Loans, Leases, and Allowance for Credit Losses (Summary of Accrued Interest Receivables Reversed) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	$ 5	$ 3
Amortized cost basis	123	97
Interest rate reduction
Financing Receivable, Past Due [Line Items]
Amortized cost basis	0	4
Maturity or term extension
Financing Receivable, Past Due [Line Items]
Amortized cost basis	114	92
Multiple modification types
Financing Receivable, Past Due [Line Items]
Amortized cost basis	7	1
Commercial
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	3	2
Amortized cost basis	33	46
Commercial | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Amortized cost basis	0	4
Commercial | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Amortized cost basis	29	42
Commercial | Multiple modification types
Financing Receivable, Past Due [Line Items]
Amortized cost basis	4	0
Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Amortized cost basis	30	36
Commercial | Commercial and industrial | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Amortized cost basis	0	0
Commercial | Commercial and industrial | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Amortized cost basis	26	36
Commercial | Commercial and industrial | Multiple modification types
Financing Receivable, Past Due [Line Items]
Amortized cost basis	4	0
Commercial real estate
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	1	1
Amortized cost basis	84	49
Commercial real estate | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Amortized cost basis	0	0
Commercial real estate | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Amortized cost basis	84	49
Commercial real estate | Multiple modification types
Financing Receivable, Past Due [Line Items]
Amortized cost basis	0	0
Consumer
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	1	0
Amortized cost basis	6	2
Consumer | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Amortized cost basis	0	0
Consumer | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Amortized cost basis	1	1
Consumer | Multiple modification types
Financing Receivable, Past Due [Line Items]
Amortized cost basis	$ 3	$ 1