Transfers and Servicing (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 07, 2021
Transfers and Servicing [Abstract]
Servicing Asset at Fair Value, Amount	$ 698.0	$ 0.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Servicing Assets				$ 1,347.0
Servicing Asset at Fair Value, Additions	763.8	$ 0.0	$ 0.0
Servicing Asset at Fair Value, Disposals	(1,270.7)
Servicing Asset at Fair Value, Changes in Fair Value Resulting from Changes in Valuation Inputs or Changes in Assumptions	(2.5)
Servicing Asset at Fair Value, Other Changes in Fair Value	(139.6)
Continuing Involvement with Transferred Financial Assets, Principal Amount Outstanding	54,347.6
MSR Sales, UPB of underlying loans	97,200.0
MSR Loan Sales, Receivable	82.5
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	138.9
Servicing advances, net	81.6
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 50 basis point Adverse Interest Rate Change	(61.6)
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 50 basis point Favorable Interest Rate Change	39.9
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 50 basis point Discount Rate Increase	(13.3)
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 50 basis point Discount Rate Decrease	13.8
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 1 Percent Increase in Prepayment Speed	(21.5)
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 1 Percent Decrease in Prepayment Speed	23.8
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Increase Cost of Service	(9.6)
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Decrease Cost of Service	9.6
Servicing Assets at Fair Value [Line Items]
Servicing Asset at Fair Value, Disposals	1,270.7
Servicing Contracts
Transfers and Servicing [Abstract]
Servicing Asset at Fair Value, Disposals	(1,300.0)
Servicing Assets at Fair Value [Line Items]
Servicing Asset at Fair Value, Disposals	$ 1,300.0