Collateralized Agreements and Financings - Other Secured Financings (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Collateralized Agreements And Financings [Abstract]
Transfers of financial assets accounted for as financings included in other secured financings	$ 478	$ 334
Financial assets collateralizing other secured financings related to failed sales	478	336
Other secured financings collateralized by financial instruments owned	14,060	14,980
Other secured financings collateralized by financial instruments received as collateral and repledged	$ 6,870	$ 8,760