Fair Value (Schedule Of Assets And Liabilities Measured At Fair Value By Class On A Recurring Basis Using Level 3 Inputs) (Details) - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Private Equity Investments [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	$ 79	$ 107	$ 107	$ 102
Securities losses, net	(4)	(2)	(9)	(1)
Other noninterest income (expense)	0	0	0	0
Purchases	2	0	4	4
Other	0	0	(25)	0
Fair value of assets, Ending balance	77	105	77	105
Servicing Contracts [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of assets, Beginning balance	17	17	18	18
Securities losses, net	0	0	0	0
Other noninterest income (expense)	0	2	(1)	1
Purchases	0	0	0	0
Other	0	0	0	0
Fair value of assets, Ending balance	$ 17	$ 19	$ 17	$ 19