Acquisitions - Narrative (Details)					3 Months Ended	5 Months Ended	7 Months Ended	12 Months Ended
	Feb. 01, 2019 USD ($)	Oct. 10, 2018	Aug. 01, 2018 USD ($)	Jul. 31, 2018 USD ($) $ / shares shares	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2019 USD ($)	Jul. 13, 2018 USD ($)
Business Acquisition [Line Items]
Preliminary goodwill						$ 23,000,000		$ 120,000,000	$ 23,000,000
Payables and other liabilities						(68,000,000)	$ 88,000,000	(85,000,000)		$ (193,000,000)
Debt issuance costs						68,000,000		10,000,000	68,000,000
Reverse stock split ratio		0.0833
Pacific Union Financial, LLC
Business Acquisition [Line Items]
Cash consideration	$ 116,000,000
Preliminary goodwill	40,000,000
Acquisition costs								4,000,000
Revenue of acquiree								280,000,000
Earnings (loss) of acquiree								140,000,000
Intangible assets acquired								13,000,000
WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Right to receive in cash (in dollars per share) | $ / shares				$ 18			$ 18
Right to receive in shares (shares) | shares				12.7793			12.7793
Acquisition costs				$ 92,000,000			$ 92,000,000
Debt issuance costs				$ 38,000,000			38,000,000
Reverse stock split ratio				0.0833
Nationstar Mortgage Holdings Inc.
Business Acquisition [Line Items]
Cash consideration			$ 1,226,000,000
Preliminary goodwill			65,000,000			10,000,000		65,000,000	10,000,000
Estimated consideration			1,777,000,000
Stock consideration			551,000,000
Decrease in reverse mortgage interests					$ 24,000,000
Reduction in reverse mortgage servicing rights					6,000,000
Increase in mortgage servicing liabilities					37,000,000
Payables and other liabilities					(12,000,000)
Adjustments to goodwill					$ 55,000,000			55,000,000
Intangible assets acquired									103,000,000
Intangible assets			103,000,000
Assurant Mortgage Solutions Group
Business Acquisition [Line Items]
Intangible assets acquired									24,000,000
Nationstar Mortgage Holdings Inc.
Business Acquisition [Line Items]
Preliminary goodwill				$ 72,000,000			72,000,000			$ 72,000,000
Acquisition costs						10,000,000	27,000,000
Adjustments to goodwill							0
Xome Holdings LLC | Assurant Mortgage Solutions Group
Business Acquisition [Line Items]
Cash consideration			38,000,000
Preliminary goodwill						13,000,000			13,000,000
Estimated consideration			$ 53,000,000
Contingent consideration						15,000,000			15,000,000		$ 0
Intangible assets						$ 24,000,000			$ 24,000,000
Final purchase price adjustment								15,000,000
8.125% Due July 2023
Business Acquisition [Line Items]
Face amount												$ 950,000,000
Interest rate												8.125%
9.125% Due July 2026
Business Acquisition [Line Items]
Face amount												$ 750,000,000
Interest rate												9.125%
KKR Capital Markets LLC | WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Acquisition costs				25,000,000			25,000,000
KCM | WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Acquisition costs				7,000,000			$ 7,000,000
Payment for conversion fee				$ 8,000,000
Originations | Pacific Union Financial, LLC
Business Acquisition [Line Items]
Preliminary goodwill	28,000,000
Servicing | Pacific Union Financial, LLC
Business Acquisition [Line Items]
Preliminary goodwill	$ 12,000,000
Salaries, Wages and Benefits | Pacific Union Financial, LLC
Business Acquisition [Line Items]
Acquisition costs								2,000,000
General and Administrative Expense | Pacific Union Financial, LLC
Business Acquisition [Line Items]
Acquisition costs								$ 2,000,000