Fair Value - Summary of Reconciliation of the Changes in Fair Value of Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Purchases, issuances, sales and settlements
Gain (loss) on derivatives, net	$ (40.9)	$ (82.5)	$ (8.2)
Capitalization of advances on Ginnie Mae modifications	$ 17.5	9.3	6.4
Total realized and unrealized gains and (losses):
FairValueRecurringBasisUnobservableInputReconciliationAssetGainLossStatementOfIncomeExtensibleListNotDisclosedFlag	Change in fair value (1)
Interest Rate Lock Commitments
Purchases, issuances, sales and settlements
Gain (loss) on derivatives, net	$ 17.8	(6.2)	6.3
Level 3 | Loans Held-For-Sale, Fair Value
Purchases, issuances, sales and settlements
Loans held for investment, at fair value	13.1	4.8	4.5
Capitalization of advances on Ginnie Mae modifications	17.3	9.4	4.4
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Other	6.8	2.9	(0.9)
Loans Held-For-Sale, Fair Value | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	472.9	203.1	32.1
Purchases, issuances, sales and settlements
Purchases and other	872.5	550.9	364.2
Sales	(316.9)	(170.8)	(102.4)
Settlements	(172.3)	(92.2)	(60.5)
Receivables, net	(70.5)	(32.9)	(34.7)
Other assets	(61.9)	(26.8)	(15.2)
Purchases, issuances, sales and settlements, total	274.5	245.3	159.3
Total realized and unrealized gains and (losses):
Included in earnings	32.7	(24.5)	(11.7)
Ending balance	780.1	472.9	203.1
IRLCs | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	(0.5)	5.6
Purchases, issuances, sales and settlements
Issuances	226.4	28.9	39.3
Loans held for sale, at fair value (1)	(159.9)	(26.0)	(64.9)
Purchases, issuances, sales and settlements, total	66.5	3.0	(25.6)
Total realized and unrealized gains and (losses):
Included in earnings	(48.7)
Ending balance	$ 17.3	(0.5)	5.6
Interest Rate Caps | Level 3
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance		5.6	(0.7)
Total realized and unrealized gains and (losses):
Included in earnings		$ (9.1)	(32.0)
Ending balance			$ 5.6