Advances and Other Receivables - Purchase Discount (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Servicing Advances
Balance - beginning of period	$ 63	$ 125	$ 72	$ 131
Utilization of purchase discounts	(37)	(8)	(46)	(14)
Balance - end of period	26	117	26	117
Receivables from Agencies, Investors and Prior Servicers
Balance - beginning of period	20	21	20	21
Utilization of purchase discounts	0	0	(1)	0
Balance - end of period	$ 20	$ 21	$ 21	$ 21