of a recognized asset or liability or of an unrecognized firm commitment (fair value hedge). For cash flow hedges, the portion of the derivative gain or loss that is effective in offsetting the change in the value of the underlying exposure is deferred in Accumulated other comprehensive income (loss) and later reclassified into earnings when the underlying transaction occurs. Gains or losses from the ineffective portion of cash flow hedges are recognized in earnings immediately. For fair value hedges, changes in fair values for the derivative and hedged item are recognized in earnings each period. For derivatives that do not qualify or are not designated for hedge accounting, changes in fair value are recognized in earnings each period.

The Registrants’ primary market risk exposure is associated with commodity prices, credit, and interest rates. The Registrants have risk management policies to monitor and manage market risks. The Registrants use derivative instruments to manage some of the exposure. DTE Energy uses derivative instruments for trading purposes in its Energy Trading segment. Contracts classified as derivative instruments include electricity, natural gas, oil, certain coal forwards, futures, options, swaps, and foreign currency exchange contracts. Items not classified as derivatives include natural gas inventory, pipeline transportation contracts, renewable energy credits, and natural gas storage assets.

DTE Electric — DTE Electric generates, purchases, distributes, and sells electricity. DTE Electric uses forward contracts to manage changes in the price of electricity and fuel. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. Other derivative contracts are MTM and recoverable through the PSCR mechanism when settled. This results in the deferral of unrealized gains and losses as Regulatory assets or liabilities until realized.

DTE Gas — DTE Gas purchases, stores, transports, distributes, and sells natural gas, and sells storage and transportation capacity. DTE Gas has fixed-priced contracts for portions of its expected natural gas supply requirements through March 2021. Substantially all of these contracts meet the normal purchases and normal sales exception and are therefore accounted for under the accrual method. DTE Gas may also sell forward transportation and storage capacity contracts. Forward transportation and storage contracts are generally not derivatives and are therefore accounted for under the accrual method.

Gas Storage and Pipelines — This segment is primarily engaged in services related to the gathering, transportation, and storage of natural gas. Primarily fixed-priced contracts are used in the marketing and management of transportation and storage services. Generally, these contracts are not derivatives and are therefore accounted for under the accrual method.

Power and Industrial Projects — This segment manages and operates energy and pulverized coal projects, a coke battery, reduced emissions fuel projects, landfill gas recovery, and power generation assets. Primarily fixed-price contracts are used in the marketing and management of the segment assets. These contracts are generally not derivatives and are therefore accounted for under the accrual method.

Energy Trading — Commodity Price Risk — Energy Trading markets and trades electricity, natural gas physical products, and energy financial instruments, and provides energy and asset management services utilizing energy commodity derivative instruments. Forwards, futures, options, and swap agreements are used to manage exposure to the risk of market price and volume fluctuations in its operations. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.

Energy Trading — Foreign Currency Exchange Risk — Energy Trading has foreign currency exchange forward contracts to economically hedge fixed Canadian dollar commitments existing under natural gas and power purchase and sale contracts and natural gas transportation contracts. Energy Trading enters into these contracts to mitigate price volatility with respect to fluctuations of the Canadian dollar relative to the U.S. dollar. These derivatives are accounted for by recording changes in fair value to earnings unless hedge accounting criteria are met.

Corporate and Other — Interest Rate Risk — DTE Energy may use interest rate swaps, treasury locks, and other derivatives to hedge the risk associated with interest rate market volatility.

Credit Risk — DTE Energy maintains credit policies that significantly minimize overall credit risk. These policies include an evaluation of potential customers’ and counterparties’ financial condition, including the viability of underlying productive assets, credit rating, collateral requirements, or other credit enhancements such as letters of credit or guarantees. DTE Energy generally uses standardized agreements that allow the netting of positive and negative transactions associated with a single counterparty. DTE Energy maintains a provision for credit losses based on factors surrounding the credit risk of its customers, historical trends, and other information. Based on DTE Energy's credit policies and its September 30, 2018 provision for credit losses, DTE Energy’s exposure to counterparty nonperformance is not expected to have a material adverse effect on DTE Energy's Consolidated Financial Statements.

Derivatives, Offsetting Fair Value Amounts

Certain of DTE Energy's derivative positions are subject to netting arrangements which provide for offsetting of asset and liability positions as well as related cash collateral. Such netting arrangements generally do not have restrictions. Under such netting arrangements, DTE Energy offsets the fair value of derivative instruments with cash collateral received or paid for those contracts executed with the same counterparty, which reduces DTE Energy's Total Assets and Liabilities. Cash collateral is allocated between the fair value of derivative instruments and customer accounts receivable and payable with the same counterparty on a pro-rata basis to the extent there is exposure. Any cash collateral remaining, after the exposure is netted to zero, is reflected in Accounts receivable and Accounts payable as collateral paid or received, respectively.

DTE Energy also provides and receives collateral in the form of letters of credit which can be offset against net Derivative assets and liabilities as well as Accounts receivable and payable. DTE Energy had issued letters of credit of $4 million outstanding at September 30, 2018 and December 31, 2017, which could be used to offset net Derivative liabilities. Letters of credit received from third parties which could be used to offset net Derivative assets were $6 million and $4 million at September 30, 2018 and December 31, 2017, respectively. Such balances of letters of credit are excluded from the tables below and are not netted with the recognized assets and liabilities in DTE Energy's Consolidated Statements of Financial Position.

For contracts with certain clearing agents, the fair value of derivative instruments is netted against realized positions with the net balance reflected as either 1) a Derivative asset or liability or 2) an Account receivable or payable. Other than certain clearing agents, Accounts receivable and Accounts payable that are subject to netting arrangements have not been offset against the fair value of Derivative assets and liabilities.

Derivatives, Methods of Accounting, Derivatives Not Designated or Qualifying as Hedges

Revenues and energy costs related to trading contracts are presented on a net basis in DTE Energy's Consolidated Statements of Operations. Commodity derivatives used for trading purposes, and financial non-trading commodity derivatives, are accounted for using the MTM method with unrealized and realized gains and losses recorded in Operating Revenues — Non-utility operations. Non-trading physical commodity sale and purchase derivative contracts are generally accounted for using the MTM method with unrealized and realized gains and losses for sales recorded in Operating Revenues — Non-utility operations and purchases recorded in Fuel, purchased power, and gas — non-utility.

Income Tax

The federal income tax provisions or benefits of DTE Energy’s subsidiaries are determined on an individual company basis and recognize the tax benefit of tax credits and net operating losses, if applicable. The state and local income tax provisions of the utility subsidiaries are determined on an individual company basis and recognize the tax benefit of various tax credits and net operating losses, if applicable. The subsidiaries record federal, state, and local income taxes payable to or receivable from DTE Energy based on the federal, state, and local tax provisions of each company.