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Loans and Allowances for Credit Losses, Troubled Debt Restructurings (Details) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2022 | Mar. 31, 2021 | Dec. 31, 2021
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Recorded Investment | $ 260,000,000 |  | $ 273,000,000
Troubled Debt Restructuring, Performing in Accordance With Modified Terms | 124,000,000 |  | 141,000,000
Troubled Debt Restructuring, Recorded Balance Modified During the Period | 18,000,000 | $ 13,000,000 |
Troubled Debt Restructuring, Charge-offs | 3,000 | $ 306,000 |
Commercial real estate [Member] |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Specific Allowance | 935,000 |  |
Nonperforming Financial Instruments [Member] | Commercial real estate [Member] |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Recorded Investment | 12,000,000 |  |
Residential mortgage [Member] | Loans to individuals [Member] |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Specific Allowance | 0 |  |
Residential mortgage [Member] | Nonperforming Financial Instruments [Member] | Loans to individuals [Member] |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Recorded Investment | 20,000,000 |  |
US Government Agency Insured Loans [Member] |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Performing in Accordance With Modified Terms | 92,000,000 |  | 97,000,000
US Government Agency Insured Loans [Member] | Residential mortgage [Member] | Performing [Member] | Loans to individuals [Member] |  |  |
Financing Receivable, Troubled Debt Restructuring [Line Items] |  |  |
Troubled Debt Restructuring, Recorded Investment | $ 204,000,000 |  | $ 211,000,000

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- Definition Represents the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructuring and are performing according to modified terms. + References No definition available. + Details
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- Definition 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. + References No definition available. + Details
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- Definition Amount, after troubled debt restructuring, of modified financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524 + Details
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- Definition Amount of financing receivable modified as troubled debt restructuring. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 33 -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554 + Details
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- Definition Reflects the amount of the write-down related to a troubled debt restructuring. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121585226&loc=d3e18845-111554 + Details
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