Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Investment securities, Balance at beginning of period, net of tax	$ (68)	$ 150
Investment securities, Net unrealized holding gains (losses) arising during the period	85	(270)
Investment securities, Provision (benefit) for income taxes	30	(100)
Investment securities, Net unrealized holding gains (losses) arising during period, net of tax	55	(170)
Investment securities, Net realized gains included in net securities gains	1	1
Investment securities, Provision for income taxes	0	0
Investment securities, Reclassification adjustment for net securities gains included in net income, net of tax	1	1
Investment securities, Change in net unrealized gains (losses) on investment securities available-for-sale, net of tax	54	(171)
Investment securities, Balance at end of period, net of tax	(14)	(21)
Benefit plans, Balance at beginning of period, net of tax	(323)	(563)
Amortization of actuarial net loss	30	65
Amortization of prior service cost	1	2
Benefit plans, Amounts recognized in salaries and benefits expense	31	67
Benefit plans, Provision for income taxes	11	24
Benefit plans, Change in defined benefit pension and other postretirement plans adjustment, net of tax	20	43
Benefit plans, Balance at end of period, net of tax	(303)	(520)
Total accumulated other comprehensive loss at end of period, net of tax	$ (317)	$ (541)	$ (391)