Indebtedness - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Debt Instrument [Line Items]
Interest Expense	$ 170	$ 110
Advance Facilities \| Servicing
Debt Instrument [Line Items]
Short-Term Debt, Weighted Average Interest Rate, over Time	7.80%	7.20%
Warehouse & MSR Facilities
Debt Instrument [Line Items]
Short-Term Debt, Weighted Average Interest Rate, over Time	7.90%	7.00%
Unsecured Senior Notes
Debt Instrument [Line Items]
Maximum percentage redeemable on unsecured debt	40.00%
Repayments of debt	$ 0	$ 0
Amount of principal amount outstanding repaid	$ 0	$ 0

Debt Instrument, Debt Redemption, Amount Of Principal Redeemed

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