SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
Jun. 30, 2025
Accounting Policies [Abstract]
SIGNIFICANT ACCOUNTING POLICIES	SIGNIFICANT ACCOUNTING POLICIES 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 June 30, 2025. As of June 30, 2025, the notes receivable — related party of $4 million, which originated prior to 2021, were classified as internal grade 1. There are no notes receivable on nonaccrual status and no past due financing receivables as of June 30, 2025. 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. Uncollectible expense (recovery) was zero for each of the three and six months ended June 30, 2025 and 2024. Our collections on accounts receivable from customers are current, and no material rate of historical loss was noted, which resulted in no allowance for expected credit loss as of June 30, 2025 or December 31, 2024. Any balance would be shown as a deduction from the respective financing receivable's balance in the Consolidated Statements of Financial Position. 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. Property, Plant, and Equipment Property is stated at cost and includes construction-related labor, materials, overhead and capitalized interest. Property for FERC-regulated entities includes debt and equity AFUDC. Debt AFUDC represents capitalized interest. Equity AFUDC represents the capitalization of the estimated average cost of equity during FERC-regulated construction projects and is recorded as a credit to allowance for funds used during construction in our Consolidated Statements of Operations. 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. Regulated assets are accounted for under ASC 980, which in some cases requires that the cost of regulated property retired or sold, plus removal costs, less salvage, be charged to accumulated depreciation. For regulated assets, depreciation studies to assess the estimated useful lives of the asset are typically conducted as part of rate proceedings or tariff filings. Changes in economic lives, if applicable, are implemented prospectively as of the approved effective date. Our regulated properties are depreciated using the straight-line method based on composite depreciation rates applied to functional groups of properties with similar economic lives. 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. 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. Intangible Assets Intangible assets with finite useful lives are amortized on a straight-line basis over the periods benefited. Goodwill DT Midstream has goodwill resulting from business combinations. For each reporting unit with goodwill, we perform an impairment test annually or whenever events or circumstances indicate that the value of goodwill may be impaired. Lessor Accounting 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. All of our leases are classified as operating leases. Lease income is recognized on a straight-line, ratable basis over the fixed, non-cancelable term of the relevant contract. Lease income is reported in Operating revenues in our Consolidated Statements of Operations. Other Significant Accounting Policies There have been no changes to the summary of other significant accounting policies previously identified in the Company's Annual Report on Form 10-K for the year ended December 31, 2024.

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.

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 June 30, 2025. As of June 30, 2025, the notes receivable — related party of $4 million, which originated prior to 2021, were classified as internal grade 1. There are no notes receivable on nonaccrual status and no past due financing receivables as of June 30, 2025.

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. Uncollectible expense (recovery) was zero for each of the three and six months ended June 30, 2025 and 2024.

Our collections on accounts receivable from customers are current, and no material rate of historical loss was noted, which resulted in no allowance for expected credit loss as of June 30, 2025 or December 31, 2024. Any balance would be shown as a deduction from the respective financing receivable's balance in the Consolidated Statements of Financial Position.

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.

Property is stated at cost and includes construction-related labor, materials, overhead and capitalized interest. Property for FERC-regulated entities includes debt and equity AFUDC. Debt AFUDC represents capitalized interest. Equity AFUDC represents the capitalization of the estimated average cost of equity during FERC-regulated construction projects and is recorded as a credit to allowance for funds used during construction in our Consolidated Statements of Operations. 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.

Regulated assets are accounted for under ASC 980, which in some cases requires that the cost of regulated property retired or sold, plus removal costs, less salvage, be charged to accumulated depreciation. For regulated assets, depreciation studies to assess the estimated useful lives of the asset are typically conducted as part of rate proceedings or tariff filings. Changes in economic lives, if applicable, are implemented prospectively as of the approved effective date. Our regulated properties are depreciated using the straight-line method based on composite depreciation rates applied to functional groups of properties with similar economic lives.

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.

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.

DT Midstream has goodwill resulting from business combinations. For each reporting unit with goodwill, we perform an impairment test annually or whenever events or circumstances indicate that the value of goodwill may be impaired.

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. All of our leases are classified as operating leases. Lease income is recognized on a straight-line, ratable basis over the fixed, non-cancelable term of the relevant contract. Lease income is reported in Operating revenues in our Consolidated Statements of Operations.

There have been no changes to the summary of other significant accounting policies previously identified in the Company's Annual Report on Form 10-K for the year ended December 31, 2024.