Advances and Other Receivables, Net - Purchase Discount (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Servicing Advances
Balance - beginning of period	$ 205
Addition from acquisition	19
Utilization of purchase discounts	(55)
Balance - end of period	169
Receivables from Agencies, Investors and Prior Servicers
Balance - beginning of period	48
Addition from acquisition	0
Utilization of purchase discounts	0
Balance - end of period	$ 48