Guarantee Arrangements and Pledged Assets and Collateral - Summary of Pledged Assets Included in Consolidated Balance Sheet (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Interest bearing deposits with banks	$ 324		$ 355
Trading assets	3,051	[1]	1,296	[1]
Securities available-for-sale	15,307	[2]	21,346	[2]
Securities held to maturity	327		362
Loans	3,732	[3]	3,969	[3]
Other assets	2,904	[4]	2,904	[4]
Total	$ 25,645		$ 30,232

[1] Trading assets are primarily pledged against liabilities associated with repurchase agreements.

[2] Securities available-for-sale are primarily pledged against derivatives, public fund deposits, trust deposits and various short-term and long term borrowings, as well as providing capacity for potential secured borrowings from the Federal Home Loan Bank and the Federal Reserve Bank.

[3] Loans are primarily residential mortgage loans pledged against long-term borrowings from the Federal Home Loan Bank.

[4] Other assets represent cash on deposit with non-banks related to derivative collateral support agreements.