Fair Value Measurements - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Net fair value of the interest rate lock commitments	$ 7,000,000
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 25 bps	2,000,000
Change in the fair value of the interest rate lock commitments, due to decrease in current interest rates of 50 bps	4,000,000
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 25 bps	3,000,000
Change in the fair value of the interest rate lock commitments, due to increase in current interest rates of 50 bps	6,000,000
Change in fair value of interest rate lock commitments, due to 10% favorable changes in the assumed loan closing rates	1,000,000
Change in fair value of interest rate lock commitments, due to 20% favorable changes in the assumed loan closing rates	1,000,000
Gain resulting from observable price changes	0	$ 4,000,000
Private equity, cumulative observable price change	40,000,000
Private equity, impairment	1,000,000	10,000,000
Private equity, cumulative impairment	35,000,000
Fair value of embedded derivatives	0		$ 0
Gain on embedded derivatives	0	11,000,000
Other Real Estate Owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value adjustment	0	1,000,000
Transfer \| Other Real Estate Owned
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value gains (losses)	0	0
Residential Mortgage
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Fair value changes included in earnings for instruments for which the fair value option was elected	8,000,000	$ 10,000,000
FVO valuation adjustments related to instrument-specific credit risk	$ 1,000,000		$ 1,000,000

Sensitivity analysis of decrease in fair value of derivatives impact of fifty basis point increase in interest rate.

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Sensitivity analysis of decrease in fair value of derivatives impact of twenty five basis point increase in interest rate.

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Sensitivity analysis of increase in fair value of derivatives impact of fifty basis point decrease in interest rate.

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Sensitivity analysis of increase in fair value of derivatives impact of ten percent changes in assumed loan closing rates.

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Sensitivity analysis of increase in fair value of derivatives impact of twenty five basis point decrease in interest rate.

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Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

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Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

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Fair value as of the balance sheet date of the embedded derivative or group of embedded derivatives classified as an asset.

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Increase in the fair value of the embedded derivative or group of embedded derivatives included in earnings in the period.

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Amount of loss from downward price adjustment on investment in equity security without readily determinable fair value.

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Amount of cumulative loss from downward price adjustment on investment in equity security without readily determinable fair value.

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Amount of gain from upward price adjustment on investment in equity security without readily determinable fair value.

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Amount of cumulative gain from upward price adjustment on investment in equity security without readily determinable fair value.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For each line item in the statement of financial position, the amounts of gains and losses from fair value changes included in earnings.

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This item represents the estimated amount of gains or losses included in earnings during the period attributable to changes in instrument-specific credit risk arising from loans and other receivables held as assets.

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Amount of gain (loss) related to nonoperating activities, classified as other.

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