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	3 Months Ended
	Mar. 31, 2015 investment		Dec. 31, 2014
Variable Interest Entity [Line Items]
Number of securitizations assessed for consolidation (investments)	1
VIE classification of carrying amount, assets	$ 809		$ 855
VIE classification of carrying amount, liabilities	142		148
Noncontrolling interest in VIE	479		544
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Available-for-sale	400		414
Trading assets	7,852		8,678
Other assets	573		604
Subtotal assets of consolidated investment management funds, at fair value	8,825		9,696
Trading liabilities	6,584		7,660
Other liabilities	391		372
Subtotal liabilities of consolidated investment management funds, at fair value	6,975		8,032
Nonredeemable noncontrolling interests of consolidated investment management funds	1,337		1,033
Variable Interest Entity, Primary Beneficiary | Investment Management funds
Variable Interest Entity [Line Items]
Available-for-sale	0		0
Trading assets	7,852		8,678
Other assets	573		604
Subtotal assets of consolidated investment management funds, at fair value	8,425	[1]	9,282	[2]
Trading liabilities	6,584		7,660
Other liabilities	36		9
Subtotal liabilities of consolidated investment management funds, at fair value	6,620	[1]	7,669	[2]
Nonredeemable noncontrolling interests of consolidated investment management funds	1,337	[1]	1,033	[2]
Variable Interest Entity, Primary Beneficiary | Securitizations
Variable Interest Entity [Line Items]
Available-for-sale	400		414
Trading assets	0		0
Other assets	0		0
Subtotal assets of consolidated investment management funds, at fair value	400		414
Trading liabilities	0		0
Other liabilities	355		363
Subtotal liabilities of consolidated investment management funds, at fair value	355		363
Nonredeemable noncontrolling interests of consolidated investment management funds	$ 0		$ 0

[1] Includes voting interest entities with assets of $809 million, liabilities of $142 million and nonredeemable noncontrolling interests of $479 million.

[2] Includes voting interest entities with assets of $855 million, liabilities of $148 million and nonredeemable noncontrolling interests of $544 million.