Investment Securities (Contractual Maturity of Debt Securities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2011
Available-for-sale Securities, Fair value	$ 49,361
Weighted-average yield, GAAP basis, available for sale securities	3.75%
Held-to-maturity Securities, Fair Value	9,910
Weighted-average yield, GAAP basis, held to maturity securities	4.11%
US Treasury and Government Agencies Securities [Member]
After 1 year through 5 years	1,694
After 5 years through 10 years	1,830
After 10 years	430
Total	3,954
Residential Mortgage-backed Agency [Member]
After 1 year through 5 years	7
After 5 years through 10 years	1,023
After 10 years	24,096
Total	25,126
Residential Mortgage-backed Non-agency [Member]
After 5 years through 10 years	30
After 10 years	7,202
Total	7,232
Commercial Mortgage-backed Agency [Member]
After 1 year through 5 years	723
After 5 years through 10 years	479
After 10 years	74
Total	1,276
Commercial Mortgage-backed Non-agency [Member]
1 year or less	137
After 1 year through 5 years	47
After 5 years through 10 years	58
After 10 years	3,785
Total	4,027
Commercial Mortgage-backed Non-agency [Member]
1 year or less	33
After 1 year through 5 years	146
After 5 years through 10 years	49
After 10 years	2,266
Total	2,494
Asset backed [Member]
1 year or less	30
After 1 year through 5 years	1,517
After 5 years through 10 years	136
After 10 years	380
Total	2,063
Asset backed [Member]
1 year or less	68
After 1 year through 5 years	795
After 5 years through 10 years	451
After 10 years	2,525
Total	3,839
State and Municipal [Member]
1 year or less	37
After 1 year through 5 years	121
After 5 years through 10 years	312
After 10 years	1,811
Total	2,281
State and Municipal [Member]
After 5 years through 10 years	5
After 10 years	3
Total	8
Other Debt Securities [Member]
After 1 year through 5 years	1
After 5 years through 10 years	365
Total	366
Other Debt Securities [Member]
1 year or less	156
After 1 year through 5 years	2,162
After 5 years through 10 years	504
After 10 years	521
Total	3,343
Total Securities Available for Sale [Member]
1 year or less	294
After 1 year through 5 years	5,648
After 5 years through 10 years	4,678
After 10 years	38,925
Total	49,545
Total securities held to maturity [Member]
1 year or less	167
After 1 year through 5 years	1,565
After 5 years through 10 years	938
After 10 years	7,077
Total	9,747
Commercial Mortgage Backed Agency Htm [Member]
After 5 years through 10 years	374
After 10 years	134
Total	508
Residential Mortgage Backed Agency Htm [Member]
After 10 years	2,775
Total	2,775
One Year or Less [Member]
Available-for-sale Securities, Fair value	298
Weighted-average yield, GAAP basis, available for sale securities	3.03%
Held-to-maturity Securities, Fair Value	171
Weighted-average yield, GAAP basis, held to maturity securities	4.49%
After One Year Through Five Years [Member]
Available-for-sale Securities, Fair value	5,816
Weighted-average yield, GAAP basis, available for sale securities	2.67%
Held-to-maturity Securities, Fair Value	1,594
Weighted-average yield, GAAP basis, held to maturity securities	2.02%
After Five Years Through Ten Years [Member]
Available-for-sale Securities, Fair value	4,854
Weighted-average yield, GAAP basis, available for sale securities	3.48%
Held-to-maturity Securities, Fair Value	936
Weighted-average yield, GAAP basis, held to maturity securities	3.28%
After Ten Years [Member]
Available-for-sale Securities, Fair value	38,393
Weighted-average yield, GAAP basis, available for sale securities	3.95%
Held-to-maturity Securities, Fair Value	$ 7,209
Weighted-average yield, GAAP basis, held to maturity securities	4.68%