Fair Value Measurements - Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Assets
Mortgage loans held for sale	$ 1,962	$ 927
Liabilities
Mortgage servicing rights financing	40	29
Recurring Fair Value Measurements
Assets
Mortgage loans held for sale	1,962	927
Mortgage servicing rights	10,035	9,090
Equity investments	9	9
Liabilities
Mortgage servicing rights financing	40	29
Excess spread financing	403	437
Recurring Fair Value Measurements \| IRLCs
Assets
Fair Value	41	21
Recurring Fair Value Measurements \| LPCs
Assets
Fair Value	3	3
Recurring Fair Value Measurements \| Forward MBS trades
Assets
Fair Value	7	22
Fair Value	44	9
Recurring Fair Value Measurements \| Treasury futures
Assets
Fair Value	16	113
Recurring Fair Value Measurements \| Level 1
Assets
Mortgage loans held for sale	0	0
Mortgage servicing rights	0	0
Equity investments	1	1
Liabilities
Mortgage servicing rights financing	0	0
Excess spread financing	0	0
Recurring Fair Value Measurements \| Level 1 \| IRLCs
Assets
Fair Value	0	0
Recurring Fair Value Measurements \| Level 1 \| LPCs
Assets
Fair Value	0	0
Fair Value	0
Recurring Fair Value Measurements \| Level 1 \| Forward MBS trades
Assets
Fair Value	0	0
Fair Value	0	0
Recurring Fair Value Measurements \| Level 1 \| Treasury futures
Assets
Fair Value	0	0
Recurring Fair Value Measurements \| Level 2
Assets
Mortgage loans held for sale	1,897	846
Mortgage servicing rights	0	0
Equity investments	0	0
Liabilities
Mortgage servicing rights financing	0	0
Excess spread financing	0	0
Recurring Fair Value Measurements \| Level 2 \| IRLCs
Assets
Fair Value	0	0
Recurring Fair Value Measurements \| Level 2 \| LPCs
Assets
Fair Value	0	0
Fair Value	0
Recurring Fair Value Measurements \| Level 2 \| Forward MBS trades
Assets
Fair Value	7	22
Fair Value	44	9
Recurring Fair Value Measurements \| Level 2 \| Treasury futures
Assets
Fair Value	16	113
Recurring Fair Value Measurements \| Level 3
Assets
Mortgage loans held for sale	65	81
Mortgage servicing rights	10,035	9,090
Equity investments	8	8
Liabilities
Mortgage servicing rights financing	40	29
Excess spread financing	403	437
Recurring Fair Value Measurements \| Level 3 \| IRLCs
Assets
Fair Value	41	21
Recurring Fair Value Measurements \| Level 3 \| LPCs
Assets
Fair Value	3	3
Fair Value	3
Recurring Fair Value Measurements \| Level 3 \| Forward MBS trades
Assets
Fair Value	0	0
Fair Value	0	0
Recurring Fair Value Measurements \| Level 3 \| Treasury futures
Assets
Fair Value	$ 0	$ 0

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Mortgage Servicing Rights Liability Resulting from Sale or Securitization of Servicer Advances, Rights not Accounted for as a Sale

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Fair value of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, not subject to a master netting arrangement.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Fair value portion of mortgage loans held-for-sale.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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