Loan Sales and Servicing Activities - Summary of Cash Flows with Transferees (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Cash flows:
Sales proceeds	$ 31,267,022	$ 37,268,200
Servicing fees received	204,928	$ 195,782
Period end information:
Unpaid principal balance of loans outstanding	268,886,759		$ 254,524,015
30-89 days	6,219,747		6,129,597
90 days or more - Not in foreclosure	6,565,644		8,399,299
90 days or more - In foreclosure	806,337		715,016
90 days or more - Foreclosed	4,752		6,900
Bankruptcy	1,151,627		1,039,362
30-89 days delinquent under CARES Act	1,080,136		1,020,290
90 days or more delinquent not in foreclosure under CARES Act	2,263,698		2,550,703
Total delinquent loans in COVID-19 pandemic related forbearance	$ 3,343,834		$ 3,570,993