v3.26.3
MSR Valuation Allowance, Net (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
MSRs, at fair value $ 3,360.6   $ 3,360.6   $ 3,208.8 $ 2,825.3 $ 2,632.6 $ 2,466.3
Other financing liabilities, at fair value 613.1   613.1     842.0    
Servicing Asset at Fair Value, Period Increase (Decrease) 114.3   43.8          
Derivative, Gain (Loss) on Derivative, Net 88.2 $ 21.5 132.5 $ 16.3        
MSR valuation adjustments, net (67.3) (45.0) (206.8) (111.1)        
Total MSR Reserve Fair Value Gains (Losses) 114.3 (72.4) 43.8 (184.6)        
Financing Liability Mortgage Servicing Rights Pledged [Member]                
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
Other financing liabilities, at fair value 346.8   346.8     573.2    
MSR                
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
MSRs, at fair value 3,400.0   3,400.0          
Servicing Asset at Fair Value, Change In Fair Value Due To Realization Of Expected Cash Flows (64.6) (48.8) (171.7) (133.3)        
Asset at Fair Value, Changes in Fair Value Resulting from Changes in Assumptions (2.7) 3.8 (35.1) 22.2        
Financing Liability Excess Servicing Spread [Member]                
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
Other financing liabilities, at fair value 266.3   266.3     $ 268.8    
Financing Liability Mortgage Servicing Rights Pledged [Member]                
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
Derivative, Gain (Loss) on Derivative, Net (180.8) 10.6 (242.9) 25.9        
Pledged MSR Liabilities                
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
Servicing Asset at Fair Value, Period Increase (Decrease) 6.0 (10.8) (2.0) (26.7)        
ESS Financing Liabilities                
Assets that Continue to be Recognized, Securitized or Asset-Backed Financing Arrangement Assets and any Other Financial Assets Managed Together [Line Items]                
Total Fair value changes in Servicing liability at fair value $ 5.2 $ 6.0 $ (9.7) $ 20.8