Mortgage Servicing Rights and Related Liabilities - MSRs and Related Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Mortgage Servicing Rights [Line Items]
Forward MSRs - fair value	$ 3,665.0
Mortgage servicing rights	3,676.0
Mortgage servicing liabilities - amortized cost	71.0
MSR related liabilities - nonrecourse	1,216.0
Mortgage Servicing Rights
Mortgage Servicing Rights [Line Items]
Forward MSRs - fair value	3,665.0
Reverse MSRs - amortized cost	11.0
Mortgage servicing rights	3,676.0
Mortgage servicing liabilities - amortized cost	71.0
Mortgage Servicing Right Liability
Mortgage Servicing Rights [Line Items]
Excess spread financing - fair value	1,184.0
Mortgage servicing rights financing - fair value	32.0
MSR related liabilities - nonrecourse	$ 1,216.0
Predecessor
Mortgage Servicing Rights [Line Items]
Forward MSRs - fair value		$ 2,937.0
Mortgage servicing rights		2,941.0
Mortgage servicing liabilities - amortized cost		41.0
Mortgage servicing rights financing - fair value		9.5
MSR related liabilities - nonrecourse		1,006.0
Predecessor \| Mortgage Servicing Rights
Mortgage Servicing Rights [Line Items]
Forward MSRs - fair value		2,937.0
Reverse MSRs - amortized cost		4.0
Mortgage servicing rights		2,941.0
Mortgage servicing liabilities - amortized cost		41.0
Predecessor \| Mortgage Servicing Right Liability
Mortgage Servicing Rights [Line Items]
Excess spread financing - fair value		996.0
Mortgage servicing rights financing - fair value		10.0
MSR related liabilities - nonrecourse		$ 1,006.0

Excess Spread Financing, Fair Value Disclosure

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- Definition

Mortgage Servicing Rights Liability Resulting from Sale or Securitization of Servicer Advances, Rights not Accounted for as a Sale

+ References

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Mortgage Servicing Rights [Line Items]

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Mortgage Serving Rights Liability, carried at fair value

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- Definition

Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

+ References

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Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

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Amortized amount of contract to service financial assets under which estimated future revenues from contractually specified servicing fees, late charges, and other ancillary revenue are not expected to adequately compensate the servicer for performing the servicing.

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