Loans, Leases, and Allowance for Credit Losses (Summary of Accrued Interest Receivables Reversed) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	$ 15	$ 13	$ 17
Recorded investment in TDR loans modified with interest rates below market	264	235
Interest rate reduction
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	4
Maturity or term extension
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	256
Multiple modification types
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	1	74
Commercial
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	10	12	15
Recorded investment in TDR loans modified with interest rates below market	69
Commercial | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	4
Commercial | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	63
Commercial | Multiple modification types
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	0
Commercial | Commercial and industrial
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	47
Commercial | Commercial and industrial | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	0
Commercial | Commercial and industrial | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	46
Commercial | Commercial and industrial | Multiple modification types
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	0
Commercial real estate
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	3	1	2
Recorded investment in TDR loans modified with interest rates below market	192
Commercial real estate | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	0
Commercial real estate | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	192
Commercial real estate | Multiple modification types
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	0
Consumer
Financing Receivable, Past Due [Line Items]
Accrued interest receivable written off	2	$ 0	$ 0
Recorded investment in TDR loans modified with interest rates below market	3
Consumer | Interest rate reduction
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	0
Consumer | Maturity or term extension
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	1
Consumer | Multiple modification types
Financing Receivable, Past Due [Line Items]
Recorded investment in TDR loans modified with interest rates below market	$ 1