Credit Quality And Allowance For Credit Losses (Troubled Debt Restructurings) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	$ 73
Business loans | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	43
Business loans | Commercial | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	26
Business loans | Commercial | Real estate construction | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	3
Business loans | Commercial | Commercial mortgage | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	14	[1]
Retail loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	30
Retail loans | Residential mortgage | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	27
Retail loans | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	3
Retail loans | Consumer | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	2	[2]
Retail loans | Consumer | Consumer | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	1
Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	44	[3]
Payment Delay | Business loans | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	43	[3]
Payment Delay | Business loans | Commercial | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	26
Payment Delay | Business loans | Commercial | Real estate construction | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	3
Payment Delay | Business loans | Commercial | Commercial mortgage | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	14
Payment Delay | Retail loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	1
Payment Delay | Retail loans | Residential mortgage | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	0
Payment Delay | Retail loans | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	1
Payment Delay | Retail loans | Consumer | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	1
Payment Delay | Retail loans | Consumer | Consumer | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	0
Interest Rate Reductions
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	29
Interest Rate Reductions | Business loans | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	0
Interest Rate Reductions | Business loans | Commercial | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	0
Interest Rate Reductions | Business loans | Commercial | Real estate construction | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	0
Interest Rate Reductions | Business loans | Commercial | Commercial mortgage | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	0
Interest Rate Reductions | Retail loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	29
Interest Rate Reductions | Retail loans | Residential mortgage | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	27
Interest Rate Reductions | Retail loans | Consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	2
Interest Rate Reductions | Retail loans | Consumer | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	1
Interest Rate Reductions | Retail loans | Consumer | Consumer | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Recorded balance of troubled debt restructuring modified during the period	$ 1

[1] .

[2] .

[3] Primarily represents loan balances where terms were extended by more than an insignificant time period, typically more than 180 days, at or above contractual interest rates. Also includes commercial loans restructured in bankruptcy.