Net Interest Revenue (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Interest revenue
Non-margin loans	$ 165	$ 166	$ 169
Margin loans	38	42	42
Securities:
Taxable	441	449	503
Exempt from federal income taxes	24	25	15
Total securities	465	474	518
Deposits in banks	71	82	114
Deposits with the Federal Reserve and other central banks	31	37	43
Federal funds sold and securities purchased under resale agreements	10	9	9
Trading assets	35	33	17
Total interest revenue	815	843	912
Interest expense
Deposits	30	32	43
Federal funds purchased and securities sold under repurchase agreements	(3)	2	0
Trading liabilities	9	7	4
Other borrowed funds	2	4	5
Customer payables	2	2	2
Long-term debt	56	71	93
Total interest expense	96	118	147
Net interest revenue	$ 719	$ 725	$ 765