NOTES PAYABLE - Borrowings (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2026	Dec. 31, 2025
Due within one year:
Outstanding, Amount	$ 13,163,939	$ 11,271,682
Outstanding, Weighted - average rate	3.55%	3.34%
Medium-term notes due in:
Total due after one year	$ 22,512,240
Total principal net of discounts	35,676,179	$ 30,815,880
Hedging adjustments	(260,078)	6,690
Total	$ 35,416,101	30,822,570
Weighted average rate	3.75%
Discount notes
Due within one year:
Outstanding, Amount	$ 1,707,321	$ 2,614,571
Outstanding, Weighted - average rate	3.73%	3.87%
Average Outstanding, Amount	$ 2,025,074	$ 1,854,488
Average Outstanding, Weighted - average rate (as a percent)	3.76%	4.22%
Medium-term notes
Due within one year:
Outstanding, Amount	$ 2,734,756	$ 2,822,454
Outstanding, Weighted - average rate	3.85%	4.02%
Average Outstanding, Amount	$ 2,788,767	$ 2,901,863
Average Outstanding, Weighted - average rate (as a percent)	3.79%	4.35%
Medium-term notes due in:
Two years	$ 6,567,192	$ 6,641,397
Three years	3,811,393	3,740,471
Four years	4,173,183	2,836,656
Five years	6,263,490	3,889,804
Thereafter	$ 1,696,982	2,435,870
Total due after one year		$ 19,544,198
Total weighted - average rate	3.75%	3.58%
Medium-term notes | Two years
Medium-term notes due in:
Weighted average rate	3.92%	3.65%
Medium-term notes | Three years
Medium-term notes due in:
Weighted average rate	4.07%	3.97%
Medium-term notes | Four years
Medium-term notes due in:
Weighted average rate	3.90%	4.24%
Medium-term notes | Five years
Medium-term notes due in:
Weighted average rate	3.79%	3.71%
Medium-term notes | Thereafter
Medium-term notes due in:
Weighted average rate	3.37%	2.88%
Medium-term notes | Total due after one year
Medium-term notes due in:
Weighted average rate	3.86%	3.71%
Current portion of medium-term notes
Due within one year:
Outstanding, Amount	$ 8,721,862	$ 5,834,657
Outstanding, Weighted - average rate	3.41%	2.77%