Notes Payable - Borrowings (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Due within one year:
Outstanding, Amount	$ 8,330,898	$ 8,034,175
Outstanding, Weighted - average rate (as a percent)	2.87%	2.31%
Medium-term notes due in:
Two years	$ 4,377,382
Three years	3,346,872
Four years	3,109,837
Five years	2,096,324
Thereafter	3,738,098
Total due after one year	16,668,513
Total principal net of discounts	24,999,411	$ 25,000,199
Hedging adjustments	(489,407)	(531,086)
Total	$ 24,510,004	24,469,113
Weighted - average rate (as a percent)	2.58%
Total weighted - average rate (as a percent)	2.68%
Two years
Medium-term notes due in:
Weighted - average rate (as a percent)	2.58%
Three years
Medium-term notes due in:
Weighted - average rate (as a percent)	2.00%
Four years
Medium-term notes due in:
Weighted - average rate (as a percent)	2.18%
Five years
Medium-term notes due in:
Weighted - average rate (as a percent)	3.81%
Thereafter
Medium-term notes due in:
Weighted - average rate (as a percent)	2.73%
Discount notes
Due within one year:
Outstanding, Amount	$ 954,611	$ 565,578
Outstanding, Weighted - average rate (as a percent)	4.91%	3.91%
Average Outstanding, Amount	$ 802,684	$ 1,325,026
Average Outstanding, Weighted - average rate (as a percent)	4.67%	0.96%
Medium-term notes
Due within one year:
Outstanding, Amount	$ 1,921,890	$ 2,547,733
Outstanding, Weighted - average rate (as a percent)	4.21%	3.54%
Average Outstanding, Amount	$ 2,371,610	$ 1,442,932
Average Outstanding, Weighted - average rate (as a percent)	3.86%	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:
Outstanding, Amount	$ 5,454,397	$ 4,920,864
Outstanding, Weighted - average rate (as a percent)	2.05%	1.49%