Loans and Related Allowance for Credit Losses (Nonperforming Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Nonperforming loans, without allowance for credit losses	$ 900	$ 1,000
Minimum
Threshold period of financing receivable past due, writeoff	120 days
Maximum
Threshold period of financing receivable past due, writeoff	180 days
Nonperforming loans
Nonperforming loans	$ 2,298	2,480
OREO and foreclosed assets	26	26
Total nonperforming assets	$ 2,324	$ 2,506
Nonperforming loans to total loans	0.78%	0.86%
Nonperforming assets to total loans, OREO and foreclosed assets	0.79%	0.87%
Nonperforming assets to total assets	0.43%	0.45%
Total commercial | Nonperforming loans
Nonperforming loans	$ 998	$ 1,168
Total consumer | Nonperforming loans
Nonperforming loans	$ 1,300	$ 1,312