Summary of Significant Accounting Policies (Policies)	3 Months Ended
Aug. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
The Company	The CompanyNational Rural Utilities Cooperative Finance Corporation (“CFC”) is a tax-exempt, member-owned cooperative association incorporated under the laws of the District of Columbia in April 1969. CFC’s principal purpose is to provide its members with financing to supplement the loan programs of the Rural Utilities Service (“RUS”) of the United States Department of Agriculture (“USDA”). CFC makes loans to its rural electric members so they can acquire, construct and operate electric distribution systems, electric generation and transmission (“power supply”) systems and related facilities. CFC also provides its members and associates with credit enhancements in the form of letters of credit and guarantees of debt obligations. As a cooperative, CFC is owned by and exclusively serves its membership, which consists of not-for-profit entities or subsidiaries or affiliates of not-for-profit entities.
Basis of Presentation	Basis of Presentation and Use of Estimates The accompanying unaudited interim consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”). These consolidated financial statements include the accounts of CFC and variable interest entities (“VIEs”) where CFC is the primary beneficiary. National Cooperative Services Corporation (“NCSC”) and Rural Telephone Finance Cooperative (“RTFC”) are VIEs that are required to be consolidated by CFC. NCSC is a taxable member-owned cooperative that may provide financing to members of CFC, government or quasi-government entities which own electric utility systems that meet the Rural Electrification Act definition of “rural,” and for-profit and nonprofit entities that are owned, operated or controlled by, or provide significant benefits to certain members of CFC. RTFC is a taxable Subchapter T cooperative association that provides financing for its rural telecommunications members and their affiliates. All intercompany balances and transactions have been eliminated. Unless stated otherwise, references to “we,” “our” or “us” relate to CFC and its consolidated entities.
Use of Estimates	The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts and related disclosures during the period. Management’s most significant estimates and assumptions involve determining the allowance for credit losses. These estimates are based on information available as of the date of the consolidated financial statements. While management makes its best judgments, actual amounts or results could differ from these estimates. In the opinion of management, these unaudited interim financial statements reflect all adjustments of a normal, recurring nature that are necessary for the fair statement of results for the periods presented.
New Accounting Standards Adopted in Fiscal Year 2024	New Accounting Standards Adopted in Fiscal Year 2024 Financial Instruments-Credit Losses, Troubled Debt Restructurings (“TDRs”) and Vintage Disclosures In March 2022, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2022-02, Financial Instruments—Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures, which addresses and amends areas identified by the FASB as part of its post-implementation review of the accounting standard that introduced the current expected credit losses (“CECL”) model. The amendments eliminate the accounting guidance for troubled debt restructurings (“TDR”) by creditors that have adopted the CECL model and enhance the disclosure requirements for loan refinancings and restructurings made with borrowers experiencing financial difficulty. In addition, the amendments require disclosure of current-period gross write-offs for financing receivables and net investment in leases by year of origination in the vintage disclosures. ASU 2022-02 is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years for entities, such as CFC, that have adopted the CECL accounting standard. We adopted the guidance on June 1, 2023 using the prospective adoption method. Accordingly, we will continue to account for existing TDR loans pursuant to the prior TDR accounting guidance until the loans are subsequently modified or settled, and to provide the disclosure required for TDR loans for the comparative periods prior to the adoption. While the guidance resulted in expanded disclosures, it did not have an impact on our consolidated results of operation, financial condition or liquidity from adoption of this accounting standard.
Fair Value Measurement	Fair value, also referred to as an exit price, is defined as the price that would be received for an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. The fair value accounting guidance provides a three-level fair value hierarchy for classifying financial instruments. This hierarchy is based on the markets in which the assets or liabilities trade and whether the inputs to the valuation techniques used to measure fair value are observable or unobservable. The fair value measurement of a financial asset or liability is assigned a level based on the lowest level of any input that is significant to the fair value measurement in its entirety. The levels, in priority order based on the extent to which observable inputs are available to measure fair value, are Level 1, Level 2 and Level 3. The accounting guidance for fair value measurements requires that we maximize the use of observable inputs and minimize the use of unobservable inputs in determining fair value.
Transfers Between Levels	Transfers Between Levels We monitor the availability of observable market data to assess the appropriate classification of financial instruments within the fair value hierarchy and transfer between Level 1, Level 2, and Level 3 accordingly. Observable market data includes but is not limited to quoted prices and market transactions. Changes in economic conditions or market liquidity generally will drive changes in availability of observable market data. Changes in availability of observable market data, which also may result in changes in the valuation technique used, are generally the cause of transfers between levels. We did not have any transfers into or out of Level 3 of the fair value hierarchy during the three months ended August 31, 2023 and 2022.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Aug. 31, 2023

Organization, Consolidation and Presentation of Financial Statements [Abstract]

The CompanyNational Rural Utilities Cooperative Finance Corporation (“CFC”) is a tax-exempt, member-owned cooperative association incorporated under the laws of the District of Columbia in April 1969. CFC’s principal purpose is to provide its members with financing to supplement the loan programs of the Rural Utilities Service (“RUS”) of the United States Department of Agriculture (“USDA”). CFC makes loans to its rural electric members so they can acquire, construct and operate electric distribution systems, electric generation and transmission (“power supply”) systems and related facilities. CFC also provides its members and associates with credit enhancements in the form of letters of credit and guarantees of debt obligations. As a cooperative, CFC is owned by and exclusively serves its membership, which consists of not-for-profit entities or subsidiaries or affiliates of not-for-profit entities.

Basis of Presentation

Basis of Presentation and Use of Estimates

The accompanying unaudited interim consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States (“U.S. GAAP”). These consolidated financial statements include the accounts of CFC and variable interest entities (“VIEs”) where CFC is the primary beneficiary. National Cooperative Services Corporation (“NCSC”) and Rural Telephone Finance Cooperative (“RTFC”) are VIEs that are required to be consolidated by CFC. NCSC is a taxable member-owned cooperative that may provide financing to members of CFC, government or quasi-government entities which own electric utility systems that meet the Rural Electrification Act definition of “rural,” and for-profit and nonprofit entities that are owned, operated or controlled by, or provide significant benefits to certain members of CFC. RTFC is a taxable Subchapter T cooperative association that provides financing for its rural telecommunications members and their affiliates. All intercompany balances and transactions have been eliminated. Unless stated otherwise, references to “we,” “our” or “us” relate to CFC and its consolidated entities.

Use of Estimates

The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts and related disclosures during the period. Management’s most significant estimates and assumptions involve determining the allowance for credit losses. These estimates are based on information available as of the date of the consolidated financial statements. While management makes its best judgments, actual amounts or results could differ from these estimates. In the opinion of management, these unaudited interim financial statements reflect all adjustments of a normal, recurring nature that are necessary for the fair statement of results for the periods presented.

New Accounting Standards Adopted in Fiscal Year 2024

Financial Instruments-Credit Losses, Troubled Debt Restructurings (“TDRs”) and Vintage Disclosures

In March 2022, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2022-02, Financial Instruments—Credit Losses (Topic 326): Troubled Debt Restructurings and Vintage Disclosures, which addresses and amends areas identified by the FASB as part of its post-implementation review of the accounting standard that introduced the current expected credit losses (“CECL”) model. The amendments eliminate the accounting guidance for troubled debt restructurings (“TDR”) by creditors that have adopted the CECL model and enhance the disclosure requirements for loan refinancings and restructurings made with borrowers experiencing financial difficulty. In addition, the amendments require disclosure of current-period gross write-offs for financing receivables and net investment in leases by year of origination in the vintage disclosures. ASU 2022-02 is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years for entities, such as CFC, that have adopted the CECL accounting standard. We adopted the guidance on June 1, 2023 using the prospective adoption method. Accordingly, we will continue to account for existing TDR loans pursuant to the prior TDR accounting guidance until the loans are subsequently modified or settled, and to provide the disclosure required for TDR loans for the comparative periods prior to the adoption. While the guidance resulted in expanded disclosures, it did not have an impact on our consolidated results of operation, financial condition or liquidity from adoption of this accounting standard.

Fair Value Measurement

Fair value, also referred to as an exit price, is defined as the price that would be received for an asset or paid to transfer a liability in an orderly transaction between market participants on the measurement date. The fair value accounting guidance provides a three-level fair value hierarchy for classifying financial instruments. This hierarchy is based on the markets in which the assets or liabilities trade and whether the inputs to the valuation techniques used to measure fair value are observable or unobservable. The fair value measurement of a financial asset or liability is assigned a level based on the lowest level of any input that is significant to the fair value measurement in its entirety. The levels, in priority order based on the extent to which observable inputs are available to measure fair value, are Level 1, Level 2 and Level 3. The accounting guidance for fair value measurements requires that we maximize the use of observable inputs and minimize the use of unobservable inputs in determining fair value.

Transfers Between Levels

We monitor the availability of observable market data to assess the appropriate classification of financial instruments within the fair value hierarchy and transfer between Level 1, Level 2, and Level 3 accordingly. Observable market data includes but is not limited to quoted prices and market transactions. Changes in economic conditions or market liquidity generally will drive changes in availability of observable market data. Changes in availability of observable market data, which also may result in changes in the valuation technique used, are generally the cause of transfers between levels. We did not have any transfers into or out of Level 3 of the fair value hierarchy during the three months ended August 31, 2023 and 2022.