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Significant Group Concentrations of Credit Risk Significant Group Concentrations of Credit Risk (Commercial Real Estate Exposure) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk Threshold - Commercial Real Estate	36.00%
Current loans	$ 49,968	$ 51,717
Real estate construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	3,680	5,083
Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	14,493	13,686
Total commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	18,173	18,769
Total unused commitments	3,130	4,382
Commercial Real Estate business line | Real estate construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	3,358	4,570
Commercial Real Estate business line | Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	6,044	4,727
Other Business Lines Member | Real estate construction loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	322	513
Other Business Lines Member | Commercial mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current loans	$ 8,449	$ 8,959

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- Definition

Concentration Risk Threshold - Commercial Real Estate

+ References

No definition available.

+ Details

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- Definition

Current loans

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- Definition

Reflects unused commitments that have been issued to businesses to acquire real property, develop land for sale or construction thereon, to construct a facility and to provide financing on existing land or a building, which, pursuant to terms of the underlying debt instrument, are secured at a minimum but possibly exclusively by that real property.

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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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

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