Fair Value Measurements - Unobservable Inputs (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2021
MSR(1)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Average life(3)	8 years	5 years 9 months 18 days
Excess spread financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Average life(3)	6 years 7 months 6 days	5 years 4 months 24 days
Min | MSR(1)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount rate	10.40%	9.50%
Prepayment speed	6.60%	11.70%
Cost to service per loan(2)	$ 59	$ 59
Min | IRLCs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Value of servicing (reflected as a percentage of loan commitment)	(0.003)	(0.007)
Min | Excess spread financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount rate	10.00%	9.50%
Prepayment speed	6.60%	12.80%
Min | Mortgage servicing rights financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Advance financing and counterparty fee rates	5.00%	4.50%
Annual advance recovery rates	16.90%	19.20%
Max | MSR(1)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount rate	13.70%	13.70%
Prepayment speed	13.30%	16.40%
Cost to service per loan(2)	$ 128	$ 168
Max | IRLCs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Value of servicing (reflected as a percentage of loan commitment)	0.044	0.024
Max | Excess spread financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount rate	13.80%	13.80%
Prepayment speed	13.50%	15.20%
Max | Mortgage servicing rights financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Advance financing and counterparty fee rates	8.70%	7.90%
Annual advance recovery rates	22.90%	23.00%
Weighted Average | MSR(1)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount rate	11.40%	10.90%
Prepayment speed	7.40%	13.00%
Cost to service per loan(2)	$ 78	$ 77
Weighted Average | IRLCs
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Value of servicing (reflected as a percentage of loan commitment)	0.021	0.014
Weighted Average | Excess spread financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Discount rate	11.30%	11.20%
Prepayment speed	9.50%	13.40%
Weighted Average | Mortgage servicing rights financing
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Advance financing and counterparty fee rates	7.30%	6.50%
Annual advance recovery rates	18.50%	21.30%