Fair Value Option- Assets and Liabilities, by Type, of Consolidated Investment Management Funds Recorded at Fair Value (Detail) (Investment Management funds, USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Investment Management funds
Assets of consolidated investment management funds:
Trading assets	$ 7,852	$ 8,678
Other assets	573	604
Subtotal assets of consolidated investment management funds, at fair value	8,425	9,282
Liabilities of consolidated investment management funds:
Trading liabilities	6,584	7,660
Other liabilities	36	9
Subtotal liabilities of consolidated investment management funds, at fair value	$ 6,620	$ 7,669