Derivative And Credit-Related Financial Instruments (Schedule Of Financial Instruments With Off-Balance Sheet Credit Risk) (Details) - Maximum - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss	$ 29,441	$ 26,740
Commercial And Other | Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss	25,945	23,443
Bankcard, Revolving Check Credit And Home Equity Loan Commitments | Unused Commitments to Extend Credit
Loss contingency, estimate of possible loss	3,496	3,297
Standby Letters Of Credit
Loss contingency, estimate of possible loss	3,350	3,273
Commercial Letters Of Credit
Loss contingency, estimate of possible loss	$ 60	$ 30