Other Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Other Assets [Abstract]
Accounts receivable	$ 4,514		$ 4,255
Corporate/bank owned life insurance	4,376		4,360
Income taxes receivable	3,049		3,099
Equity in joint ventures and other investments (a)	2,784	[1]	2,664	[1]
Fails to deliver	2,124		1,148
Fair value of hedging derivatives	1,135		989
Software	1,130		1,117
Prepaid expenses	575		508
Prepaid pension assets	436		419
Due from customers on acceptances	421		376
Other	1,160		1,533
Total other assets	$ 21,704		$ 20,468

[1] Includes Federal Reserve Bank stock of $436 million and $436 million, respectively, at cost.