Guarantees, Commitments And Contingencies (Schedule Of Guarantees Issued) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	$ 23,099	$ 21,454
Commercial letters of credit	5	18
Total Unfunded Lending Commitments	23,927	22,326
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Letters Of Credit Standby	631	655
Performance Guarantee [Member]
Guarantor Obligations [Line Items]
Letters Of Credit Standby	$ 192	$ 199