Credit Quality And Allowance For Credit Losses (Troubled Debt Restructurings Subsequent Default) (Details) - Principal Deferrals - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021	[2]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[1]	$ 23	$ 0
Business loans | Commercial borrower | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[1]	21	0
Retail loans | Home equity | Home equity | Domestic loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	[1],[3]	$ 2	$ 0

[1] 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.

[2] Under the provisions of the CARES Act, qualifying COVID-19-related modifications, primarily principal deferrals, were not considered TDRs during the three months ended March 31, 2021.

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