Collateralized Agreements and Financings - Offsetting Arrangements (Parenthetical) (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Collateralized Agreements And Financings [Abstract]
Securities received under resale agreements segregated to satisfy certain regulatory requirements	$ 15,060	$ 13,400
Securities borrowed transactions segregated to satisfy certain regulatory requirements	$ 1,810	$ 5,540

Fair value of reverse repurchase agreements deposited in a special reserve account for the exclusive benefit of customers.

No definition available.

Name:	us-gaap_ReverseRepurchaseAgreementsSegregatedUnderSecuritiesExchangeCommissionRegulation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant