Significant Accounting Policies (Policies)	12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The Consolidated Financial Statements and Notes to Consolidated Financial Statements as of and for the periods presented subsequent to July 1, 2021, the date of the Separation, reflect the consolidated financial position, results of operations and cash flows for DT Midstream as an independent company. Prior to the Separation, we operated as a consolidated entity of DTE Energy and not as a standalone company. For the periods prior to the Separation, the Consolidated Financial Statements and Notes to Consolidated Financial Statements were prepared on a carve-out basis using the consolidated financial statements and accounting records of DTE Energy. The carve-out basis financial statements represent our historical financial position, results of operations, and cash flows as they were historically managed in accordance with GAAP and reflect significant assumptions and allocations. The carve-out financial statements may not include all expenses that would have been incurred had we existed as a standalone entity. GAAP requires 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 our estimates. We believe the assumptions underlying these financial statements are reasonable.
Principles of Consolidation	Principles of Consolidation We consolidate all majority-owned subsidiaries and investments in entities in which we have a controlling influence. Non-controlled investments are accounted for using the equity method of accounting when we are able to significantly influence the operating policies of the investee. When we do not influence the operating policies of an investee, the equity investment is measured at fair value, if readily determinable, or if not readily determinable, at cost less impairment, if applicable. We eliminate all intercompany balances and transactions. We evaluate whether an entity is a VIE whenever reconsideration events occur. We consolidate VIEs for which we are the primary beneficiary. If we are 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, we consider 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. We perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed. We own an 85% interest in the Stonewall VIE and are the primary beneficiary, therefore Stonewall is consolidated. We own a 50% interest in the South Romeo VIE and are the primary beneficiary, therefore South Romeo is consolidated.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include cash in banks and highly liquid money market investments with remaining maturities of three months or less, when purchased. Cash equivalents are stated at cost, which approximates fair value.
Financing Receivables	Financing Receivables Financing receivables are primarily composed of trade accounts receivable and notes receivable, which are stated at net realizable value. We regularly monitor the credit quality of our financing receivables by reviewing counterparty credit quality indicators and monitoring for triggering events, such as a credit rating downgrade or bankruptcy. We have three internal grades of credit quality, with internal grade 1 as the lowest risk and internal grade 3 as the highest risk. The related credit quality indicators and risk ratings utilized to develop the internal grades have been updated through December 31, 2023. As of December 31, 2023, the Notes receivable — related party of $4 million, which originated prior to 2021, was classified as internal grade 1. There are no notes receivable on nonaccrual status and no past due financing receivables as of December 31, 2023. Notes receivable are typically considered delinquent (past due) when payment is not received for periods ranging from 60 to 120 days. We cease accruing interest income (nonaccrual status) and may either write off or establish an allowance for expected credit loss for the note receivable when it is expected that all contractual principal or interest amounts due will not be collected. In determining an allowance for expected credit losses for or the write off of notes receivable, we consider the historical payment experience and other factors that are expected to have a specific impact on collection, including existing and future economic conditions. Cash receipts for notes receivable on nonaccrual status that do not bring the account contractually current are first applied to contractually owed past due interest, with any remainder applied to principal. Recognition of interest income is generally resumed when the note receivable becomes contractually current. We had an investment in certain assets in the Utica Shale region which was accounted for as a note receivable — third party. In the second quarter 2021, we assessed the note receivable for expected loss and recorded a $19 million loss on the note receivable to Asset (gains) losses and impairments, net on the Consolidated Statement of Operations. Additionally, we ceased accruing interest on the note receivable balance and reclassified the note to an Internal grade 3 receivable. Subsequently, as cash payments were received, a portion was recognized as interest income. A third party purchased our investment in certain assets in the Utica Shale region based on significantly improved commodity pricing during the second quarter 2022 for proceeds of $22 million. This resulted in a gain of $17 million recorded in Asset (gains) losses and impairments, net on the Consolidated Statement of Operations. We maintain no continuing involvement with the note receivable. For trade accounts receivable, the customer allowance for expected credit loss is calculated based on specific review of future collections based on receivable balances generally in excess of 30 days. Existing and future economic conditions, historical loss rates, customer trends and other relevant factors that may affect our ability to collect are also considered. Receivables are written off on a specific identification basis and determined based on the particular circumstances of the associated receivable.
Property, Plant, and Equipment	Property, Plant, and Equipment Property is stated at cost and includes construction-related labor, materials, and overhead. Expenditures for maintenance and repairs are charged to expense when incurred. Property, plant and equipment is depreciated over its estimated useful life using the straight-line method.
Intangible Assets and Long-Lived Assets	Intangible Assets Intangible assets with finite useful lives are amortized on a straight-line basis over the periods benefited. See Note 6, "Property, Plant, and Equipment and Intangible Assets" to the Consolidated Financial Statements. Long-Lived Assets Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected undiscounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.
Operations and Maintenance	Operation and Maintenance Operation and maintenance is primarily comprised of costs for labor and employee benefits, outside services, materials, compression, purchased natural gas, operating lease costs, office costs, and other operating and maintenance costs. For the year ended December 31, 2021, general corporate expense allocations from DTE Energy of $32 million, including $20 million of Separation-related transaction costs for legal, accounting, auditing and other professional services DTE Energy incurred for the benefit of DT Midstream, were also included in operation and maintenance. Effective July 1, 2021, with the completion of the Separation, we no longer received corporate allocations from DTE Energy.
Depreciation and Amortization	Depreciation and Amortization Depreciation and amortization is related to Property, plant and equipment and Customer relationships and other intangible assets, net, used in our transportation, storage and gathering businesses.
Recently Issued Pronouncements	Recently Issued Pronouncements In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280) - Improvements to Reportable Segment Disclosures. The amendments improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and interim disclosure requirements. The amendments are effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on our Consolidated Financial Statements. In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740) - Improvements to Income Tax Disclosures. The amendments improve transparency of income tax disclosure requirements, primarily through enhanced disclosures of rate reconciliation and income taxes paid. The amendments are effective for annual periods beginning after December 15, 2024. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on our Consolidated Financial Statements.
Accounting for Income Taxes	Significant Accounting Policy – Accounting for Income Taxes We record the effect of income taxes in accordance with GAAP, which provides for the use of an asset and liability approach. Deferred income tax assets and liabilities are recognized for temporary differences between the basis of assets and liabilities for financial reporting and tax purposes and measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities as a result of changes in the enacted tax rates is recognized in earnings in the period of enactment. Our recognition of deferred tax assets is based upon a more-likely-than-not criterion. We routinely assess realizability based on objectively-weighted, available positive and negative evidence. We account for uncertainties in income taxes using a benefit recognition model with a two-step approach: a more-likely-than-not recognition criterion, and a measurement attribute that measures the position as the largest amount of tax benefit that is greater than a 50% likelihood of being realized upon ultimate settlement. If the benefit does not meet the more likely than not criteria for being sustained on its technical merits, no benefit will be recorded. Uncertain tax positions that relate only to timing of when an item is included on a tax return are considered to have met the recognition threshold.
Revenue	Significant Accounting Policy – Revenue Pipeline revenues consist of services related to the gathering, transportation and/or storage of natural gas. Gathering revenues consist of services related to the gathering, processing, and/or treating of natural gas. Revenue is measured based upon the pricing or consideration for such services specified in the contract with a customer. Consideration may consist of both fixed components including fixed demand charges and fixed deficiency fee rates for MVCs, and variable components including fixed rates for the actual volumes flowed under interruptible services and other associated fees. Our contracts with customers generally contain a single performance obligation, which is a promise to deliver either a distinct service or a series of distinct services to the customer. When multiple performance obligations exist, the contract consideration is allocated between the performance obligations based on the relative standalone selling price, which is determined by prices charged to customers or the adjusted market assessment approach. The adjusted market assessment approach involves evaluating the market in which we sell services and estimating the price that a customer in that market would be willing to pay. Revenue is recognized when performance obligations are satisfied by delivering a service to a customer, which occurs when the service is provided to the customer. When a customer simultaneously receives and consumes the service provided, revenue is recognized over time. Alternatively, if it is determined that the criteria for recognition of revenue over time is not met, the revenue is considered to be recognized at a point in time. Our revenues, including estimated unbilled amounts, are generally recognized over time as actual services are provided, or ratably over time when providing a stand-ready service. Unbilled amounts are generally determined using preliminary meter data volumes and contracted pricing, and typically result in minor adjustments. Generally, uncertainties in the variable consideration components are resolved and revenue amounts are known at the time of recognition. We have determined that the above methods represent a faithful depiction of delivering a service to the customer. Revenues are typically billed and consideration received monthly, however, certain deficiency fees related to MVCs are billed quarterly or annually.
Lessee	Lessee Our leases are primarily comprised of equipment and buildings with terms ranging from approximately 3 to 11 years. A lease exists when we have the right to control the use of identified property, plant or equipment, as conveyed through a contract, for a certain time period and consideration paid. The right to control is deemed to occur when we have the right to obtain substantially all of the economic benefits of the identified assets and the right to direct the use of such assets. Lease liabilities are calculated utilizing a discount rate to determine the present values of lease payments. GAAP requires the use of the rate implicit in the lease if it is readily determinable. When the rate implicit in the lease is not readily determinable, the incremental borrowing rate is used. The incremental borrowing rate is based upon the rate of interest that would have been paid on a collateralized basis over similar contract terms to that of the leases. The incremental borrowing rates have been determined utilizing an implied secured borrowing rate based upon an unsecured rate for a similar time period of remaining lease terms, which is then adjusted for the estimated impact of collateral. We have leases with non-index-based escalation clauses for fixed dollar or percentage increases over the contract term. We have certain leases which contain purchase options. Based upon the nature of the leased property and terms of the purchase options, we have determined it is not reasonably certain that such purchase options will be exercised. Thus, the impact of the purchase options has not been included in the determination of right-of-use assets and lease liabilities for the subject leases. We have certain leases which contain renewal options. Where the renewal options were deemed reasonably certain to occur, the impacts of such options were included in the determination of the right-of-use assets and lease liabilities for the subject leases. We have agreements with lease and non-lease components, which are generally accounted for separately. Consideration in a lease is allocated between lease and non-lease components based upon the estimated relative standalone prices.
Lessor	Lessor We lease assets under an operating lease for a pipeline which commenced in December 2018. The lease is comprised of fixed payments with a remaining term of 15 years. The operating lease does not have renewal provisions or options to purchase the assets at the end of the lease and does not have termination for convenience provisions. The lease term extends to the end of the estimated economic life of the leased assets, thereby resulting in no residual value. A lease exists when we have provided other parties with the right to control the use of identified property, plant or equipment, as conveyed through a contract, for a certain time period and consideration received. The right to control is deemed to occur when we have provided other parties with the right to obtain substantially all of the economic benefits of the identified assets and the right to direct the use of such assets.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2023

The Consolidated Financial Statements and Notes to Consolidated Financial Statements as of and for the periods presented subsequent to July 1, 2021, the date of the Separation, reflect the consolidated financial position, results of operations and cash flows for DT Midstream as an independent company. Prior to the Separation, we operated as a consolidated entity of DTE Energy and not as a standalone company. For the periods prior to the Separation, the Consolidated Financial Statements and Notes to Consolidated Financial Statements were prepared on a carve-out basis using the consolidated financial statements and accounting records of DTE Energy. The carve-out basis financial statements represent our historical financial position, results of operations, and cash flows as they were historically managed in accordance with GAAP and reflect significant assumptions and allocations. The carve-out financial statements may not include all expenses that would have been incurred had we existed as a standalone entity.

GAAP requires 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 our estimates. We believe the assumptions underlying these financial statements are reasonable.

Principles of Consolidation

We consolidate all majority-owned subsidiaries and investments in entities in which we have a controlling influence. Non-controlled investments are accounted for using the equity method of accounting when we are able to significantly influence the operating policies of the investee. When we do not influence the operating policies of an investee, the equity investment is measured at fair value, if readily determinable, or if not readily determinable, at cost less impairment, if applicable. We eliminate all intercompany balances and transactions.

We evaluate whether an entity is a VIE whenever reconsideration events occur. We consolidate VIEs for which we are the primary beneficiary. If we are 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, we consider 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. We perform ongoing reassessments of all VIEs to determine if the primary beneficiary status has changed.

We own an 85% interest in the Stonewall VIE and are the primary beneficiary, therefore Stonewall is consolidated. We own a 50% interest in the South Romeo VIE and are the primary beneficiary, therefore South Romeo is consolidated.

Cash and Cash Equivalents

Cash and cash equivalents include cash in banks and highly liquid money market investments with remaining maturities of three months or less, when purchased. Cash equivalents are stated at cost, which approximates fair value.

Financing Receivables

Financing receivables are primarily composed of trade accounts receivable and notes receivable, which are stated at net realizable value.

We regularly monitor the credit quality of our financing receivables by reviewing counterparty credit quality indicators and monitoring for triggering events, such as a credit rating downgrade or bankruptcy. We have three internal grades of credit quality, with internal grade 1 as the lowest risk and internal grade 3 as the highest risk. The related credit quality indicators and risk ratings utilized to develop the internal grades have been updated through December 31, 2023. As of December 31, 2023, the Notes receivable — related party of $4 million, which originated prior to 2021, was classified as internal grade 1. There are no notes receivable on nonaccrual status and no past due financing receivables as of December 31, 2023.

Notes receivable are typically considered delinquent (past due) when payment is not received for periods ranging from 60 to 120 days. We cease accruing interest income (nonaccrual status) and may either write off or establish an allowance for expected credit loss for the note receivable when it is expected that all contractual principal or interest amounts due will not be collected. In determining an allowance for expected credit losses for or the write off of notes receivable, we consider the historical payment experience and other factors that are expected to have a specific impact on collection, including existing and future economic conditions. Cash receipts for notes receivable on nonaccrual status that do not bring the account contractually current are first applied to contractually owed past due interest, with any remainder applied to principal. Recognition of interest income is generally resumed when the note receivable becomes contractually current.

We had an investment in certain assets in the Utica Shale region which was accounted for as a note receivable — third party. In the second quarter 2021, we assessed the note receivable for expected loss and recorded a $19 million loss on the note receivable to Asset (gains) losses and impairments, net on the Consolidated Statement of Operations. Additionally, we ceased accruing interest on the note receivable balance and reclassified the note to an Internal grade 3 receivable. Subsequently, as cash payments were received, a portion was recognized as interest income. A third party purchased our investment in certain assets in the Utica Shale region based on significantly improved commodity pricing during the second quarter 2022 for proceeds of $22 million. This resulted in a gain of $17 million recorded in Asset (gains) losses and impairments, net on the Consolidated Statement of Operations. We maintain no continuing involvement with the note receivable.

For trade accounts receivable, the customer allowance for expected credit loss is calculated based on specific review of future collections based on receivable balances generally in excess of 30 days. Existing and future economic conditions, historical loss rates, customer trends and other relevant factors that may affect our ability to collect are also considered. Receivables are written off on a specific identification basis and determined based on the particular circumstances of the associated receivable.

Property, Plant, and Equipment

Property is stated at cost and includes construction-related labor, materials, and overhead. Expenditures for maintenance and repairs are charged to expense when incurred. Property, plant and equipment is depreciated over its estimated useful life using the straight-line method.

Intangible Assets and Long-Lived Assets

Intangible Assets

Intangible assets with finite useful lives are amortized on a straight-line basis over the periods benefited. See Note 6, "Property, Plant, and Equipment and Intangible Assets" to the Consolidated Financial Statements.

Long-Lived Assets

Long-lived assets are reviewed for impairment whenever events or changes in circumstances indicate the carrying amount of an asset may not be recoverable. If the carrying amount of the asset exceeds the expected undiscounted future cash flows generated by the asset, an impairment loss is recognized resulting in the asset being written down to its estimated fair value. Assets to be disposed of are reported at the lower of the carrying amount or fair value, less costs to sell.

Operations and Maintenance

Operation and Maintenance

Operation and maintenance is primarily comprised of costs for labor and employee benefits, outside services, materials, compression, purchased natural gas, operating lease costs, office costs, and other operating and maintenance costs. For the year ended December 31, 2021, general corporate expense allocations from DTE Energy of $32 million, including $20 million of Separation-related transaction costs for legal, accounting, auditing and other professional services DTE Energy incurred for the benefit of DT Midstream, were also included in operation and maintenance. Effective July 1, 2021, with the completion of the Separation, we no longer received corporate allocations from DTE Energy.

Depreciation and Amortization

Depreciation and amortization is related to Property, plant and equipment and Customer relationships and other intangible assets, net, used in our transportation, storage and gathering businesses.

Recently Issued Pronouncements

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280) - Improvements to Reportable Segment Disclosures. The amendments improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant segment expenses and interim disclosure requirements. The amendments are effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on our Consolidated Financial Statements.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740) - Improvements to Income Tax Disclosures. The amendments improve transparency of income tax disclosure requirements, primarily through enhanced disclosures of rate reconciliation and income taxes paid. The amendments are effective for annual periods beginning after December 15, 2024. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on our Consolidated Financial Statements.

Accounting for Income Taxes

Significant Accounting Policy – Accounting for Income Taxes

We record the effect of income taxes in accordance with GAAP, which provides for the use of an asset and liability approach. Deferred income tax assets and liabilities are recognized for temporary differences between the basis of assets and liabilities for financial reporting and tax purposes and measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities as a result of changes in the enacted tax rates is recognized in earnings in the period of enactment. Our recognition of deferred tax assets is based upon a more-likely-than-not criterion. We routinely assess realizability based on objectively-weighted, available positive and negative evidence.

We account for uncertainties in income taxes using a benefit recognition model with a two-step approach: a more-likely-than-not recognition criterion, and a measurement attribute that measures the position as the largest amount of tax benefit that is greater than a 50% likelihood of being realized upon ultimate settlement. If the benefit does not meet the more likely than not criteria for being sustained on its technical merits, no benefit will be recorded. Uncertain tax positions that relate only to timing of when an item is included on a tax return are considered to have met the recognition threshold.

Revenue

Significant Accounting Policy – Revenue

Pipeline revenues consist of services related to the gathering, transportation and/or storage of natural gas. Gathering revenues consist of services related to the gathering, processing, and/or treating of natural gas. Revenue is measured based upon the pricing or consideration for such services specified in the contract with a customer. Consideration may consist of both fixed components including fixed demand charges and fixed deficiency fee rates for MVCs, and variable components including fixed rates for the actual volumes flowed under interruptible services and other associated fees.

Our contracts with customers generally contain a single performance obligation, which is a promise to deliver either a distinct service or a series of distinct services to the customer. When multiple performance obligations exist, the contract consideration is allocated between the performance obligations based on the relative standalone selling price, which is determined by prices charged to customers or the adjusted market assessment approach. The adjusted market assessment approach involves evaluating the market in which we sell services and estimating the price that a customer in that market would be willing to pay.

Revenue is recognized when performance obligations are satisfied by delivering a service to a customer, which occurs when the service is provided to the customer. When a customer simultaneously receives and consumes the service provided, revenue is recognized over time. Alternatively, if it is determined that the criteria for recognition of revenue over time is not met, the revenue is considered to be recognized at a point in time. Our revenues, including estimated unbilled amounts, are generally recognized over time as actual services are provided, or ratably over time when providing a stand-ready service. Unbilled amounts are generally determined using preliminary meter data volumes and contracted pricing, and typically result in minor adjustments. Generally, uncertainties in the variable consideration components are resolved and revenue amounts are known at the time of recognition. We have determined that the above methods represent a faithful depiction of delivering a service to the customer. Revenues are typically billed and consideration received monthly, however, certain deficiency fees related to MVCs are billed quarterly or annually.

Lessee

Our leases are primarily comprised of equipment and buildings with terms ranging from approximately 3 to 11 years.

A lease exists when we have the right to control the use of identified property, plant or equipment, as conveyed through a contract, for a certain time period and consideration paid. The right to control is deemed to occur when we have the right to obtain substantially all of the economic benefits of the identified assets and the right to direct the use of such assets.

Lease liabilities are calculated utilizing a discount rate to determine the present values of lease payments. GAAP requires the use of the rate implicit in the lease if it is readily determinable. When the rate implicit in the lease is not readily determinable, the incremental borrowing rate is used. The incremental borrowing rate is based upon the rate of interest that would have been paid on a collateralized basis over similar contract terms to that of the leases. The incremental borrowing rates have been determined utilizing an implied secured borrowing rate based upon an unsecured rate for a similar time period of remaining lease terms, which is then adjusted for the estimated impact of collateral. We have leases with non-index-based escalation clauses for fixed dollar or percentage increases over the contract term.

We have certain leases which contain purchase options. Based upon the nature of the leased property and terms of the purchase options, we have determined it is not reasonably certain that such purchase options will be exercised. Thus, the impact of the purchase options has not been included in the determination of right-of-use assets and lease liabilities for the subject leases.

We have certain leases which contain renewal options. Where the renewal options were deemed reasonably certain to occur, the impacts of such options were included in the determination of the right-of-use assets and lease liabilities for the subject leases.

We have agreements with lease and non-lease components, which are generally accounted for separately. Consideration in a lease is allocated between lease and non-lease components based upon the estimated relative standalone prices.

Lessor

We lease assets under an operating lease for a pipeline which commenced in December 2018. The lease is comprised of fixed payments with a remaining term of 15 years. The operating lease does not have renewal provisions or options to purchase the assets at the end of the lease and does not have termination for convenience provisions. The lease term extends to the end of the estimated economic life of the leased assets, thereby resulting in no residual value.

A lease exists when we have provided other parties with the right to control the use of identified property, plant or equipment, as conveyed through a contract, for a certain time period and consideration received. The right to control is deemed to occur when we have provided other parties with the right to obtain substantially all of the economic benefits of the identified assets and the right to direct the use of such assets.