Loans and Related Allowance for Credit Losses (Aging Analysis) (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	$ 2,925	$ 2,270
Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	2,116	1,756
30-59 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	15	20
60-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	8	4
90 Days or More Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	7	7
Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	779	483
Total commercial lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	2,721	2,066
Total commercial lending | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	2,057	1,691
Total commercial lending | 30-59 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	9	14
Total commercial lending | 60-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	4
Total commercial lending | 90 Days or More Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis
Total commercial lending | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	651	361
Total commercial lending | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	1,429	1,099
Total commercial lending | Commercial and industrial | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	1,191	828
Total commercial lending | Commercial and industrial | 30-59 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	9	14
Total commercial lending | Commercial and industrial | 60-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	4
Total commercial lending | Commercial and industrial | 90 Days or More Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis
Total commercial lending | Commercial and industrial | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	225	257
Total commercial lending | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	1,290	967
Total commercial lending | Commercial real estate | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	864	863
Total commercial lending | Commercial real estate | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	426	104
Total commercial lending | Equipment lease financing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	2
Total commercial lending | Equipment lease financing | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	2
Total consumer lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	204	204
Total consumer lending | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	59	65
Total consumer lending | 30-59 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	6	6
Total consumer lending | 60-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	4	4
Total consumer lending | 90 Days or More Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	7	7
Total consumer lending | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	128	122
Total consumer lending | Residential real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	98	109
Total consumer lending | Residential real estate | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	5	15
Total consumer lending | Residential real estate | 30-59 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	1	1
Total consumer lending | Residential real estate | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	92	93
Total consumer lending | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	38	31
Total consumer lending | Home equity | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	4	4
Total consumer lending | Home equity | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	34	27
Total consumer lending | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	62	58
Total consumer lending | Credit card | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	45	41
Total consumer lending | Credit card | 30-59 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	5	5
Total consumer lending | Credit card | 60-89 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	4	4
Total consumer lending | Credit card | 90 Days or More Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	7	7
Total consumer lending | Credit card | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	1	1
Total consumer lending | Education
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	5	5
Total consumer lending | Education | Current or Less Than 30 Days Past Due
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	5	5
Total consumer lending | Other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	1	1
Total consumer lending | Other consumer | Nonperforming
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing receivable, aging analysis	$ 1	$ 1