Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Investment securities, Balance at beginning of period, net of tax	$ 37	$ (68)
Investment securities, Net unrealized holding (losses) gains arising during the period	(17)	116
Investment securities, (Benefit) Provision for income taxes	(6)	41
Investment securities, Net unrealized holding (losses) gains arising during period, net of tax	(11)	75
Investment securities, Net realized (losses) gains included in net securities (losses) gains	(2)	1
Investment securities, Benefit for income taxes	(1)	0
Investment securities, Reclassification adjustment for net securities (losses) gains included in net income, net of tax	(1)	1
Investment securities, Net losses realized as a yield adjustment in interest on investment securities	(4)	0
Investment securities, Benefit for income taxes	(1)	0
Investment Securities, Reclassification adjustment for net losses realized as a yield adjustment included in net income, net of tax	(3)	0
Investment securities, Change in net unrealized (losses) gains on investment securities available-for-sale, net of tax	(7)	74
Investment securities, Balance at end of period, net of tax	30	6
Benefit plans, Balance at beginning of period, net of tax	(449)	(323)
Amortization of actuarial net loss recognized in salaries and benefits expense	35	18
Amortization of prior service cost	0	1
Benefit plans, Amounts recognized in salaries and benefits expense	35	19
Benefit plans, Provision for income taxes	12	6
Benefit plans, Change in defined benefit pension and other postretirement plans adjustment, net of tax	23	13
Benefit plans, Balance at end of period, net of tax	(426)	(310)
Total accumulated other comprehensive loss at end of period, net of tax	$ (396)	$ (304)	$ (412)