Notes Payable - Borrowings (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Due within one year:
Current portion of medium-term notes	$ 8,424,580	$ 8,034,175
Weighted - average rate (as a percent)	2.69%	2.31%
Medium-term notes due in:
Two years	$ 4,488,583
Three years	3,373,635
Four years	3,071,804
Five years	1,986,249
Thereafter	3,900,927
Total due after one year	16,821,198
Total principal net of discounts	25,245,778	$ 25,000,199
Hedging adjustments	(408,387)	(531,086)
Total	$ 24,837,391	24,469,113
Weighted - average rate (as a percent)	2.32%
Total weighted - average rate (as a percent)	2.45%
Two years
Medium-term notes due in:
Weighted - average rate (as a percent)	2.04%
Three years
Medium-term notes due in:
Weighted - average rate (as a percent)	1.92%
Four years
Medium-term notes due in:
Weighted - average rate (as a percent)	1.87%
Five years
Medium-term notes due in:
Weighted - average rate (as a percent)	3.66%
Thereafter
Medium-term notes due in:
Weighted - average rate (as a percent)	2.67%
Discount notes
Due within one year:
Current portion of medium-term notes	$ 854,937	$ 565,578
Weighted - average rate (as a percent)	4.68%	3.91%
Short-term debt, average outstanding during the quarter	$ 622,185	$ 1,325,026
Weighted - average rate, average outstanding during the quarter (as a percent)	4.40%	0.96%
Medium-term notes
Due within one year:
Current portion of medium-term notes	$ 2,519,784	$ 2,547,733
Weighted - average rate (as a percent)	3.80%	3.54%
Short-term debt, average outstanding during the quarter	$ 2,584,922	$ 1,442,932
Weighted - average rate, average outstanding during the quarter (as a percent)	3.71%	2.11%
Medium-term notes due in:
Two years		$ 4,072,740
Three years		3,506,480
Four years		2,967,625
Five years		2,361,197
Thereafter		4,057,982
Total due after one year		$ 16,966,024
Weighted - average rate (as a percent)		2.15%
Total weighted - average rate (as a percent)		2.20%
Medium-term notes | Two years
Medium-term notes due in:
Weighted - average rate (as a percent)		1.71%
Medium-term notes | Three years
Medium-term notes due in:
Weighted - average rate (as a percent)		2.10%
Medium-term notes | Four years
Medium-term notes due in:
Weighted - average rate (as a percent)		1.44%
Medium-term notes | Five years
Medium-term notes due in:
Weighted - average rate (as a percent)		3.12%
Medium-term notes | Thereafter
Medium-term notes due in:
Weighted - average rate (as a percent)		2.60%
Current portion of medium-term notes
Due within one year:
Current portion of medium-term notes	$ 5,049,859	$ 4,920,864
Weighted - average rate (as a percent)	1.81%	1.49%