Advances and Other Receivables, Net - Purchase Discount (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Servicing Advances
Balance - beginning of period	$ 117	$ 156	$ 131	$ 205
Addition from acquisition			0	19
Utilization of purchase discounts	(25)	(8)	(39)	(76)
Balance - end of period	92	148	92	148
Receivables from Agencies, Investors and Prior Servicers
Balance - beginning of period	21	48	21	48
Addition from acquisition			0	0
Utilization of purchase discounts	0	0	0	0
Balance - end of period	$ 21	$ 48	$ 21	$ 48