Loans, Leases, and Allowance for Credit Losses (Collateral-Dependent Loans) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 37	$ 57
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	27	50
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	10
Owner-occupied | Commercial | Hospital
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 7
Weighted average LTV		17.00%
Construction and land development | Commercial real estate | Lots / Homes
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 2
Weighted average LTV	128.00%
Construction and land development | Commercial real estate | Office Building
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost		$ 22
Weighted average LTV		92.00%
Term | Commercial real estate | Office Building
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 25	$ 28
Weighted average LTV	82.00%	87.00%
Home equity credit line | Consumer | Single Family Residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 7
Weighted average LTV	56.00%
1-4 family residential | Consumer | Single Family Residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost	$ 3
Weighted average LTV	35.00%