Non-U.S. Activities (Summary Of Non-U.S. Assets) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	$ 31,583	$ 58,886
Other assets	16,505	17,139
Total assets	204,522	216,827
Non-U.S. Assets [Member]
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	18,750	10,772
Investment securities	28,132	25,376
Other assets	11,361	10,246
Total assets	$ 58,243	$ 46,394