Investment Securities (Schedule Of Contractual Maturities Of Debt Securities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Available for sale, Under 1 Year	$ 8,805
Available for sale, 1 to 5 Years	20,813
Available for sale, 6 to 10 Years	34,264
Available for sale, Over 10 Years	35,192
Held to maturity, Under 1 Year	1,757
Held to maturity, 1 to 5 Years	2,031
Held to maturity, 6 to 10 Years	851
Held to maturity, Over 10 Years	4,682
Student Loans [Member]
Available for sale, Under 1 Year	155
Available for sale, 1 to 5 Years	3,331
Available for sale, 6 to 10 Years	8,490
Available for sale, Over 10 Years	4,569
Credit Cards [Member]
Available for sale, Under 1 Year	1,893
Available for sale, 1 to 5 Years	5,893
Available for sale, 6 to 10 Years	2,701
Sub-Prime [Member]
Available for sale, Under 1 Year	581
Available for sale, 1 to 5 Years	82
Available for sale, 6 to 10 Years	17
Available for sale, Over 10 Years	724
Other Asset-Backed Securities [Member]
Available for sale, Under 1 Year	119
Available for sale, 1 to 5 Years	1,602
Available for sale, 6 to 10 Years	1,198
Available for sale, Over 10 Years	546
Asset-Backed Securities [Member]
Available for sale, Under 1 Year	2,748
Available for sale, 1 to 5 Years	10,908
Available for sale, 6 to 10 Years	12,406
Available for sale, Over 10 Years	5,839
State And Political Subdivisions [Member]
Available for sale, Under 1 Year	471
Available for sale, 1 to 5 Years	2,326
Available for sale, 6 to 10 Years	3,328
Available for sale, Over 10 Years	922
Held to maturity, Under 1 Year	56
Held to maturity, 1 to 5 Years	49
Held to maturity, 6 to 10 Years	2
Collateralized Mortgage Obligations [Member]
Available for sale, Under 1 Year	81
Available for sale, 1 to 5 Years	1,163
Available for sale, 6 to 10 Years	1,209
Available for sale, Over 10 Years	1,527
Held to maturity, Under 1 Year	394
Held to maturity, 1 to 5 Years	1,350
Held to maturity, 6 to 10 Years	530
Held to maturity, Over 10 Years	1,060
Other U.S. Debt Securities [Member]
Available for sale, Under 1 Year	289
Available for sale, 1 to 5 Years	1,391
Available for sale, 6 to 10 Years	1,899
Available for sale, Over 10 Years	36
U.S. Treasury And Federal Agencies [Member] | Direct Obligations [Member]
Available for sale, Under 1 Year	1,200
Available for sale, 1 to 5 Years	38
Available for sale, 6 to 10 Years	822
Available for sale, Over 10 Years	776
U.S. Treasury And Federal Agencies [Member] | Mortgage-Backed Securities [Member]
Available for sale, Under 1 Year	5
Available for sale, 1 to 5 Years	755
Available for sale, 6 to 10 Years	10,871
Available for sale, Over 10 Years	18,390
Held to maturity, 1 to 5 Years	19
Held to maturity, 6 to 10 Years	102
Held to maturity, Over 10 Years	144
U.S. Treasury And Federal Agencies [Member] | Asset-Backed Securities [Member]
Held to maturity, Over 10 Years	31
Non-U.S. Debt Securities [Member]
Available for sale, Under 1 Year	4,011
Available for sale, 1 to 5 Years	4,232
Available for sale, 6 to 10 Years	3,729
Available for sale, Over 10 Years	7,702
Held to maturity, Under 1 Year	1,307
Held to maturity, 1 to 5 Years	613
Held to maturity, 6 to 10 Years	217
Held to maturity, Over 10 Years	3,447
Non-U.S. Debt Securities [Member] | Mortgage-Backed Securities [Member]
Available for sale, Under 1 Year	474
Available for sale, 1 to 5 Years	2,358
Available for sale, 6 to 10 Years	987
Available for sale, Over 10 Years	7,056
Held to maturity, Under 1 Year	1,304
Held to maturity, 1 to 5 Years	254
Held to maturity, Over 10 Years	3,415
Non-U.S. Debt Securities [Member] | Asset-Backed Securities [Member]
Available for sale, Under 1 Year	230
Available for sale, 1 to 5 Years	916
Available for sale, 6 to 10 Years	2,511
Available for sale, Over 10 Years	646
Held to maturity, 1 to 5 Years	204
Held to maturity, 6 to 10 Years	217
Held to maturity, Over 10 Years	15
Non-U.S. Debt Securities [Member] | Government Securities [Member]
Available for sale, Under 1 Year	1,671
Held to maturity, Under 1 Year	3
Non-U.S. Debt Securities [Member] | Other Non-U.S. Debt Securities [Member]
Available for sale, Under 1 Year	1,636
Available for sale, 1 to 5 Years	958
Available for sale, 6 to 10 Years	231
Held to maturity, 1 to 5 Years	155
Held to maturity, Over 10 Years	$ 17