Guarantees, Commitments And Contingencies (Schedule Of Guarantees Issued) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Guarantor Obligations [Line Items]
Unused Commitments to Extend Credit	$ 21,454	$ 19,583
Commercial letters of credit	18	31
Total Unfunded Lending Commitments	22,326	20,531
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Letters Of Credit Standby	655	721
Performance Guarantee [Member]
Guarantor Obligations [Line Items]
Letters Of Credit Standby	$ 199	$ 196