Net Interest Revenue (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Interest revenue
Non-margin loans	$ 169	$ 171	$ 171
Margin loans	42	38	27
Securities:
Taxable	503	500	473
Exempt from federal income taxes	15	13	5
Total securities	518	513	478
Deposits with banks	114	118	128
Deposits with the Federal Reserve and other central banks	43	58	16
Federal funds sold and securities purchased under resale agreements	9	8	6
Trading assets	17	19	22
Total interest revenue	912	925	848
Interest expense
Deposits	43	59	48
Federal funds purchased and securities sold under repurchase agreements		(1)	1
Trading liabilities	4	4	13
Other borrowed funds	5	5	7
Customer payables	2	2	2
Long-term debt	93	76	79
Total interest expense	147	145	150
Net interest revenue	$ 765	$ 780	$ 698