Fair Value Option - Additional Information (Detail) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Option, Quantitative Disclosures [Line Items]
Commercial leveraged acquisition finance loans held for sale and related unfunded commitments, carried at fair value	$ 424,000,000	$ 377,000,000
Unpaid principal balance Commercial leveraged acquisition finance loans held for sale and related unfunded commitments ,carried at fair value	449,000,000	448,000,000
Fixed-rate debt accounted for under fair value option	2,000,000,000	1,700,000,000
Unpaid principal balance on fixed-rate debt accounted for under FVO	1,800,000,000	1,800,000,000
Interest bearing deposits in domestic offices	9,400,000,000	9,800,000,000
Unpaid balance on interest bearing deposits in domestic offices	9,000,000,000	9,600,000,000
Structured Notes, long term debt	5,700,000,000	3,400,000,000
Unpaid principal balance on structured notes, long term debt	$ 5,500,000,000	$ 3,500,000,000