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Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Details) $ in Millions | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
--- | --- | ---
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | $ 21,843 | $ 19,428
Derivative assets | 780 | 531
Mortgage servicing assets excluded from OREO | 46 |
Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 21,843 | 19,428
Other investments | 90 | 115
Derivative assets | 780 | 531
Fair Value, Nonrecurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans | 76 | 42
Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 11 | 20
Other investments | 13 | 8
Derivative assets | 28 | 8
Level 3 [Member] | Fair Value, Nonrecurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans | 76 | 42
Other Securities [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 11 | 20
Other Securities [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 11 | 20
Other Securities [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 11 | 20
Principal Direct Investments [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | 1 | 1
Principal Direct Investments [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | 1 | 1
Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | 12 |
Valuation Technique, Discounted Cash Flow [Member] | Other Securities [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 11 |
Valuation, Fair Value Of Underlying Collateral [Member] | Level 3 [Member] | Fair Value, Nonrecurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans | 76 | $ 42
Valuation, Market Approach [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential) | 4 |
Valuation, Appraised Value [Member] | Level 3 [Member] | Fair Value, Nonrecurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
OREO | 5 |
Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | 22 |
Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | 1 |
Derivative liabilities | 9 |
Other Contract [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | $ 5 |
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.1391 |
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.1724 |
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.1561 |
Measurement Input, Discount Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Other Securities [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available-for-sale, measurement input | 0.1610 |
Measurement Input, Discount Rate [Member] | Valuation, Fair Value Of Underlying Collateral [Member] | Level 3 [Member] | Fair Value, Nonrecurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans, measurement input | 0 | 0.2000
Measurement Input, Discount Rate [Member] | Valuation, Fair Value Of Underlying Collateral [Member] | Level 3 [Member] | Fair Value, Nonrecurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans, measurement input | 0.6000 | 0.4000
Measurement Input, Discount Rate [Member] | Valuation, Fair Value Of Underlying Collateral [Member] | Level 3 [Member] | Fair Value, Nonrecurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans, measurement input | 0.1000 | 0.2100
Measurement Input, Discount for Lack of Marketability [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.3000 |
Measurement Input, Discount for Lack of Marketability [Member] | Valuation Technique, Discounted Cash Flow [Member] | Other Securities [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available-for-sale, measurement input | 0.3000 |
Measurement Input, Price Volatility [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.4700 |
Measurement Input, Price Volatility [Member] | Valuation Technique, Discounted Cash Flow [Member] | Other Securities [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available-for-sale, measurement input | 0.4300 |
Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.7900 |
Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.9800 |
Measurement Input, Comparability Adjustment [Member] | Valuation, Market Approach [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.9105 |
Measurement Input, Default Rate [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0002 |
Measurement Input, Default Rate [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1.00 |
Measurement Input, Default Rate [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0540 |
Measurement Input, Default Rate [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0002 |
Derivative liabilities, measurement input | 0.0002 |
Measurement Input, Default Rate [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1.00 |
Derivative liabilities, measurement input | 1.00 |
Measurement Input, Default Rate [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0420 |
Derivative liabilities, measurement input | 0.1224 |
Measurement Input, Internal Risk Rating [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 |
Measurement Input, Internal Risk Rating [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 19 |
Measurement Input, Internal Risk Rating [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 9.168 |
Measurement Input, Internal Risk Rating [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 |
Derivative liabilities, measurement input | 1 |
Measurement Input, Internal Risk Rating [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 19 |
Derivative liabilities, measurement input | 19 |
Measurement Input, Internal Risk Rating [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 10.13 |
Derivative liabilities, measurement input | 8.058 |
Measurement Input, Loss Given Default [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0 |
Measurement Input, Loss Given Default [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 |
Measurement Input, Loss Given Default [Member] | Interest Rate [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.492 |
Measurement Input, Loss Given Default [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0 |
Derivative liabilities, measurement input | 0 |
Measurement Input, Loss Given Default [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 |
Derivative liabilities, measurement input | 1 |
Measurement Input, Loss Given Default [Member] | Credit [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.498 |
Derivative liabilities, measurement input | 0.411 |
Measurement Input, Loan Closing Rates [Member] | Other Contract [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Minimum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.3771 |
Measurement Input, Loan Closing Rates [Member] | Other Contract [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Maximum [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.9969 |
Measurement Input, Loan Closing Rates [Member] | Other Contract [Member] | Valuation Technique, Discounted Cash Flow [Member] | Level 3 [Member] | Fair Value, Recurring [Member] | Weighted Average [Member] |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.7933 |

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