Advances and Other Receivables - Purchase Discount (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Servicing Advances
Balance - beginning of period	$ 31	$ 117	$ 72	$ 131
Utilization of purchase discounts	(1)	(25)	(42)	(39)
Balance - end of period	30	92	30	92
Receivables from Agencies, Investors and Prior Servicers
Balance - beginning of period	13	21	13	21
Utilization of purchase discounts	(7)	0	(8)	0
Balance - end of period	20	21	21	21
Advances And Other Receivables, Servicing Reserves, Write-Offs	$ 37	$ 38	$ 95	$ 49
Document Quarterly Report			true