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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.

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Net fees from PPP loans

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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.

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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).

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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.

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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.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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