Collateralized Agreements and Financings - Financial Instruments Owned, at Fair Value and Other Assets Pledged as Collateral (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Collateralized Agreements And Financings [Abstract]
Financial instruments owned at fair value pledged in connection with repurchase agreements, securities lending agreements and other secured financings to counterparties that had the right to deliver or repledge	$ 55,800	$ 54,426
Financial instruments owned at fair value pledged in connection with repurchase agreements, securities lending agreements and other secured financings to counterparties that did not have right to deliver or repledge	66,390	63,880
Other assets (substantially all real estate and cash) owned and pledged in connection with other secured financings to counterparties that did not have the right to deliver or repledge	$ 2,986	$ 1,841