Loans, Leases, and Allowance for Credit Losses (Collateral-Dependent Loans) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 57	$ 7
Owner-occupied | Commercial | Hospital
Financing Receivable, Allowance for Credit Losses [Line Items]
Weighted Average LTV	17.00%
Owner-occupied | Commercial | Land, Warehouse
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 7	$ 2
Weighted Average LTV		29.00%
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]
Weighted Average LTV	87.00%
Term | Commercial real estate | Multi-family
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost	$ 28	$ 1
Weighted Average LTV		55.00%
Home equity credit line | Consumer | Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost		$ 1
Weighted Average LTV		13.00%
1-4 family residential | Consumer | Single family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized Cost		$ 3
Weighted Average LTV		41.00%