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Mortgage Servicing - Schedule of Activity Related to MSRs - Fair Value Measurement Method (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance	$ 2,632.6	$ 2,327.7	$ 2,466.3	$ 2,272.2
Sales	0.0		0.3
Sales		(108.8)		(209.7)
Recognized on the sale of residential mortgage loans	116.0	61.6	258.9	163.9
Purchases of MSRs	86.7	53.4	234.0	115.3
Servicing transfers and adjustments	0.0	(0.1)	(12.0)	(87.1)
Changes in fair value recognized in earnings:
Changes in valuation inputs or assumptions	(5.6)	(53.0)	1.6	141.4
Realization of cash flows	(66.8)	(57.3)	(186.2)	(172.5)
Ending balance	2,762.9		2,762.9
Assets serviced	189,800.0		189,800.0		$ 170,300.0
Servicing Asset at Fair Value, Period Increase (Decrease)	(72.4)		(184.6)
Servicing assets at fair value, net additions (sales) recognized	202.7		481.3
Derivative, Gain (Loss) on Derivative, Net	21.5	(19.4)	16.3	76.7
MSR valuation adjustments, net	45.0	31.5	111.1	75.8
Total MSR Reserve Fair Value Gains (Losses)	(72.4)	(110.3)	(184.6)	(31.1)
Financing Liability Mortgage Servicing Rights Pledged [Member]
Servicing Asset at Fair Value, Amount [Roll Forward]
Sales	7.9	5.0	22.1	17.7
Changes in fair value recognized in earnings:
Realization of expected cash flows	18.0	17.0	52.8	54.3
Derivative, Gain (Loss) on Derivative, Net	10.6	54.3	25.9	(50.0)
MSR Asset Vehicle LLC | Financing Liability Mortgage Servicing Rights Pledged [Member]
Servicing Asset at Fair Value, Amount [Roll Forward]
Sales	0.2	0.0	0.2	0.0
Fair Value Agency Mortgage Servicing Rights
Changes in fair value recognized in earnings:
Ending balance		2,223.6		2,223.6
Servicing Asset at Fair Value, Period Increase (Decrease)		(110.3)		(31.1)
Servicing assets at fair value, net additions (sales) recognized		$ 6.1		(17.6)
Fair Value Agency Mortgage Servicing Rights | MAV Asset Vehicle LLC
Changes in fair value recognized in earnings:
UPB of MSRs sold				$ 5,500.0
Rithm Capital Corp . and others
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			266.1
Changes in fair value recognized in earnings:
Ending balance	261.3		261.3
Assets serviced	18,600.0		18,600.0		19,000.0
Transferred MSR, Subject To Pledged Liability
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			596.7
Changes in fair value recognized in earnings:
Ending balance	576.7		576.7
Assets serviced	38,800.0		38,800.0		40,500.0
Fair Value GSE Mortgage Servicing Rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			1,902.5
Changes in fair value recognized in earnings:
Ending balance	2,098.8		2,098.8
Assets serviced	145,000.0		145,000.0		129,300.0
Fair Value GNMA Mortgage Servicing Rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			351.6
Changes in fair value recognized in earnings:
Ending balance	465.1		465.1
Assets serviced	24,800.0		24,800.0		19,400.0
Fair Value Non-Agency Mortgage Servicing Rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Beginning balance			212.2
Changes in fair value recognized in earnings:
Ending balance	199.0		199.0
Assets serviced	$ 20,000.0		$ 20,000.0		$ 21,600.0

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Total of property assets serviced as measured by UPB.

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Total MSR Reserve Fair Value Gains (Losses)

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

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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.

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Amount of increase (decrease) in fair value from changes in the inputs used to calculate the fair value 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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