Goodwill And Other Intangible Assets (Amortizing Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Core Deposit Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 167	$ 167
Accumulated amortization	(167)	(166)
Net carrying amount	0	1
Customer Relationships And Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	28	28
Accumulated amortization	(28)	(28)
Net carrying amount	0	0
Finite Lived Intangible Assets Major Class Total [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	195	195
Accumulated amortization	(195)	(194)
Net carrying amount	$ 0	$ 1