Variable Interest Entities - Information on CFCs Credit Commitments to NCSC and RTFC (Details) - USD ($) $ in Thousands		May 31, 2021		May 31, 2020
Variable Interest Entity [Line Items]
Guarantor Obligations, Current Carrying Value		$ 689,080		$ 820,786
Loans and Leases Receivable, Gross		28,426,961		26,702,380	[1]
Liabilities		28,238,484		27,508,783
Assets		29,638,363		28,157,605
Other Liabilities		52,431		51,656
Long-term Debt		20,603,123		19,712,024
Consolidated variable interest entities
Variable Interest Entity [Line Items]
Total CFC credit commitments		5,500,000		5,500,000
Other Borrowings		1,107,185	[2]	1,062,103
Guarantor Obligations, Current Carrying Value		16,550		9,999
Other credit enhancements		8,386		11,755
Total credit enhancements(2)	[3]	24,936		21,754
Total outstanding commitments		1,132,121		1,083,857
CFC credit commitments available(3)		4,367,879		4,416,143
Guarantor Obligations, Maximum Exposure, Undiscounted		25,000
Loans and Leases Receivable, Gross		1,127,251		1,083,197
Liabilities		30,187		38,803
Assets		$ 1,138,594		$ 1,094,549

[1] The interest rate on unadvanced loan commitments is not set until an advance is made; therefore, all unadvanced long-term loan commitments are reported as variable rate. However, the borrower may select either a fixed or a variable rate when an advance is drawn under a loan commitment.(2) Represents the unpaid principal balance, net of charge-offs and recoveries, of loans as of the end of each period.

[2] Intercompany borrowings payable by NCSC and RTFC to CFC are eliminated in consolidation.

[3] Excludes interest due on these instruments.(3) Represents total CFC credit commitments less outstanding commitments as of each period-end.