Loans and Related Allowance for Credit Losses (Financial Effect of Loan Modification) (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
Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	1,967	1,506
Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	14	62
Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	225	170
Commercial and industrial | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1,260	$ 857
Weighted average increase from modification	16 months	12 months
Commercial and industrial | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 140	$ 45
Weighted average interest rate reduction	1.42%	2.70%
Commercial and industrial | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 203	$ 235
Weighted average payment deferral term	8 months	3 months
Commercial real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 1,196	$ 833
Weighted average increase from modification	17 months	14 months
Commercial real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		$ 47
Weighted average interest rate reduction		4.54%
Commercial real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 326	$ 17
Weighted average payment deferral term	8 months	5 months
Equipment lease financing | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 2
Weighted average increase from modification	43 months
Residential real estate | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 7	$ 6
Weighted average increase from modification	94 months	80 months
Residential real estate | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 6	$ 7
Weighted average interest rate reduction	2.00%	1.34%
Residential real estate | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 84	$ 95
Weighted average payment deferral term	9 months	9 months
Education | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 5	$ 5
Weighted average increase from modification	13 months	20 months
Home equity | Term Extension
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified		$ 1
Weighted average increase from modification		232 months
Home equity | Payment Delay
Financing Receivable, Troubled Debt Restructuring [Line Items]
Amortized cost basis, modified	$ 13	$ 10
Weighted average payment deferral term	4 months	4 months