Other Assets - Goodwill and Intangible Assets (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	$ 3,669	$ 3,657
Identifiable Intangible Assets	435	491
Investment Banking - Financial Advisory [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	98	98
Investment Banking - Underwriting [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	183	183
Institutional Client Services - Fixed Income, Currency and Commodities Client Execution [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	269	269
Identifiable Intangible Assets	70	92
Institutional Client Services - Equities Client Execution [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	2,403	2,402
Identifiable Intangible Assets	149	193
Institutional Client Services - Securities Services [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	105	105
Investing and Lending [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	2	2
Identifiable Intangible Assets	92	75
Investment Management [Member]
Schedule Of Intangible Assets And Goodwill [Line Items]
Goodwill	609	598
Identifiable Intangible Assets	$ 124	$ 131