Credit Quality And Allowance For Credit Losses (Troubled Debt Restructurings Subsequent Default) (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	[1]	Sep. 30, 2022	Sep. 30, 2021	[1]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 39	$ 0		$ 58	$ 1
Business loans | Commercial borrower
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		34	0		52	0
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		27	0		34	0
Business loans | Commercial mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[2]	7	0		15	0
Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[2]				3	0
Retail loans | Home equity | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[3]				1	1
Retail loans | Residential mortgage | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		5	0		5	0
Principal Deferrals
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[4]	34	0		53	0
Principal Deferrals | Business loans | Commercial borrower
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[4]	34	0		52	0
Principal Deferrals | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[4]	27	0		34	0
Principal Deferrals | Business loans | Commercial mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[2],[4]	7	0		15	0
Principal Deferrals | Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[2],[4]				3	0
Principal Deferrals | Retail loans | Home equity | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[3],[4]				1	0
Principal Deferrals | Retail loans | Residential mortgage | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[4]	0	0		0	0
Interest Rate Reductions
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		5	0		5	1
Interest Rate Reductions | Business loans | Commercial borrower
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		0	0		0	0
Interest Rate Reductions | Business loans | Commercial borrower | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		0	0		0	0
Interest Rate Reductions | Business loans | Commercial mortgage | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[2]	0	0		0	0
Interest Rate Reductions | Business loans | Real estate construction | Commercial borrower | Domestic loans | Other business lines
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[2]				0	0
Interest Rate Reductions | Retail loans | Home equity | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[3]				0	1
Interest Rate Reductions | Retail loans | Residential mortgage | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification		$ 5	$ 0		$ 5	$ 0

[1] Under the provisions of the CARES Act, qualifying COVID-19-related modifications, primarily principal deferrals, were not considered TDRs during the nine months ended September 30, 2021.

[2] Primarily loans secured by owner-occupied real estate.

[3] Includes bankruptcy loans for which the court has discharged the borrower's obligation and the borrower has not reaffirmed the debt.

[4] 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.