Non-U.S. Activities (Summary Of Non-U.S. Assets) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	$ 44,783	$ 50,763
Other assets	26,602	18,016
Total assets	227,300	222,582
Non-U.S. Assets [Member]
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	7,808	20,665
Investment securities	28,875	28,976
Other assets	18,509	13,441
Total assets	$ 55,192	$ 63,082