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Business Combination, Common Stock, Right To Receive In Shares

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Increase (Decrease) In Mortgage Servicing Liabilities

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Increase (Decrease) In Reverse Mortgage Interests

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Increase (Decrease) In Reverse Mortgage Servicing Rights

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Payment For Conversion Fee Of Convertible Debt

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Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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Amount of increase (decrease) in income that would have been recognized in previous periods if the adjustments to provisional amounts were recognized as of the acquisition date.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase (decrease) from adjustments after acquisition date under purchase accounting of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Acquisitions - Acquisition of Nationstar Mortgage Holdings Inc (Details) $ / shares in Units, $ in Millions				3 Months Ended
	Aug. 01, 2018 USD ($)	Jul. 31, 2018 USD ($) $ / shares shares	Jul. 13, 2018 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Jul. 12, 2018 USD ($)
Business Acquisition [Line Items]
Goodwill				$ 109		$ 23
Reduction in payables and accrued liabilities				217
Goodwill adjustment				55
Nationstar Mortgage Holdings Inc.
Business Acquisition [Line Items]
Cash consideration	$ 1,226
Estimated consideration	1,777
Stock consideration	551
Goodwill	$ 65			65		$ 10
Reduction in reverse mortgage interests				24
Reduction in reverse mortgage servicing rights				6
Increase in mortgage servicing liabilities				37
Reduction in payables and accrued liabilities				12
Goodwill adjustment				55
Accounting adjustments				8
WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Right to receive in shares (in dollars per share) \| $ / shares		$ 18
Right to receive in shares (shares) \| shares		12.7793
Stock split conversion		0.0833
Acquisition costs		$ 27		1	$ 4		$ 92
Debt issuance costs							38
8.125% Due July 2023
Business Acquisition [Line Items]
Debt issued			$ 950
Interest rate			8.125%
9.125% Due July 2026
Business Acquisition [Line Items]
Debt issued			$ 750
Interest rate			9.125%
KCM \| WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Acquisition costs							7
Payment for conversion fee			$ 8
KKR Capital Markets LLC \| WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Acquisition costs							$ 25
Service related, net revenue \| Nationstar Mortgage Holdings Inc.
Business Acquisition [Line Items]
Accounting adjustments				7
Interest income \| Nationstar Mortgage Holdings Inc.
Business Acquisition [Line Items]
Accounting adjustments				$ 1
Predecessor
Business Acquisition [Line Items]
Reduction in payables and accrued liabilities					29
Predecessor \| WMIH Corp And Wand Merger Corporation
Business Acquisition [Line Items]
Acquisition costs					$ 3