Guarantee Arrangements and Pledged Assets and Collateral - Net Credit Derivative Positions (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Credit Derivatives [Line Items]
Credit Risk Derivative Liabilities, at Fair Value	$ 5,098		$ 5,614
Credit Risk Derivatives, at Fair Value, Net	(152)	[1]	(40)	[1]
Credit Derivative, Maximum Exposure, Undiscounted	4,660	[1]	(5,474)	[1]
Sell Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Risk Derivative Liabilities, at Fair Value	569		545
Credit Derivative, Maximum Exposure, Undiscounted	171,067		180,380
Buy Protection Credit Derivatives [Member]
Credit Derivatives [Line Items]
Credit Risk Derivative Assets, at Fair Value	417		505
Credit Derivative, Maximum Exposure, Undiscounted	$ 175,727		$ 174,906

[1] Positions are presented net in the table above to provide a complete analysis of our risk exposure and depict the way we manage our credit derivative portfolio. The offset of the sell-protection credit derivatives against the buy-protection credit derivatives may not be legally binding in the absence of master netting agreements with the same counterparty. Furthermore, the credit loss triggering events for individual sell protection credit derivatives may not be the same or occur in the same period as those of the buy protection credit derivatives thereby not providing an exact offset.