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Basis of Presentation and Accounting Policies Basis of Presentation and Accounting Policies (Narrative) (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 USD ($) segments | Dec. 31, 2022 USD ($)
Federal Home Loan Bank Stock |  | $ 316,550,000 | $ 138,200,000
Federal Reserve Bank Stock |  | 85,271,550 |
Net Deferred Income on Originated Loans |  | $ (94,000,000) | (118,000,000)
Delinquency Status, Period of Unpaid Scheduled Monthly Payment |  | 30 days |
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization |  | $ 61,000,000 | 43,000,000
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, Accumulated Amortization |  | $ 14,000,000 | 5,000,000
Number of Reporting Units | segments |  | 3 |
Derivative, Notional Amount | [1] | $ 70,737,000,000 | $ 67,665,000,000
Defined Benefit Plan Investment Gain Loss Amortization Adjustment, Allowable Percentage |  | 10.00% |
Defined Benefit Plan Actuarial Gain Loss Amortization Adjustment, Allowable Percentage |  | 10.00% |
Defined Benefit Plan Market-related Value Plan Assets, Amortization Period |  | 5 years |
Premises the Corporation owns | Minimum |  |  |
Premises and Equipment, Useful Life |  | 3 years |
Premises the Corporation owns | Maximum |  |  |
Premises and Equipment, Useful Life |  | 33 years |
Furniture and equipment | Minimum |  |  |
Premises and Equipment, Useful Life |  | 3 years |
Furniture and equipment | Maximum |  |  |
Premises and Equipment, Useful Life |  | 8 years |
Leasehold improvements | Maximum |  |  |
Premises and Equipment, Useful Life |  | 10 years |
Software |  |  |
Premises and Equipment, Useful Life |  | 5 years |
Retail loans | Commercial mortgage |  |  |
Past Due Period Residential Mortgage And Home Equity Loans Placed On Nonaccrual Status |  | 90 days |
Past Due Threshold For Charge-Off |  | 180 days |
Commercial | Business loans |  |  |
Past Due Period Business Loans Placed On Nonaccrual Status |  | 90 days |
Consumer | Retail loans | Home equity |  |  |
Maximum Past Due Status Junior Lien Home Equity Placed On Nonaccrual Status |  | 90 days |
Consumer | Retail loans | Other consumer |  |  |
Threshold, Days Past Due, Other Consumer Placed On Nonaccrual Status |  | 90 days |
Past Due Threshold For Charge-Off |  | 120 days |
Swaps - fair value - receive fixed/pay floating | Short-Cut Method | Not Designated as Hedging Instrument [Member] | Interest rate swap |  |  |
Derivative, Notional Amount |  | $ 1,700,000,000 |
[1] | Notional or contractual amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected on the Consolidated Balance Sheets. (b)December 31, 2023 included $2.0 billion of forward starting swaps that will become effective on their contractual start dates in 2024.

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- Definition Minimum percentage by which the actuarial net gain/loss amortization adjustment included in net periodic defined benefit pension expense must exceeds the greater of the projected benefit obligation or the market-related value of plan assets to be included as a component of net periodic defined benefit pension cost. + References No definition available. + Details
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- Definition The maximum number of days principal or interest payments past due at which junior lien home equity loans are placed on nonaccrual status when full collection is in doubt, such as when senior lien position is seriously delinquent. + References No definition available. + Details
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- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1B -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 815 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A + Details
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- Definition Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 325 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481026/942-325-45-1 + Details
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- Definition Amount of deferred interest and fee income, unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of acquired loans. Excludes amounts for loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481569/310-20-50-3 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (a)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481161/840-30-50-4 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481962/310-10-50-4 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1 + Details
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