Advances and Other Receivables - Purchase Discount (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Servicing Advances
Servicing Advances, Discount	$ 19	$ 72
Accretion of Service Advances Discount	(3)	(9)
Servicing Advances, Discount	16	63
Receivables from Agencies, Investors and Prior Servicers
Receivable with Imputed Interest, Discount	8	20
Receivable Discount, Accretion Expense	(4)	(1)
Receivable with Imputed Interest, Discount	$ 12	$ 21