Payables and Other Liabilities - Repurchase Reserves (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Loans Subject to Repurchase Reserve [Roll Forward]
Balance - beginning of period	$ 8
Provisions	8
Releases	0
Charge-offs	0
Balance - end of period	$ 16
Predecessor
Loans Subject to Repurchase Reserve [Roll Forward]
Balance - beginning of period		$ 9
Provisions		1
Releases		(1)
Charge-offs		0
Balance - end of period		$ 9