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, 2013	Dec. 31, 2012
Investment Management Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading assets	$ 10,400	$ 10,961
Other assets	836	520
Subtotal assets of consolidated investment management funds, at fair value	11,236	11,481
Trading liabilities	9,908	10,152
Other liabilities	34	29
Subtotal liabilities of consolidated investment management funds, at fair value	$ 9,942	$ 10,181