v3.26.3
Business Segments - Schedule of Segment Presentation for the Consolidated Statements of Operations and Consolidated Balance Sheets (Details) - USD ($)
$ in Thousands
 3 Months Ended
Aug. 31, 2026
Aug. 31, 2025
May 31, 2026
May 31, 2025
Results of operations:        
Interest income $ 454,456 $ 447,446    
Interest expense (378,486) (376,469)    
Derivative cash settlements interest income (expense) 0 0    
Interest expense (378,486) (376,469)    
Net interest income 75,970 70,977    
Provision for credit losses (3,875) (1,587)    
Net interest income after provision for credit losses 72,095 69,390    
Non-interest income:        
Fee and other income 7,874 7,075    
Derivative gains (losses):        
Derivative forward value gains (losses) 82,586 (52,471)    
Derivative gains (losses) 96,616 (32,204)    
Investment securities gains 1,639 1,445    
Total non-interest income (loss) 106,129 (23,684)    
Non-interest expense:        
Salaries and employee benefits (20,221) (19,976)    
Depreciation and amortization (3,748) (3,394)    
Other non-interest expense (18,147) (17,674)    
Total non-interest expense (42,116) (41,044)    
Income before income taxes 136,108 4,662    
Income tax (provision) benefit (682) 20    
Net income 135,426 4,682    
Assets:        
Total loans outstanding 38,317,658 37,552,708 $ 38,403,415  
Deferred loan origination costs 19,660 16,893    
Loans to members 38,337,318 37,569,601 38,422,128  
Less: Allowance for credit losses (33,822) (42,202) (29,947) $ (40,615)
Loans to members, net 38,303,496 37,527,399 38,392,181  
Other assets 1,265,330 1,321,319    
Total assets 39,568,826 38,848,718 $ 39,704,347  
Interest rate swaps        
Results of operations:        
Derivative cash settlements interest income (expense) 14,030 20,267    
Derivative gains (losses):        
Derivative cash settlements interest income 14,030 20,267    
Derivative forward value gains (losses) 82,586 (52,471)    
Derivative gains (losses) 96,616 (32,204)    
Operating Segments        
Results of operations:        
Interest income 473,908 467,696    
Interest expense (397,938) (396,719)    
Derivative cash settlements interest income (expense) 14,030 20,267    
Interest expense (383,908) (376,452)    
Net interest income 90,000 91,244    
Provision for credit losses (6,117) (2,089)    
Net interest income after provision for credit losses 83,883 89,155    
Non-interest income:        
Fee and other income 12,790 10,536    
Derivative gains (losses):        
Derivative gains (losses) 0 0    
Investment securities gains 1,639 1,445    
Total non-interest income (loss) 14,429 11,981    
Non-interest expense:        
Salaries and employee benefits (20,221) (19,976)    
Depreciation and amortization (3,748) (3,394)    
Other non-interest expense (20,821) (20,633)    
Total non-interest expense (44,790) (44,003)    
Income before income taxes 53,522 57,133    
Income tax (provision) benefit (682) 20    
Net income 52,840 57,153    
Assets:        
Total loans outstanding 40,001,566 39,212,929    
Deferred loan origination costs 19,660 16,893    
Loans to members 40,021,226 39,229,822    
Less: Allowance for credit losses (41,755) (48,290)    
Loans to members, net 39,979,471 39,181,532    
Other assets 1,280,872 1,337,413    
Total assets 41,260,343 40,518,945    
Operating Segments | Interest rate swaps        
Derivative gains (losses):        
Derivative cash settlements interest income 0 0    
Derivative forward value gains (losses) 0 0    
Reclasses and Adjustments        
Results of operations:        
Interest income 0 0    
Interest expense 0 0    
Derivative cash settlements interest income (expense) (14,030) (20,267)    
Interest expense (14,030) (20,267)    
Net interest income (14,030) (20,267)    
Provision for credit losses 0 0    
Net interest income after provision for credit losses (14,030) (20,267)    
Non-interest income:        
Fee and other income 0 0    
Derivative gains (losses):        
Derivative gains (losses) 96,616 (32,204)    
Investment securities gains 0 0    
Total non-interest income (loss) 96,616 (32,204)    
Non-interest expense:        
Salaries and employee benefits 0 0    
Depreciation and amortization 0 0    
Other non-interest expense 0 0    
Total non-interest expense 0 0    
Income before income taxes 82,586 (52,471)    
Income tax (provision) benefit 0 0    
Net income 82,586 (52,471)    
Assets:        
Total loans outstanding 0 0    
Deferred loan origination costs 0 0    
Loans to members 0 0    
Less: Allowance for credit losses 0 0    
Loans to members, net 0 0    
Other assets 0 0    
Total assets 0 0    
Reclasses and Adjustments | Interest rate swaps        
Derivative gains (losses):        
Derivative cash settlements interest income 14,030 20,267    
Derivative forward value gains (losses) 82,586 (52,471)    
Intersegment Eliminations        
Results of operations:        
Interest income (19,452) (20,250)    
Interest expense 19,452 20,250    
Derivative cash settlements interest income (expense) 0 0    
Interest expense 19,452 20,250    
Net interest income 0 0    
Provision for credit losses 2,242 502    
Net interest income after provision for credit losses 2,242 502    
Non-interest income:        
Fee and other income (4,916) (3,461)    
Derivative gains (losses):        
Derivative gains (losses) 0 0    
Investment securities gains 0 0    
Total non-interest income (loss) (4,916) (3,461)    
Non-interest expense:        
Salaries and employee benefits 0 0    
Depreciation and amortization 0 0    
Other non-interest expense 2,674 2,959    
Total non-interest expense 2,674 2,959    
Income before income taxes 0 0    
Income tax (provision) benefit 0 0    
Net income 0 0    
Assets:        
Total loans outstanding (1,683,908) (1,660,221)    
Deferred loan origination costs 0 0    
Loans to members (1,683,908) (1,660,221)    
Less: Allowance for credit losses 7,933 6,088    
Loans to members, net (1,675,975) (1,654,133)    
Other assets (15,542) (16,094)    
Total assets (1,691,517) (1,670,227)    
Intersegment Eliminations | Interest rate swaps        
Derivative gains (losses):        
Derivative cash settlements interest income 0 0    
Derivative forward value gains (losses) 0 0    
CFC | Operating Segments        
Results of operations:        
Interest income 451,601 444,745    
Interest expense (378,395) (376,377)    
Derivative cash settlements interest income (expense) 14,099 20,294    
Interest expense (364,296) (356,083)    
Net interest income 87,305 88,662    
Provision for credit losses (3,875) (1,587)    
Net interest income after provision for credit losses 83,430 87,075    
Non-interest income:        
Fee and other income 8,638 8,445    
Derivative gains (losses):        
Derivative gains (losses) 0 0    
Investment securities gains 1,639 1,445    
Total non-interest income (loss) 10,277 9,890    
Non-interest expense:        
Salaries and employee benefits (20,161) (19,906)    
Depreciation and amortization (3,748) (3,394)    
Other non-interest expense (17,165) (16,623)    
Total non-interest expense (41,074) (39,923)    
Income before income taxes 52,633 57,042    
Income tax (provision) benefit 0 0    
Net income 52,633 57,042    
Assets:        
Total loans outstanding 38,303,948 37,538,412    
Deferred loan origination costs 19,660 16,893    
Loans to members 38,323,608 37,555,305    
Less: Allowance for credit losses (33,822) (42,202)    
Loans to members, net 38,289,786 37,513,103    
Other assets 1,249,536 1,305,157    
Total assets 39,539,322 38,818,260    
CFC | Operating Segments | Interest rate swaps        
Derivative gains (losses):        
Derivative cash settlements interest income 0 0    
Derivative forward value gains (losses) 0 0    
NCSC | Operating Segments        
Results of operations:        
Interest income 22,307 22,951    
Interest expense (19,543) (20,342)    
Derivative cash settlements interest income (expense) (69) (27)    
Interest expense (19,612) (20,369)    
Net interest income 2,695 2,582    
Provision for credit losses (2,242) (502)    
Net interest income after provision for credit losses 453 2,080    
Non-interest income:        
Fee and other income 4,152 2,091    
Derivative gains (losses):        
Derivative gains (losses) 0 0    
Investment securities gains 0 0    
Total non-interest income (loss) 4,152 2,091    
Non-interest expense:        
Salaries and employee benefits (60) (70)    
Depreciation and amortization 0 0    
Other non-interest expense (3,656) (4,010)    
Total non-interest expense (3,716) (4,080)    
Income before income taxes 889 91    
Income tax (provision) benefit (682) 20    
Net income 207 111    
Assets:        
Total loans outstanding 1,697,618 1,674,517    
Deferred loan origination costs 0 0    
Loans to members 1,697,618 1,674,517    
Less: Allowance for credit losses (7,933) (6,088)    
Loans to members, net 1,689,685 1,668,429    
Other assets 31,336 32,256    
Total assets 1,721,021 1,700,685    
NCSC | Operating Segments | Interest rate swaps        
Derivative gains (losses):        
Derivative cash settlements interest income 0 0    
Derivative forward value gains (losses) $ 0 $ 0