Other Assets (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Corporate/bank owned life insurance	$ 4,230		$ 4,216
Accounts receivable	3,801		4,208
Equity in joint ventures and other investments	2,774	[1]	2,677	[1]
Income taxes receivable	2,714		2,573
Fails to deliver	1,157		961
Software	1,019		986
Fair value of hedging derivatives	1,035		1,600
Prepaid expenses	624		784
Due from customers on acceptances	300		321
Prepaid pension assets	160		144
Other	1,619		1,369
Total other assets	$ 19,433		$ 19,839

[1] Includes Federal Reserve Bank stock of $432 million and $429 million, respectively, at cost.