Derivatives and Hedging Activities - Derivatives with Credit-Related Contingent Features (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Aggregate fair value of derivative contracts which are in net liability position	$ 35,906	$ 29,836
Aggregate fair value of assets as a collateral for derivative contracts	33,847	26,075
One-Notch Reduction [Member]
Derivative [Line Items]
Additional collateral or termination payments pursuant to bilateral agreements with certain counterparties which could have been called by counterparties in the event of a reduction in the firm's long-term credit ratings	774	1,061
Two-Notch Reduction [Member]
Derivative [Line Items]
Additional collateral or termination payments pursuant to bilateral agreements with certain counterparties which could have been called by counterparties in the event of a reduction in the firm's long-term credit ratings	$ 2,076	$ 2,689