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Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Details) | Dec. 31, 2023 USD ($) | Dec. 31, 2022 USD ($)
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Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | $ 181,000,000 | $ 1,024,000,000
Mortgage servicing assets excluded from OREO | 8,000,000 | 0
Fair Value, Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | 181,000,000 | 1,024,000,000
Other investments | 63,000,000 | 77,000,000
Fair Value, Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Collateral dependent loans | 104,000,000 | 17,000,000
Level 3 | Fair Value, Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | 0 | 3,000,000
Insignificant level 3 assets, net of liabilities | 4,000,000 | 1,000,000
Other investments | 2,000,000 | 3,000,000
Level 3 | Fair Value, Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Collateral dependent loans | 104,000,000 | 17,000,000
Principal investments: Direct | Fair Value, Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | 0 | 1,000,000
Principal investments: Direct | Level 3 | Fair Value, Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | 0 | 1,000,000
Market comparable pricing | Level 3 | Fair Value, Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential) | 9,000,000 | 9,000,000
Fair value of underlying collateral | Level 3 | Fair Value, Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Collateral dependent loans | 104,000,000 | 17,000,000
Appraised value | Level 3 | Fair Value, Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
OREO and other assets | 21,000,000 | 14,000,000
Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | $ (2,000,000) | $ 2,000,000
Comparability factor | Market comparable pricing | Level 3 | Fair Value, Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.6267 | 0.6100
Comparability factor | Market comparable pricing | Level 3 | Fair Value, Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.8960 | 0.8658
Comparability factor | Market comparable pricing | Level 3 | Fair Value, Recurring | Weighted-Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.7083 | 0.7221
Probability of default | Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0002 | 0.0002
Probability of default | Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Probability of default | Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring | Weighted-Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0530 | 0.0800
Loss given default | Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0 | 0
Loss given default | Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Loss given default | Interest rate | Discounted cash flows | Level 3 | Fair Value, Recurring | Weighted-Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.48 | 0.49
Credit and liquidity discount | Fair value of underlying collateral | Level 3 | Fair Value, Nonrecurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Collateral dependent loans, measurement input | 0 | 0
Credit and liquidity discount | Fair value of underlying collateral | Level 3 | Fair Value, Nonrecurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Collateral dependent loans, measurement input | 0.1000 | 0.8500
Credit and liquidity discount | Fair value of underlying collateral | Level 3 | Fair Value, Nonrecurring | Weighted-Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Collateral dependent loans, measurement input | 0.0500 | 0.3400

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- Definition Fair value, after the effects of master netting arrangements, of a 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. 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