Loans and Related Allowance for Credit Losses (Nonperforming Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Nonperforming loans, without allowance for credit losses	$ 600	$ 700
Nonperforming loans (a)
Nonperforming loans	2,010	1,985
OREO and foreclosed assets	38	34
Total nonperforming assets	$ 2,048	$ 2,019
Nonperforming loans to total loans	0.62%	0.61%
Nonperforming assets to total loans, OREO and foreclosed assets	0.63%	0.62%
Nonperforming assets to total assets	0.36%	0.36%
Total commercial | Nonperforming loans (a)
Nonperforming loans	$ 891	$ 858
Total consumer | Nonperforming loans (a)
Nonperforming loans	$ 1,119	$ 1,127
Unsecured Consumer Loans | Minimum
Threshold period of financing receivable past due, writeoff	120 days
Unsecured Consumer Loans | Maximum
Threshold period of financing receivable past due, writeoff	180 days