PRESENTATION OF FINANCIAL INFORMATION	3 Months Ended
Mar. 31, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
PRESENTATION OF FINANCIAL INFORMATION	PRESENTATION OF FINANCIAL INFORMATION The accompanying unaudited consolidated financial statements, which represent the consolidated financial statements of Tri-State Generation and Transmission Association, Inc. (“Tri-State”) and its wholly owned and majority-owned subsidiaries, have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These unaudited consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in Tri-State's annual report on Form 10-K for the year ended December 31, 2025 filed with the SEC. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair presentation, have been included. Tri-State's consolidated financial position as of March 31, 2026, results of operations for the three months ended March 31, 2026 and 2025, and cash flows for the three months ended March 31, 2026 and 2025 are not necessarily indicative of the results that may be expected for an entire year or any other period. Basis of Consolidation Tri-State is a taxable wholesale electric power generation and transmission cooperative operating on a not-for-profit basis serving large portions of Colorado, Nebraska, New Mexico and Wyoming. Tri-State was incorporated under the laws of the State of Colorado in 1952. As of March 31, 2026, Tri-State had forty electric distribution member systems ("Utility Members") who are Class A - utility full requirements members to which it provides power pursuant to long-term wholesale electric service contracts. On April 1, 2026, La Plata Electric Association, Inc. ("LPEA") withdrew from membership in Tri-State. See Note 20 - Subsequent Events. Tri-State has three non-utility members (“Non-Utility Members”). Tri-State's Class A Utility Members and Non-Utility Members are collectively referred to as its “Members.” Tri-State provides wholesale power to its Utility Members at rates determined by its Board of Directors ("Board"), subject to Federal Energy Regulatory Commission (“FERC”) approval or acceptance. Rates are designed to recover all costs and provide margins to increase Utility Members' equity and to meet certain financial covenants, including a debt service ratio ("DSR") requirement and equity to capitalization ratio ("ECR") requirement. Tri-State complies with the Uniform System of Accounts as prescribed by FERC. In conformity with GAAP, the accounting policies and practices applied by Tri-State in the determination of rates are also employed for financial reporting purposes. The accompanying financial statements reflect the consolidated accounts of Tri-State, its wholly-owned and majority-owned subsidiaries, and certain variable interest entities for which Tri-State or its subsidiaries are the primary beneficiaries. See Note 18 – Variable Interest Entities. Tri-State's consolidated financial statements also include its undivided interests in jointly owned facilities. All significant intercompany balances and transactions have been eliminated in consolidation. Accounting Pronouncement - Not Yet Adopted In November 2024, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures. ASU 2024-03 requires a public business entity to disclose in a tabular format, on an annual and interim basis, purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses in the notes to the financial statements. Specified expenses, gains and losses that are already disclosed under existing GAAP are also required to be included in the disaggregated income statement expense line item disclosures and any remaining amounts need to be described qualitatively. Separate disclosures of total selling expenses and an entity's definition of those expenses are also required. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. Entities may apply the guidance prospectively or retrospectively. In January 2025, the FASB issued ASU 2025-01 to clarify the effective date of the ASU 2024-03 disaggregation disclosures requiring public companies to adopt the update beginning after December 15, 2026, and for interim periods within annual reporting periods beginning after December 15, 2027, while specifying that initial adoption should in in annual, not interim reporting. Tri-State is evaluating the adoption of these updates and its impact to its consolidated financial statements. In December 2025, the FASB issued ASU 2025-10, Government Grants (Topic 832). The purpose of ASU 2025-10 is to establish authoritative guidance on the accounting for government grants received by businesses, requiring recognition when it is probable that conditions will be met and funds received. Grants are to be recognized when it is probable that a business will comply with the conditions stipulated in the grant agreement and will receive the funds. Asset-related grants are to be recognized on the balance sheet using either a deferred income approach or by reducing the asset's cost basis. Income-related grants are to be recognized in the income statement either as other income or by reducing the related expense. ASU 2025-10 is effective for annual periods beginning after December 15, 2028 (for public business entities). Early adoption is permitted. Tri- State is evaluating the adoption of this update and its impact to its consolidated financial statements.

The accompanying unaudited consolidated financial statements, which represent the consolidated financial statements of Tri-State Generation and Transmission Association, Inc. (“Tri-State”) and its wholly owned and majority-owned subsidiaries, have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. These unaudited consolidated financial statements should be read in conjunction with the financial statements and notes thereto included in Tri-State's annual report on Form 10-K for the year ended December 31, 2025 filed with the SEC. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair presentation, have been included. Tri-State's consolidated financial position as of March 31, 2026, results of operations for the three months ended March 31, 2026 and 2025, and cash flows for the three months ended March 31, 2026 and 2025 are not necessarily indicative of the results that may be expected for an entire year or any other period.

Tri-State is a taxable wholesale electric power generation and transmission cooperative operating on a not-for-profit basis serving large portions of Colorado, Nebraska, New Mexico and Wyoming. Tri-State was incorporated under the laws of the State of Colorado in 1952. As of March 31, 2026, Tri-State had forty electric distribution member systems ("Utility Members") who are Class A - utility full requirements members to which it provides power pursuant to long-term wholesale electric service contracts. On April 1, 2026, La Plata Electric Association, Inc. ("LPEA") withdrew from membership in Tri-State. See Note 20 - Subsequent Events. Tri-State has three non-utility members (“Non-Utility Members”). Tri-State's Class A Utility Members and Non-Utility Members are collectively referred to as its “Members.”

Tri-State provides wholesale power to its Utility Members at rates determined by its Board of Directors ("Board"), subject to Federal Energy Regulatory Commission (“FERC”) approval or acceptance. Rates are designed to recover all costs and provide margins to increase Utility Members' equity and to meet certain financial covenants, including a debt service ratio ("DSR") requirement and equity to capitalization ratio ("ECR") requirement.

The accompanying financial statements reflect the consolidated accounts of Tri-State, its wholly-owned and majority-owned subsidiaries, and certain variable interest entities for which Tri-State or its subsidiaries are the primary beneficiaries. See Note 18 – Variable Interest Entities. Tri-State's consolidated financial statements also include its undivided interests in jointly owned facilities. All significant intercompany balances and transactions have been eliminated in consolidation.

In November 2024, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures. ASU 2024-03 requires a public business entity to disclose in a tabular format, on an annual and interim basis, purchases of inventory, employee compensation, depreciation, intangible asset amortization and depletion for each income statement line item that contains those expenses in the notes to the financial statements. Specified expenses, gains and losses that are already disclosed under existing GAAP are also required to be included in the disaggregated income statement expense line item disclosures and any remaining amounts need to be described qualitatively. Separate disclosures of total selling expenses and an entity's definition of those expenses are also required. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026, and interim periods within fiscal years beginning after December 15, 2027. Early adoption is permitted. Entities may apply the guidance prospectively or retrospectively. In January 2025, the FASB issued ASU 2025-01 to clarify the effective date of the ASU 2024-03 disaggregation disclosures requiring public companies to adopt the update beginning after December 15, 2026, and for interim periods within annual reporting periods beginning after December 15, 2027, while specifying that initial adoption should in in annual, not interim reporting. Tri-State is evaluating the adoption of these updates and its impact to its consolidated financial statements.