Derivative And Credit-Related Financial Instruments (Schedule Of Net Gains Recognized In Income On Customer-Initiated Derivatives) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	$ 22	$ 19	$ 52	$ 39
Customer-initiated and other activities
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	22	19	52	39
Interest rate contracts | Customer-initiated and other activities | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	9	8	24	16
Energy contracts | Customer-initiated and other activities | Other noninterest income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	2	2	6	3
Foreign exchange contracts | Customer-initiated and other activities | Foreign exchange income
Derivative Instruments, Gain (Loss) [Line Items]
Net derivative gain recognized in income	$ 11	$ 9	$ 22	$ 20