Mortgage Loans Held for Sale and Investment - Reconciliation to Cash Flow (Details) - USD ($) $ in Millions	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2018	Jul. 31, 2018	Dec. 31, 2019	Feb. 01, 2019
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Balance - beginning of period	$ 1,514	$ 1,891	$ 1,631
Loans sold	(9,304)	(13,255)	(41,289)
Mortgage loans originated and purchased, net of fees	8,890	12,319	40,772
Repurchase of loans out of Ginnie Mae securitizations	527	544	2,895
Net transfer of mortgage loans held for sale (to)/from REO in other assets	5	14	34
Changes in fair value	6	(1)	29
Other purchase-related activities	(2)	9	21
Transfer of mortgage loans held for sale to advances and other receivables, net related to claims	(5)	(7)	(16)
Balance - end of period	1,631	$ 1,514	4,077
Pacific Union Financial, LLC
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Mortgage loans held for sale			536	$ 536
Mortgage Loans Held for Investment
Loans Receivable Held-for-sale, Net, Reconciliation to Cash Flow [Roll Forward]
Transfers to mortgage loans held for sale	$ 0		$ (12)