Non-U.S. Activities (Summary Of Non-U.S. Assets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	$ 26,709	$ 58,886
Other assets	13,726	17,139
Total assets	187,956	216,827
Non-U.S. Assets [Member]
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	15,901	10,772
Non-U.S. investment securities	27,315	25,376
Other assets	9,391	12,573
Total assets	$ 52,607	$ 48,721