Payables and Other Liabilities - Repurchase Reserves (Details) - USD ($) $ in Millions	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2019
Loans Subject to Repurchase Reserve [Roll Forward]
Repurchase Reserve	$ 9	$ 9	$ 8
Provisions	3	3	25
Releases	(4)	(3)	(8)
Repurchase Reserve	$ 8	$ 9	$ 25