Fair Value Measurements - Quantitative Information about Recurring Level 3 Fair Value Instruments (Details) - Level 3 - Fair Value $ in Millions	Sep. 30, 2022 USD ($) constantPrepaymentRatePerLoan $ / loan optionAdjustedSpreadPerLoan originationPull-throughRatePerLoan	Dec. 31, 2021 USD ($) constantPrepaymentRatePerLoan $ / loan optionAdjustedSpreadPerLoan originationPull-throughRatePerLoan
Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset \| $	$ 1,026	$ 392
Mortgage servicing rights \| Option adjusted spread (in percent) \| Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| optionAdjustedSpreadPerLoan	0.053	0.039
Mortgage servicing rights \| Option adjusted spread (in percent) \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| optionAdjustedSpreadPerLoan	0.216	0.216
Mortgage servicing rights \| Option adjusted spread (in percent) \| Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| optionAdjustedSpreadPerLoan	0.056	0.071
Mortgage servicing rights \| Constant prepayment rate (in percent) \| Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| constantPrepaymentRatePerLoan	0	0
Mortgage servicing rights \| Constant prepayment rate (in percent) \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| constantPrepaymentRatePerLoan	0.101	0.111
Mortgage servicing rights \| Constant prepayment rate (in percent) \| Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| constantPrepaymentRatePerLoan	0.078	0.092
Mortgage servicing rights \| Weighted average cost to service per loan (in USD per loan) \| Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| $ / loan	65	67
Mortgage servicing rights \| Weighted average cost to service per loan (in USD per loan) \| Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| $ / loan	90	90
Mortgage servicing rights \| Weighted average cost to service per loan (in USD per loan) \| Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Servicing asset, measurement input \| $ / loan	68	80
Rate lock commitments (net)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative liabilities \| $	$ (19)
Derivative asset \| $		$ 53
Rate lock commitments (net) \| Origination pull-through rate (in percent) \| Weighted Average
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, measurement input \| originationPull-throughRatePerLoan	0.715	0.728

Value of input used to measure derivative asset.

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