Investments in Variable Interest Entities (Detail) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Variable Interest Entity, Consolidated
Schedule of Equity Method Investments [Line Items]
Amortized Cost	$ 7,189	$ 7,201
Fair value	7,214	7,363
Collateralized Debt Obligations | Variable Interest Entity, Not Consolidated
Schedule of Equity Method Investments [Line Items]
Amortized Cost	0	5
Fair value	0	5
Variable Interest Entity, Not Consolidated
Schedule of Equity Method Investments [Line Items]
Amortized Cost	13,948	13,919
Fair value	13,626	13,219
Variable Interest Entity, Not Consolidated | Other Debt and Perpetual Securities
Schedule of Equity Method Investments [Line Items]
Amortized Cost	13,948	13,914
Fair value	13,626	13,214
Variable Interest Entities
Schedule of Equity Method Investments [Line Items]
Amortized Cost	21,137	21,120
Fair value	$ 20,840	$ 20,582