Loans and Related Allowance for Credit Losses (Modified, Amortized Cost Basis) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 2,925	$ 2,270
% of Loan Class	0.92%	0.71%
Unfunded lending related commitments	$ 900	$ 400
Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	14	62
Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	1,967	1,506
Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	225	170
Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	70	67
Interest Rate Reduction and Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	15	14
Interest Rate Reduction and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	117	23
Payment Delay and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	386	173
Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	131	255
Commercial and industrial | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	140	45
Commercial and industrial | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	1,260	857
Commercial and industrial | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	203	235
Commercial real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		47
Commercial real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	1,196	833
Commercial real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	326	17
Equipment lease financing | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	2
Residential real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	6	7
Residential real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	7	6
Residential real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	84	95
Home equity | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		1
Home equity | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	13	10
Education | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	5	5
Total commercial lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 2,721	$ 2,066
% of Loan Class	1.26%	0.94%
Total commercial lending | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 14	$ 60
Total commercial lending | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	1,961	1,499
Total commercial lending | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	128	65
Total commercial lending | Interest Rate Reduction and Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	15	14
Total commercial lending | Interest Rate Reduction and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	111	18
Total commercial lending | Payment Delay and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	386	173
Total commercial lending | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	106	237
Total commercial lending | Commercial and industrial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1,429	$ 1,099
% of Loan Class	0.81%	0.62%
Total commercial lending | Commercial and industrial | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 14	$ 13
Total commercial lending | Commercial and industrial | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	995	683
Total commercial lending | Commercial and industrial | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	34	65
Total commercial lending | Commercial and industrial | Interest Rate Reduction and Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	15	14
Total commercial lending | Commercial and industrial | Interest Rate Reduction and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	111	18
Total commercial lending | Commercial and industrial | Payment Delay and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	154	156
Total commercial lending | Commercial and industrial | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	106	150
Total commercial lending | Commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1,290	$ 967
% of Loan Class	3.84%	2.73%
Total commercial lending | Commercial real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		$ 47
Total commercial lending | Commercial real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 964	816
Total commercial lending | Commercial real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	94
Total commercial lending | Commercial real estate | Payment Delay and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	232	17
Total commercial lending | Commercial real estate | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		87
Total commercial lending | Equipment lease financing
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 2
% of Loan Class	0.03%
Total commercial lending | Equipment lease financing | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 2
Total consumer lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 204	$ 204
% of Loan Class	0.20%	0.20%
Total consumer lending | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		$ 2
Total consumer lending | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 6	7
Total consumer lending | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	97	105
Total consumer lending | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	70	67
Total consumer lending | Interest Rate Reduction and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	6	5
Total consumer lending | Payment Delay and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified
Total consumer lending | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	25	18
Total consumer lending | Residential real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 98	$ 109
% of Loan Class	0.21%	0.23%
Total consumer lending | Residential real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		$ 2
Total consumer lending | Residential real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1	1
Total consumer lending | Residential real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	84	95
Total consumer lending | Residential real estate | Interest Rate Reduction and Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	6	5
Total consumer lending | Residential real estate | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	7	6
Total consumer lending | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 38	$ 31
% of Loan Class	0.15%	0.12%
Total consumer lending | Home equity | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		$ 1
Total consumer lending | Home equity | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	13	10
Total consumer lending | Home equity | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	7	8
Total consumer lending | Home equity | Other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	18	12
Total consumer lending | Credit card
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 62	$ 58
% of Loan Class	0.90%	0.81%
Total consumer lending | Credit card | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified
Total consumer lending | Credit card | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	62	$ 58
Total consumer lending | Education
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 5	$ 5
% of Loan Class	0.31%	0.26%
Total consumer lending | Education | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 5	$ 5
Total consumer lending | Other consumer
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1	$ 1
% of Loan Class	0.02%	0.02%
Total consumer lending | Other consumer | Repayment Plan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1	$ 1