Nominal or face amount used to calculate payments on the derivative asset.

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Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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Aggregate net fair value of all derivative instruments designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

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Nominal or face amount used to calculate payments on the derivative liability.

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Derivative Financial Instruments - Derivative Instruments (Details) - USD ($) $ in Millions	2 Months Ended	7 Months Ended	9 Months Ended
	Sep. 30, 2018	Jul. 31, 2018	Sep. 30, 2019
Derivatives, Fair Value [Line Items]
Derivative instruments at fair value, less than	$ 0.1	$ 0.1	$ 0.1
Derivative Assets \| Loan sale commitments
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	428.0		1,508.0
Fair Value - Asset	6.9		35.3
Recorded Gains/(Losses)	(3.7)		9.4
Derivative Assets \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	1,765.0		4,964.0
Fair Value - Asset	57.8		143.9
Recorded Gains/(Losses)	(1.8)		84.1
Derivative Assets \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	3,040.0		3,054.0
Fair Value - Asset	12.2		7.7
Recorded Gains/(Losses)	9.0		5.9
Derivative Assets \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	228.0		1,397.0
Fair Value - Asset	1.7		18.2
Recorded Gains/(Losses)	0.5		16.5
Derivative Assets \| Treasury futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	65.0
Fair Value - Asset	0.0
Recorded Gains/(Losses)	0.0
Derivative Assets \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Asset	20.0		6.0
Fair Value - Asset	0.0		0.0
Recorded Gains/(Losses)	0.0		0.0
Derivative Liabilities \| IRLCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	3.0		15.0
Fair Value - Liability	0.0		0.0
Recorded Gains/(Losses)	0.0		0.0
Derivative Liabilities \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	413.0		5,667.0
Fair Value - Liability	0.5		15.9
Recorded Gains/(Losses)	(1.4)		(8.0)
Derivative Liabilities \| LPCs
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	320.0		547.0
Fair Value - Liability	1.5		3.1
Recorded Gains/(Losses)	0.9		2.7
Derivative Liabilities \| Treasury futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	53.0
Fair Value - Liability	0.1
Recorded Gains/(Losses)	0.1
Derivative Liabilities \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Outstanding Notional - Liability	6.0		8.0
Fair Value - Liability	0.0		0.0
Recorded Gains/(Losses)	$ 0.0		$ 0.0
Nationstar Mortgage Holdings Inc. \| Derivative Assets \| Loan sale commitments
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		10.5
Nationstar Mortgage Holdings Inc. \| Derivative Assets \| IRLCs
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		0.4
Nationstar Mortgage Holdings Inc. \| Derivative Assets \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		0.9
Nationstar Mortgage Holdings Inc. \| Derivative Assets \| LPCs
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		0.3
Nationstar Mortgage Holdings Inc. \| Derivative Assets \| Treasury futures
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		(1.8)
Nationstar Mortgage Holdings Inc. \| Derivative Assets \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		0.0
Nationstar Mortgage Holdings Inc. \| Derivative Liabilities \| IRLCs
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		0.0
Nationstar Mortgage Holdings Inc. \| Derivative Liabilities \| Forward MBS trades
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		(1.0)
Nationstar Mortgage Holdings Inc. \| Derivative Liabilities \| LPCs
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		0.1
Nationstar Mortgage Holdings Inc. \| Derivative Liabilities \| Treasury futures
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		(1.3)
Nationstar Mortgage Holdings Inc. \| Derivative Liabilities \| Eurodollar futures
Derivatives, Fair Value [Line Items]
Recorded Gains/(Losses)		$ 0.0