Loan Sales and Servicing Activities - Summary of Cash Flows with Transferees (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows:
Sales proceeds	$ 84,345,379	$ 154,450,942	$ 102,840,312
Servicing fees received	931,315	840,104	$ 678,142
Period end information:
Unpaid principal balance of loans outstanding	295,032,674	254,524,015
30-89 days	11,019,194	6,129,597
90 days or more - Not in foreclosure	6,548,849	8,399,299
90 days or more - In foreclosure	834,155	715,016
90 days or more - Foreclosed	12,905	6,900
Bankruptcy	1,143,484	1,039,362
30-89 days delinquent under CARES Act	950,172	1,020,290
90 days or more delinquent not in foreclosure under CARES Act	2,934,718	2,550,703
Total delinquent loans in COVID-19 pandemic related forbearance	$ 3,884,890	$ 3,570,993