Asset Quality (Impaired Loans) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011
Amounts included in the ALLL for the TDR portfolio	$ 570	$ 580
Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	4,025	4,510
Recorded Investment	3,228	3,626
Associated Allowance	857	1,100
Average Recorded Investment	3,378	3,857
Impaired loans without an associated allowance [Member]
Unpaid Principal Balance	1,223	939
Recorded Investment	683	467
Average Recorded Investment	576	517
Total impaired loans [Member]
Unpaid Principal Balance	5,248	5,449
Recorded Investment	3,911	4,093
Associated Allowance	857	1,100
Average Recorded Investment	3,954	4,374
Commercial [Member] | Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	888	1,125
Recorded Investment	598	785
Associated Allowance	163	241
Average Recorded Investment	690	979
Commercial [Member] | Impaired loans without an associated allowance [Member]
Unpaid Principal Balance	458	347
Recorded Investment	209	125
Average Recorded Investment	165	104
Commercial Real Estate [Member] | Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	924	1,452
Recorded Investment	611	1,043
Associated Allowance	167	318
Average Recorded Investment	819	1,247
Commercial Real Estate [Member] | Impaired loans without an associated allowance [Member]
Unpaid Principal Balance	765	592
Recorded Investment	474	342
Average Recorded Investment	411	413
Home Equity [Member] | Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	971	774
Recorded Investment	951	762
Associated Allowance	298	292
Average Recorded Investment	831	702
Residential Real Estate [Member] | Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	964	853
Recorded Investment	790	730
Associated Allowance	174	193
Average Recorded Investment	747	609
Credit Card [Member] | Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	211	258
Recorded Investment	211	258
Associated Allowance	51	53
Average Recorded Investment	233	281
Other Consumer [Member] | Impaired loans with an associated allowance [Member]
Unpaid Principal Balance	67	48
Recorded Investment	67	48
Associated Allowance	4	3
Average Recorded Investment	$ 58	$ 39