Securitizations and Variable Interest Entities- Incremental Assets and Liabilities of Variable Interest Entities Included in Consolidated Financial Statements (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 investment	Sep. 30, 2014 Variable Interest Entity, Primary Beneficiary	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary	Sep. 30, 2014 Variable Interest Entity, Primary Beneficiary Investment Management funds	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary Investment Management funds	Sep. 30, 2014 Variable Interest Entity, Primary Beneficiary Securitizations	Dec. 31, 2013 Variable Interest Entity, Primary Beneficiary Securitizations
Variable Interest Entity [Line Items]
Number of securitizations assessed for consolidation (investments)	2
Available-for-sale		$ 415	$ 487	$ 0	$ 0	$ 415	$ 487
Trading assets		8,823	10,397	8,823	10,397	0	0
Other assets		739	875	739	875	0	0
Subtotal assets of consolidated investment management funds, at fair value		9,977	11,759	9,562	11,272	415	487
Trading liabilities		8,130	10,085	8,130	10,085	0	0
Other liabilities		364	484	10	46	354	438
Subtotal liabilities of consolidated investment management funds, at fair value		8,494	10,569	8,140	10,131	354	438
Nonredeemable noncontrolling interests of consolidated investment management funds		$ 901	$ 783	$ 901	$ 783	$ 0	$ 0