Non-U.S. Activities (Summary Of Non-U.S. Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	$ 50,763	$ 58,886
Other assets	18,016	17,139
Total assets	222,582	216,827
Non-U.S. Assets [Member]
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	20,665	10,772
Investment securities	28,977	25,376
Other assets	7,040	10,246
Total assets	$ 56,682	$ 46,394