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Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Details) $ in Millions | Mar. 31, 2021 USD ($) | Dec. 31, 2020 USD ($)
--- | --- | ---
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | $ 33,923 | $ 27,556
Derivative assets | 1,524 | 1,798
Mortgage servicing assets excluded from OREO | 61 | 40
Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 33,923 | 27,556
Other investments | 88 | 81
Loans held for sale (residential) | 236 | 264
Derivative assets | 1,524 | 1,798
Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans held for sale (residential) | 8 | 0
Impaired loans | 64 | 108
Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 22 | 13
Other investments | 10 | 14
Loans held for sale (residential) | 0 | 0
Derivative assets | 39 | 91
Level 3 | Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans held for sale (residential) | 8 | 0
Impaired loans | 64 | 108
Valuation Technique, Discounted Cash Flow | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | $ 9 | $ 13
Valuation Technique, Discounted Cash Flow | Measurement Input, Discount Rate | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale, measurement input | 0.1661 | 0.1509
Valuation Technique, Discounted Cash Flow | Measurement Input, Discount Rate | Level 3 | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.1460 | 0.1390
Valuation Technique, Discounted Cash Flow | Measurement Input, Discount Rate | Level 3 | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.1814 | 0.1704
Valuation Technique, Discounted Cash Flow | Measurement Input, Discount Rate | Level 3 | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments, measurement input | 0.1613 | 0.1547
Valuation Technique, Discounted Cash Flow | Measurement Input, Discount Marketability | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale, measurement input | 0.3000 | 0.3000
Other investments, measurement input | 0.3000 | 0.3000
Valuation Technique, Discounted Cash Flow | Measurement Input, Price Volatility | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale, measurement input | 0.5500 | 0.4400
Other investments, measurement input | 0.5200 | 0.5200
Valuation, Market Comparable Pricing | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential) | $ 11 | $ 11
Valuation, Market Comparable Pricing | Level 3 | Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans held for sale (residential) | $ 8 | $ 0
Valuation, Market Comparable Pricing | Measurement Input, Comparability Adjustment | Level 3 | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.0000 | 0.6450
Valuation, Market Comparable Pricing | Measurement Input, Comparability Adjustment | Level 3 | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.9811 | 0.9904
Valuation, Market Comparable Pricing | Measurement Input, Comparability Adjustment | Level 3 | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Loans, net of unearned income (residential), measurement input | 0.9506 | 0.9417
Valuation, Fair Value Of Underlying Collateral | Level 3 | Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans | $ 64 | $ 108
Valuation, Fair Value Of Underlying Collateral | Measurement Input, Discount Rate | Nonrecurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans, measurement input | 0 | 0
Valuation, Fair Value Of Underlying Collateral | Measurement Input, Discount Rate | Nonrecurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans, measurement input | 1.0000 | 1.0000
Valuation, Fair Value Of Underlying Collateral | Measurement Input, Discount Rate | Nonrecurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Impaired loans, measurement input | 0.3200 | 0.3600
Valuation, Appraised Value | Level 3 | Nonrecurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
OREO and other Level 3 assets | $ 11 | $ 16
Interest rate | Valuation Technique, Discounted Cash Flow | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | $ 30 | $ 56
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Default Rate | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0002 | 0.0002
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Default Rate | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Default Rate | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0670 | 0.0790
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Internal Risk Rating | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Internal Risk Rating | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 19 | 19
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Internal Risk Rating | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 9.731 | 9.675
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Loss Given Default | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0 | 0
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Loss Given Default | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Interest rate | Valuation Technique, Discounted Cash Flow | Measurement Input, Loss Given Default | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.485 | 0.483
Credit | Valuation Technique, Discounted Cash Flow | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | $ 1 | $ 1
Derivative liabilities | $ (5) | $ (11)
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Default Rate | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0002 | 0.0002
Derivative liabilities, measurement input | 0.0002 | 0.0002
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Default Rate | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Derivative liabilities, measurement input | 1 | 1
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Default Rate | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.0360 | 0.0470
Derivative liabilities, measurement input | 0.1310 | 0.1545
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Internal Risk Rating | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Derivative liabilities, measurement input | 1 | 1
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Internal Risk Rating | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 19 | 19
Derivative liabilities, measurement input | 19 | 19
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Internal Risk Rating | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 10.281 | 10.478
Derivative liabilities, measurement input | 8.738 | 8.555
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Loss Given Default | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0 | 0
Derivative liabilities, measurement input | 0 | 0
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Loss Given Default | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 1 | 1
Derivative liabilities, measurement input | 1 | 1
Credit | Valuation Technique, Discounted Cash Flow | Measurement Input, Loss Given Default | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.491 | 0.490
Derivative liabilities, measurement input | 0.443 | 0.431
Other | Valuation Technique, Discounted Cash Flow | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets | $ 6 | $ 32
Other | Valuation Technique, Discounted Cash Flow | Measurement Input, Loan Closing Rates | Recurring | Minimum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.3695 | 0.3695
Other | Valuation Technique, Discounted Cash Flow | Measurement Input, Loan Closing Rates | Recurring | Maximum |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.9968 | 0.9968
Other | Valuation Technique, Discounted Cash Flow | Measurement Input, Loan Closing Rates | Recurring | Weighted Average |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Derivative assets, measurement input | 0.7751 | 0.7751
Other securities |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | $ 22 | $ 13
Other securities | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 22 | 13
Other securities | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 22 | 13
Other securities | Valuation Technique, Discounted Cash Flow | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Securities available for sale | 22 | 13
Principal investments, Direct | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | 1 | 1
Principal investments, Direct | Level 3 | Recurring |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |
Other investments | $ 1 | $ 1

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