Non-U.S. Activities (Summary Of Non-U.S. Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2010
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	$ 58,886	$ 22,234
Other assets	17,139	13,841	564,000
Total assets	216,827	160,505
Non-U.S. Assets [Member]
Segment Reporting Information [Line Items]
Interest-bearing deposits with banks	10,772	9,443
Non-U.S. investment securities	25,376	19,329
Other assets	15,518	13,994
Total assets	$ 51,666	$ 42,766