Investment Securities (Details 8) (USD $) In Millions, unless otherwise specified	Sep. 30, 2011 Basis_Points Multiple Year	Dec. 31, 2010
Available-for-sale securities
Available-for-sale securities, total, amortized cost	$ 51,492	$ 51,855
Available-for-sale securities, total, fair value	52,109
Available-for-sale securities, total, weighted average maturity in years	5.3
Available-for-sale securities, total, weighted average yield	3.25%
Held-to-maturity
Held-to-maturity securities, total, amortized cost	16,269	1,469
Held-to-maturity securities, total, fair value	16,613	1,419
Held-to-maturity securities, total, weighted average maturity in years	4.0
Held-to-maturity securities, total, weighted average yield	2.20%
Investment securities
Total investment securities amortized cost	67,761	53,324
Total investment securities, percentage	100.00%	100.00%
Mortgage Backed Securities [Member]
Held-to-maturity
Held-to-maturity securities, maturing in one year, amortized cost	200
Held-to-maturity securities, maturing after one year through five years, amortized cost	10,884
Held-to-maturity securities, maturing after five years through ten years, amortized cost	1,801
Held-to-maturity securities, maturing after ten years, amortized cost	522
Held-to-maturity securities, total, amortized cost	13,407
Held-to-maturity securities, maturing in one year, fair value	198
Held-to-maturity securities, maturing after one year through five years, fair value	11,168
Held-to-maturity securities, maturing after five years through ten years, fair value	1,843
Held-to-maturity securities, maturing after ten years, fair value	530
Held-to-maturity securities, total, fair value	13,739
Held-to-maturity securities, maturing in one year of less, weighted average maturity in years	0.7
Held-to-maturity securities, maturing after one year through five years, weighted average maturity in years	3.6
Held-to-maturity securities, maturing after five years through ten years, weighted average maturity in years	5.5
Held-to-maturity securities, maturing after ten years, weighted average maturity in years	11.9
Held-to-maturity securities, total, weighted average maturity in years	4.2
Held-to-maturity securities, maturing in one year of less, weighted average yield	1.48%
Held-to-maturity securities, maturing after one year through five years, weighted average yield	2.57%
Held-to-maturity securities, maturing after five years through ten years, weighted average yield	2.07%
Held-to-maturity securities, maturing after ten years, weighted average yield	1.42%
Held-to-maturity securities, total, weighted average yield	2.44%
Investment securities
Total investment securities amortized cost	54,383	40,654
Total investment securities, percentage	80.20%	76.20%
Mortgage Backed Securities [Member]
Available-for-sale securities
Available-for-sale, securities maturing within one year, amortized cost	679
Available-for-sale, securities maturing after one through five years, amortized cost	30,646
Available-for-sale, securities maturing after five through ten years, amortized cost	7,863
Available-for-sale, securities maturing after ten years, amortized cost	1,788
Available-for-sale securities, total, amortized cost	40,976
Available-for-sale securities, maturing in one year or less, fair value	680
Available-for-sale securities, maturing after one year through five years, fair value	31,508
Available-for-sale securities, maturing after five years through ten years, fair value	7,730
Available-for-sale securities, maturing after ten years, fair value	1,728
Available-for-sale securities, total, fair value	41,646
Available-for-sale securities, maturing in one year or less, weighted average maturity in years	0.6
Available-for-sale securities, maturing after one year through five years, weighted average maturity in years	3.4
Available-for-sale securities, maturing after five years through ten years, weighted average maturity in years	6.6
Available-for-sale securities, maturing after ten years, weighted average maturity in years	12.3
Available-for-sale securities, total, weighted average maturity in years	4.4
Available-for-sale securities, maturing in one year of less, weighted average yield	2.53%
Available-for-sale securities, maturing after one year through five years, weighted average yield	2.92%
Available-for-sale securities, maturing after five years through ten years, weighted average yield	2.02%
Available-for-sale securities, maturing after ten years, weighted average yield	1.69%
Available-for-sale securities, total, weighted average yield	2.69%
U.S. Treasury and agency [Member]
Held-to-maturity
Held-to-maturity securities, maturing after one year through five years, amortized cost	2,501
Held-to-maturity securities, maturing after ten years, amortized cost	122
Held-to-maturity securities, total, amortized cost	2,623	165
Held-to-maturity securities, maturing after one year through five years, fair value	2,537
Held-to-maturity securities, maturing after ten years, fair value	122
Held-to-maturity securities, total, fair value	2,659
Held-to-maturity securities, maturing after one year through five years, weighted average maturity in years	2.4
Held-to-maturity securities, maturing after ten years, weighted average maturity in years	12.0
Held-to-maturity securities, total, weighted average maturity in years	2.9
Held-to-maturity securities, maturing after one year through five years, weighted average yield	0.99%
Held-to-maturity securities, maturing after ten years, weighted average yield	1.74%
Held-to-maturity securities, total, weighted average yield	1.02%
Investment securities
Total investment securities amortized cost	4,100	2,724
Total investment securities, percentage	6.10%	5.10%
U.S. Treasury and agency [Member]
Available-for-sale securities
Available-for-sale, securities maturing within one year, amortized cost	852
Available-for-sale, securities maturing after one through five years, amortized cost	556
Available-for-sale, securities maturing after five through ten years, amortized cost	49
Available-for-sale, securities maturing after ten years, amortized cost	20
Available-for-sale securities, total, amortized cost	1,477	2,559
Available-for-sale securities, maturing in one year or less, fair value	853
Available-for-sale securities, maturing after one year through five years, fair value	562
Available-for-sale securities, maturing after five years through ten years, fair value	53
Available-for-sale securities, maturing after ten years, fair value	21
Available-for-sale securities, total, fair value	1,489
Available-for-sale securities, maturing in one year or less, weighted average maturity in years	0.3
Available-for-sale securities, maturing after one year through five years, weighted average maturity in years	2.2
Available-for-sale securities, maturing after five years through ten years, weighted average maturity in years	8.5
Available-for-sale securities, maturing after ten years, weighted average maturity in years	11.8
Available-for-sale securities, total, weighted average maturity in years	1.4
Available-for-sale securities, maturing in one year of less, weighted average yield	1.73%
Available-for-sale securities, maturing after one year through five years, weighted average yield	0.92%
Available-for-sale securities, maturing after five years through ten years, weighted average yield	4.24%
Available-for-sale securities, maturing after ten years, weighted average yield	3.42%
Available-for-sale securities, total, weighted average yield	1.53%
Obligations Of State and Political Subdivisions [Member]
Held-to-maturity
Held-to-maturity securities, maturing after one year through five years, amortized cost	5
Held-to-maturity securities, maturing after five years through ten years, amortized cost	4
Held-to-maturity securities, maturing after ten years, amortized cost	15
Held-to-maturity securities, total, amortized cost	24	27
Held-to-maturity securities, maturing after one year through five years, fair value	6
Held-to-maturity securities, maturing after five years through ten years, fair value	4
Held-to-maturity securities, maturing after ten years, fair value	14
Held-to-maturity securities, total, fair value	24
Held-to-maturity securities, maturing in one year of less, weighted average maturity in years	0.5
Held-to-maturity securities, maturing after one year through five years, weighted average maturity in years	3.3
Held-to-maturity securities, maturing after five years through ten years, weighted average maturity in years	6.0
Held-to-maturity securities, maturing after ten years, weighted average maturity in years	15.4
Held-to-maturity securities, total, weighted average maturity in years	11.2
Held-to-maturity securities, maturing in one year of less, weighted average yield	7.62%
Held-to-maturity securities, maturing after one year through five years, weighted average yield	8.38%
Held-to-maturity securities, maturing after five years through ten years, weighted average yield	5.38%
Held-to-maturity securities, maturing after ten years, weighted average yield	5.53%
Held-to-maturity securities, total, weighted average yield	6.17%
Investment securities
Total investment securities amortized cost	6,433	6,862
Total investment securities, percentage	9.50%	12.90%
Obligations Of State and Political Subdivisions [Member]
Available-for-sale securities
Available-for-sale, securities maturing within one year, amortized cost	16
Available-for-sale, securities maturing after one through five years, amortized cost	3,083
Available-for-sale, securities maturing after five through ten years, amortized cost	2,888
Available-for-sale, securities maturing after ten years, amortized cost	422
Available-for-sale securities, total, amortized cost	6,409	6,835
Available-for-sale securities, maturing in one year or less, fair value	16
Available-for-sale securities, maturing after one year through five years, fair value	3,145
Available-for-sale securities, maturing after five years through ten years, fair value	2,946
Available-for-sale securities, maturing after ten years, fair value	392
Available-for-sale securities, total, fair value	6,499
Available-for-sale securities, maturing in one year or less, weighted average maturity in years	0.4
Available-for-sale securities, maturing after one year through five years, weighted average maturity in years	4.1
Available-for-sale securities, maturing after five years through ten years, weighted average maturity in years	5.7
Available-for-sale securities, maturing after ten years, weighted average maturity in years	20.4
Available-for-sale securities, total, weighted average maturity in years	5.9
Available-for-sale securities, maturing in one year of less, weighted average yield	6.08%
Available-for-sale securities, maturing after one year through five years, weighted average yield	6.59%
Available-for-sale securities, maturing after five years through ten years, weighted average yield	6.79%
Available-for-sale securities, maturing after ten years, weighted average yield	7.19%
Available-for-sale securities, total, weighted average yield	6.72%
Asset backed Securities [Member]
Held-to-maturity
Held-to-maturity securities, maturing in one year, amortized cost	2
Held-to-maturity securities, maturing after one year through five years, amortized cost	44
Held-to-maturity securities, maturing after five years through ten years, amortized cost	14
Held-to-maturity securities, maturing after ten years, amortized cost	24
Held-to-maturity securities, total, amortized cost	84
Held-to-maturity securities, maturing in one year, fair value	2
Held-to-maturity securities, maturing after one year through five years, fair value	44
Held-to-maturity securities, maturing after five years through ten years, fair value	17
Held-to-maturity securities, maturing after ten years, fair value	25
Held-to-maturity securities, total, fair value	88
Held-to-maturity securities, maturing in one year of less, weighted average maturity in years	0.3
Held-to-maturity securities, maturing after one year through five years, weighted average maturity in years	2.9
Held-to-maturity securities, maturing after five years through ten years, weighted average maturity in years	6.3
Held-to-maturity securities, maturing after ten years, weighted average maturity in years	23.0
Held-to-maturity securities, total, weighted average maturity in years	9.1
Held-to-maturity securities, maturing in one year of less, weighted average yield	1.01%
Held-to-maturity securities, maturing after one year through five years, weighted average yield	0.95%
Held-to-maturity securities, maturing after five years through ten years, weighted average yield	0.87%
Held-to-maturity securities, maturing after ten years, weighted average yield	0.82%
Held-to-maturity securities, total, weighted average yield	0.90%
Investment securities
Total investment securities amortized cost	966	1,197
Total investment securities, percentage	1.40%	2.30%
Asset backed Securities [Member]
Available-for-sale securities
Available-for-sale, securities maturing within one year, amortized cost	6
Available-for-sale, securities maturing after one through five years, amortized cost	179
Available-for-sale, securities maturing after five through ten years, amortized cost	689
Available-for-sale, securities maturing after ten years, amortized cost	8
Available-for-sale securities, total, amortized cost	882
Available-for-sale securities, maturing in one year or less, fair value	15
Available-for-sale securities, maturing after one year through five years, fair value	185
Available-for-sale securities, maturing after five years through ten years, fair value	695
Available-for-sale securities, maturing after ten years, fair value	9
Available-for-sale securities, total, fair value	904
Available-for-sale securities, maturing in one year or less, weighted average maturity in years	0.5
Available-for-sale securities, maturing after one year through five years, weighted average maturity in years	3.5
Available-for-sale securities, maturing after five years through ten years, weighted average maturity in years	8.0
Available-for-sale securities, maturing after ten years, weighted average maturity in years	15.9
Available-for-sale securities, total, weighted average maturity in years	7.1
Available-for-sale securities, maturing in one year of less, weighted average yield	13.56%
Available-for-sale securities, maturing after one year through five years, weighted average yield	13.01%
Available-for-sale securities, maturing after five years through ten years, weighted average yield	2.81%
Available-for-sale securities, maturing after ten years, weighted average yield	7.80%
Available-for-sale securities, total, weighted average yield	5.01%
Other debt securities and obligations of foreign governments [Member]
Held-to-maturity
Held-to-maturity securities, maturing in one year, amortized cost	1
Held-to-maturity securities, maturing after one year through five years, amortized cost	12
Held-to-maturity securities, maturing after five years through ten years, amortized cost	118
Held-to-maturity securities, total, amortized cost	131
Held-to-maturity securities, maturing in one year, fair value	1
Held-to-maturity securities, maturing after one year through five years, fair value	10
Held-to-maturity securities, maturing after five years through ten years, fair value	92
Held-to-maturity securities, total, fair value	103
Held-to-maturity securities, maturing in one year of less, weighted average maturity in years	0.5
Held-to-maturity securities, maturing after one year through five years, weighted average maturity in years	2.0
Held-to-maturity securities, maturing after five years through ten years, weighted average maturity in years	7.0
Held-to-maturity securities, total, weighted average maturity in years	6.5
Held-to-maturity securities, maturing in one year of less, weighted average yield	0.84%
Held-to-maturity securities, maturing after one year through five years, weighted average yield	1.29%
Held-to-maturity securities, maturing after five years through ten years, weighted average yield	1.17%
Held-to-maturity securities, total, weighted average yield	1.18%
Other debt securities and obligations of foreign governments [Member]
Available-for-sale securities
Available-for-sale, securities maturing within one year, amortized cost	122
Available-for-sale, securities maturing after one through five years, amortized cost	0
Available-for-sale, securities maturing after five through ten years, amortized cost	31
Available-for-sale, securities maturing after ten years, amortized cost	1,282
Available-for-sale securities, total, amortized cost	1,435
Available-for-sale securities, maturing in one year or less, fair value	112
Available-for-sale securities, maturing after one year through five years, fair value	0
Available-for-sale securities, maturing after five years through ten years, fair value	28
Available-for-sale securities, maturing after ten years, fair value	1,091
Available-for-sale securities, total, fair value	1,231
Available-for-sale securities, maturing in one year or less, weighted average maturity in years	0.4
Available-for-sale securities, maturing after one year through five years, weighted average maturity in years	0.0
Available-for-sale securities, maturing after five years through ten years, weighted average maturity in years	6.0
Available-for-sale securities, maturing after ten years, weighted average maturity in years	30.3
Available-for-sale securities, total, weighted average maturity in years	27.2
Available-for-sale securities, maturing in one year of less, weighted average yield	6.24%
Available-for-sale securities, maturing after one year through five years, weighted average yield	0.00%
Available-for-sale securities, maturing after five years through ten years, weighted average yield	6.33%
Available-for-sale securities, maturing after ten years, weighted average yield	4.07%
Available-for-sale securities, total, weighted average yield	4.30%
Other Investments [Member]
Available-for-sale securities
Available-for-sale securities, total, amortized cost	313
Available-for-sale securities, total, fair value	340
Available-for-sale securities, total, weighted average maturity in years	17.3
Available-for-sale securities, total, weighted average yield	3.99%
Other Debt Securities and Investments [Member]
Investment securities
Total investment securities amortized cost	$ 1,879	$ 1,887
Total investment securities, percentage	2.80%	3.50%