Loans and Related Allowance for Credit Losses (Subsequent Default) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	$ 323	$ 331
Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		47
Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	133	53
Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	96	196
Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	33	16
Payment Deferral and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	40
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	21	19
Total commercial lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	223	272
Total commercial lending | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		46
Total commercial lending | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	133	53
Total commercial lending | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	50	166
Total commercial lending | Payment Deferral and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	40
Total commercial lending | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		7
Total commercial lending | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	107	211
Total commercial lending | Commercial and industrial | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	87	38
Total commercial lending | Commercial and industrial | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	17	166
Total commercial lending | Commercial and industrial | Payment Deferral and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	3
Total commercial lending | Commercial and industrial | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		7
Total commercial lending | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	116	61
Total commercial lending | Commercial real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		46
Total commercial lending | Commercial real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	46	15
Total commercial lending | Commercial real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	33
Total commercial lending | Commercial real estate | Payment Deferral and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	37
Total consumer lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	100	59
Total consumer lending | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		1
Total consumer lending | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default
Total consumer lending | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	46	30
Total consumer lending | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	33	16
Total consumer lending | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	21	12
Total consumer lending | Residential real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	51	31
Total consumer lending | Residential real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default		1
Total consumer lending | Residential real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	43	28
Total consumer lending | Residential real estate | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	8	2
Total consumer lending | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	17	12
Total consumer lending | Home equity | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	3	2
Total consumer lending | Home equity | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	1
Total consumer lending | Home equity | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	13	10
Total consumer lending | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	32	16
Total consumer lending | Credit card | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default	$ 32	16
Total consumer lending | Credit card | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Subsequent default