Represents the percentage of total loan that is represented by a particular financial receivable category.

No definition available.

Name:	nruc_FinancingReceivableCommercialNetofDeferredIncomePercentage
Namespace Prefix:	nruc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing receivables that are less than 90 days past due but more than 29 days past due as a percentage of total loans.

+ References

No definition available.

+ Details

Name:	nruc_FinancingReceivableRecordedInvestment30To89DaysPastDuePercentage
Namespace Prefix:	nruc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing receivables that are current as a percentage of total loans.

+ References

No definition available.

+ Details

Name:	nruc_FinancingReceivableRecordedInvestmentCurrentPercentage
Namespace Prefix:	nruc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Financing receivables that are equal to or greater than 90 days past due as a percentage of total loans.

+ References

No definition available.

+ Details

Name:	nruc_FinancingReceivableRecordedInvestmentEqualToGreaterThan90DaysPastDuePercentage
Namespace Prefix:	nruc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Recorded Investment in financing receivables that are past due at the balance sheet date as a percentage of total loans.

+ References

No definition available.

+ Details

Name:	nruc_FinancingReceivableRecordedInvestmentPastDuePercentage
Namespace Prefix:	nruc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(e)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestNonaccrual
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of nonaccrual financing receivable balance outstanding that is past due.

+ References

+ Details

Name:	us-gaap_FinancingReceivableNonaccrualPercentPastDue1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(e)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 11: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 12: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 14: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 17: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 18: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 19: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 20: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=nruc_DistributionSystemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=nruc_PowerSupplySystemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=nruc_StatewideAndAssociateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=nruc_ElectricUtilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivablesByIndustryOfCounterpartyTypeAxis=nruc_TelecommunicationsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=nruc_FinancingReceivables30to89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans - Schedule of Payment Status of Loans Outstanding (Details) - USD ($) $ in Thousands	Aug. 31, 2026	May 31, 2026	Aug. 31, 2025
Payment Status of Loans
Amount	$ 38,317,658	$ 38,403,415	$ 37,552,708
Nonaccrual Loans	$ 5,000	$ 7,500
Current, Percentage of total loans	100.00%	100.00%
30-89 days past due, Percentage of total loans	0.00%	0.00%
> 90 days past due, Percentage of total loans	0.00%	0.00%
Total past due, Percentage of total loans	0.00%	0.00%
Total loans outstanding, Percentage of total loans	100.00%	100.00%
Nonaccrual loans, Percentage of total loans	0.01%	0.02%
CFC:
Payment Status of Loans
Amount	$ 36,620,040	$ 36,747,017
Nonaccrual Loans	5,000	7,500
CFC: \| Distribution
Payment Status of Loans
Amount	30,227,582	30,085,224
Nonaccrual Loans	0	0
CFC: \| Power supply
Payment Status of Loans
Amount	6,128,758	6,403,396
Nonaccrual Loans	5,000	7,500
CFC: \| Statewide and associate
Payment Status of Loans
Amount	263,700	258,397
Nonaccrual Loans	0	0
NCSC:
Payment Status of Loans
Amount	1,697,618	1,656,398
Nonaccrual Loans	0	0
NCSC: \| Electric
Payment Status of Loans
Amount	1,111,967	1,073,794
Nonaccrual Loans	0	0
NCSC: \| Telecom
Payment Status of Loans
Amount	585,651	582,604
Nonaccrual Loans	0	0
Current
Payment Status of Loans
Amount	38,317,658	38,403,415
Current \| CFC:
Payment Status of Loans
Amount	36,620,040	36,747,017
Current \| CFC: \| Distribution
Payment Status of Loans
Amount	30,227,582	30,085,224
Current \| CFC: \| Power supply
Payment Status of Loans
Amount	6,128,758	6,403,396
Current \| CFC: \| Statewide and associate
Payment Status of Loans
Amount	263,700	258,397
Current \| NCSC:
Payment Status of Loans
Amount	1,697,618	1,656,398
Current \| NCSC: \| Electric
Payment Status of Loans
Amount	1,111,967	1,073,794
Current \| NCSC: \| Telecom
Payment Status of Loans
Amount	585,651	582,604
Total Past Due
Payment Status of Loans
Amount	0	0
Total Past Due \| CFC:
Payment Status of Loans
Amount	0	0
Total Past Due \| CFC: \| Distribution
Payment Status of Loans
Amount	0	0
Total Past Due \| CFC: \| Power supply
Payment Status of Loans
Amount	0	0
Total Past Due \| CFC: \| Statewide and associate
Payment Status of Loans
Amount	0	0
Total Past Due \| NCSC:
Payment Status of Loans
Amount	0	0
Total Past Due \| NCSC: \| Electric
Payment Status of Loans
Amount	0	0
Total Past Due \| NCSC: \| Telecom
Payment Status of Loans
Amount	0	0
30-89 Days Past Due
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| CFC:
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| CFC: \| Distribution
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| CFC: \| Power supply
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| CFC: \| Statewide and associate
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| NCSC:
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| NCSC: \| Electric
Payment Status of Loans
Amount	0	0
30-89 Days Past Due \| NCSC: \| Telecom
Payment Status of Loans
Amount	0	0
90 Days or More Past Due
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| CFC:
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| CFC: \| Distribution
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| CFC: \| Power supply
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| CFC: \| Statewide and associate
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| NCSC:
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| NCSC: \| Electric
Payment Status of Loans
Amount	0	0
90 Days or More Past Due \| NCSC: \| Telecom
Payment Status of Loans
Amount	$ 0	$ 0