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Basis of Presentation and Accounting Policies Basis of Presentation and Accounting Policies (Narrative) (Details) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2021 USD ($) segments | Dec. 31, 2020 USD ($)
Commitments to fund additional investments in nonmarketable equity securities |  | $ 1 |
Federal Home Loan Bank Stock |  | 7 | $ 122
Federal Reserve Bank Stock |  | 85 | 85
Net Deferred Income on Originated Loans |  | (102) | (145)
Net fees from PPP loans |  | $ (10) | (55)
Delinquency Status, Period of Unpaid Scheduled Monthly Payment |  | 30 days |
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, after Accumulated Amortization |  | $ 21 | 7
Hosting Arrangement, Service Contract, Implementation Cost, Capitalized, Accumulated Amortization |  | $ 3 | 0
Number of Reporting Units | segments |  | 3 |
Derivative, Notional Amount | [1] | $ 41,638 | 35,185
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 |
Carrying Amount |  |  |
Nonmarketable equity securities | [2] | $ 5 | $ 5
Software |  |  |
Premises and Equipment, Useful Life |  | 5 years |
Minimum | Premises the Corporation owns |  |  |
Premises and Equipment, Useful Life |  | 3 years |
Maximum | Premises the Corporation owns |  |  |
Premises and Equipment, Useful Life |  | 33 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 borrower | Business loans |  |  |
Past Due Period Business Loans Placed On Nonaccrual Status |  | 90 days |
Home equity | Retail loans | Home equity |  |  |
Maximum Past Due Status Junior Lien Home Equity Placed On Nonaccrual Status |  | 90 days |
Home equity | Retail loans | Other consumer |  |  |
Past Due Threshold For Charge-Off |  | 120 days |
Threshold, Days Past Due, Other Consumer Placed On Nonaccrual Status |  | 90 days |
Short-Cut Method | Not Designated as Hedging Instrument [Member] | Interest rate swap | Swaps - fair value - receive fixed/pay floating |  |  |
Derivative, Notional Amount |  | $ 2,100 |
[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.
[2] | Certain investments that are measured at fair value using the net asset value have not been classified in the fair value hierarchy. The fair value amounts presented in the table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheets.

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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 Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123874694&loc=SL6742756-110258 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 35 -Paragraph 54B -URI http://asc.fasb.org/extlink&oid=122636397&loc=SL7495116-110257 + 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 -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 325 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=123599499&loc=d3e63345-112809 + Details
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- Definition Threshold period for when financing receivable is considered past due to write off as uncollectible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919253-210447 + 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 -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 30 -Section 50 -Paragraph 4 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=123392090&loc=d3e45377-112738 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5074-111524 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=84159169&loc=d3e10152-111534 + Details
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