Mortgage Servicing Rights ("MSRs") and Related Liabilities - MSRs and Related Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Mortgage Servicing Rights [Line Items]
Mortgage servicing rights at fair value	$ 3,485
Mortgage servicing rights - fair value and amortized cost	3,500
Mortgage servicing liabilities - amortized cost	79
Excess spread financing - fair value	1,097
Mortgage servicing rights financing - fair value	26	$ 10
MSR related liabilities - nonrecourse at fair value	1,123
Mortgage servicing rights
Mortgage Servicing Rights [Line Items]
Mortgage servicing rights at fair value	3,485
Mortgage servicing right at amortized cost	15
Mortgage servicing rights - fair value and amortized cost	3,500
Mortgage servicing liabilities - amortized cost	$ 79
Predecessor
Mortgage Servicing Rights [Line Items]
Mortgage servicing rights at fair value		2,937
Mortgage servicing rights - fair value and amortized cost		2,941
Mortgage servicing liabilities - amortized cost		41
Excess spread financing - fair value		996
Mortgage servicing rights financing - fair value		10
MSR related liabilities - nonrecourse at fair value		1,006
Predecessor \| Mortgage servicing rights
Mortgage Servicing Rights [Line Items]
Mortgage servicing rights at fair value		2,937
Mortgage servicing right at amortized cost		4
Mortgage servicing rights - fair value and amortized cost		2,941
Mortgage servicing liabilities - amortized cost		$ 41

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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- Definition

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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