Mortgage Loans Held for Sale and Investment - Reconciliation to Cash Flow (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance - beginning of period	$ 1,631
Mortgage loans originated and purchased, net of fees	6,252
Loans sold	(6,088)
Repurchase of loans out of Ginnie Mae securitizations	364
Transfer of mortgage loans held for sale to advances/accounts receivable, net related to claims	(3)
Net transfer of mortgage loans held for sale from REO in other assets	3
Changes in fair value	10
Other purchase-related activities	1
Balance - end of period	$ 2,170
Predecessor
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance - beginning of period		$ 1,891
Mortgage loans originated and purchased, net of fees		5,088
Loans sold		(5,649)
Repurchase of loans out of Ginnie Mae securitizations		251
Transfer of mortgage loans held for sale to advances/accounts receivable, net related to claims		(3)
Net transfer of mortgage loans held for sale from REO in other assets		8
Changes in fair value		(5)
Other purchase-related activities		8
Balance - end of period		$ 1,589