Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Change in defined benefit pension and other postretirement plans adjustment before income taxes	$ (127)
Total accumulated other comprehensive loss at end of period, net of tax	(356)	(389)	(336)
Accumulated Net Unrealized Gains On Investment Securities Available-For-Sale [Member]
Balance at beginning of period, net of tax	14	11	131
Net unrealized holding gains arising during the period	202	12	56
Less: Reclassification adjustment for net gains included in net income	21	8	245
Change in net unrealized gains before income taxes	181	4	(189)
Less: Provision for income taxes	66	1	(69)
Change in net unrealized gains on investment securities available-for-sale, net of tax	115	3	(120)
Balance at end of period, net of tax	129	14	11
Accumulated Net Gains On Cash Flow Hedges [Member]
Balance at beginning of period, net of tax	2	18	30
Net cash flow hedge gains (losses) arising during the period	(2)	2	15
Less: Reclassification adjustment for net gains included in net income	1	28	34
Change in net cash flow hedge gains (losses) before income taxes	(3)	(26)	(19)
Less: Provision (benefit) for income taxes	(1)	(10)	(7)
Change in net cash flow hedge gains, net of tax	(2)	(16)	(12)
Balance at end of period, net of tax	0	2	18
Accumulated Defined Benefit Pension And Other Postretirement Plans Adjustment [Member]
Balance at beginning of period, net of tax	(405)	(365)	(470)
Net defined benefit pension and other postretirement adjustment arising during the period	(176)	(100)	112
Less: Adjustment for amounts recognized as components of net periodic benefit cost during the period	(49)	(39)	(53)
Change in defined benefit pension and other postretirement plans adjustment before income taxes	(127)	(61)	165
Less: Provision for income taxes	(47)	(21)	60
Change in defined benefit pension and other postretirement plans adjustment, net of tax	(80)	(40)	105
Balance at end of period, net of tax	$ (485)	$ (405)	$ (365)