Percentage of allowance for credit loss to total financing receivable outstanding.

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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Amount of allowance for credit loss on financing receivable evaluated on collective basis. Excludes financing receivable evaluated on individual basis.

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Amount of financing receivable collectively evaluated for credit loss. Excludes financing receivable individually evaluated for credit loss.

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

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Amount of unamortized loan commitment, origination, and other costs (fees) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement.

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Allowance for Credit Losses - Schedule of allowance for credit losses components (Details) - USD ($) $ in Thousands	May 31, 2026	May 31, 2025	May 31, 2024	May 31, 2023
Allowance components:
Collective allowance	$ 29,844	$ 31,313
Asset-specific allowance	103	9,302
Total allowance for credit losses	29,947	40,615	$ 48,726	$ 53,094
Loans outstanding
Collectively evaluated loans	38,392,544	37,031,238
Individually evaluated loans	10,871	32,310
Total loans outstanding	$ 38,403,415	$ 37,063,548
Financing receivable, allowance coverage ratios	0.08%	0.11%
Deferred loan origination costs	$ 18,713	$ 16,430
Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.08%	0.08%
Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.95%	28.79%
CFC
Allowance components:
Collective allowance	$ 24,153	$ 25,773
Asset-specific allowance	103	9,256
Total allowance for credit losses	24,256	35,029	42,726	49,424
Loans outstanding
Collectively evaluated loans	36,736,146	35,379,467
Individually evaluated loans	10,871	29,853
Total loans outstanding	$ 36,747,017	$ 35,409,320
Financing receivable, allowance coverage ratios	0.07%	0.10%
Deferred loan origination costs	$ 19,000	$ 16,000
CFC \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.07%	0.07%
CFC \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.95%	31.01%
CFC \| Distribution
Allowance components:
Collective allowance	$ 16,625	$ 18,473
Asset-specific allowance	0	0
Total allowance for credit losses	16,625	18,473	15,954	14,924
Loans outstanding
Collectively evaluated loans	30,081,853	29,258,741
Individually evaluated loans	3,371	3,754
Total loans outstanding	$ 30,085,224	$ 29,262,495
Financing receivable, allowance coverage ratios	0.06%	0.06%
CFC \| Distribution \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.06%	0.06%
CFC \| Distribution \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.00%	0.00%
CFC \| Power supply
Allowance components:
Collective allowance	$ 6,558	$ 6,200
Asset-specific allowance	103	9,256
Total allowance for credit losses	6,661	15,456	25,583	33,306
Loans outstanding
Collectively evaluated loans	6,395,896	5,869,401
Individually evaluated loans	7,500	26,099
Total loans outstanding	$ 6,403,396	$ 5,895,500
Financing receivable, allowance coverage ratios	0.10%	0.26%
CFC \| Power supply \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.10%	0.11%
CFC \| Power supply \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	1.37%	35.46%
CFC \| Statewide and associate
Allowance components:
Collective allowance	$ 970	$ 1,100
Asset-specific allowance	0	0
Total allowance for credit losses	970	1,100	1,189	1,194
Loans outstanding
Collectively evaluated loans	258,397	251,325
Individually evaluated loans	0	0
Total loans outstanding	$ 258,397	$ 251,325
Financing receivable, allowance coverage ratios	0.38%	0.44%
CFC \| Statewide and associate \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.38%	0.44%
CFC \| Statewide and associate \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.00%	0.00%
NCSC
Allowance components:
Collective allowance	$ 5,691	$ 5,540
Asset-specific allowance	0	46
Total allowance for credit losses	5,691	5,586	6,000	3,670
Loans outstanding
Collectively evaluated loans	1,656,398	1,651,771
Individually evaluated loans	0	2,457
Total loans outstanding	$ 1,656,398	$ 1,654,228
Financing receivable, allowance coverage ratios	0.34%	0.34%
NCSC \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.34%	0.34%
NCSC \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.00%	1.87%
NCSC \| Electric
Allowance components:
Collective allowance	$ 4,108	$ 3,818
Asset-specific allowance	0	0
Total allowance for credit losses	4,108	3,818	3,937	2,464
Loans outstanding
Collectively evaluated loans	1,073,794	1,078,763
Individually evaluated loans	0	0
Total loans outstanding	$ 1,073,794	$ 1,078,763
Financing receivable, allowance coverage ratios	0.38%	0.35%
NCSC \| Electric \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.38%	0.35%
NCSC \| Electric \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.00%	0.00%
NCSC \| Telecom
Allowance components:
Collective allowance	$ 1,583	$ 1,722
Asset-specific allowance	0	46
Total allowance for credit losses	1,583	1,768	$ 2,063	$ 1,206
Loans outstanding
Collectively evaluated loans	582,604	573,008
Individually evaluated loans	0	2,457
Total loans outstanding	$ 582,604	$ 575,465
Financing receivable, allowance coverage ratios	0.27%	0.31%
NCSC \| Telecom \| Collective Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.27%	0.30%
NCSC \| Telecom \| Asset-Specific Allowance
Loans outstanding
Financing receivable, allowance coverage ratios	0.00%	1.87%