Loans and Related Allowance for Credit Losses (Nonperforming Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Financing receivable, nonaccrual, no allowance	$ 500	$ 700
Nonperforming
Total nonperforming loans	2,180	1,985
OREO and Foreclosed Assets	36	34
Total nonperforming assets	$ 2,216	$ 2,019
Nonperforming loans to total loans	0.68%	0.61%
Nonperforming assets to total loans, OREO and foreclosed assets	0.69%	0.62%
Nonperforming assets to total assets	0.39%	0.36%
Minimum
Threshold period of financing receivable past due, writeoff	120 days
Maximum
Threshold period of financing receivable past due, writeoff	180 days
Commercial | Nonperforming
Total nonperforming loans	$ 1,307	$ 858
Consumer | Nonperforming
Total nonperforming loans	$ 873	$ 1,127