Asset Transfers in Which the Company has Continuing Economic Involvement (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Cash flows on interests held	$ 30	[1]	$ 51	[1]	$ 80	[1]
Servicing or management fees	13	[1]	13	[1]	17	[1]
Residential Mortgage
Cash flows on interests held	27	[1]	48	[1]	66	[1]
Servicing or management fees	3	[1]	3	[1]	4	[1]
Commercial and Corporate Loans [Member]
Cash flows on interests held	1	[1]	1	[1]	4	[1]
Servicing or management fees	10	[1]	10	[1]	12	[1]
Student Loans [Member]
Cash flows on interests held			0	[1]	8	[1]
Servicing or management fees					1	[1]
Collateralized Debt Obligations [Member]
Cash flows on interests held	$ 2	[1]	$ 2	[1]	$ 2	[1]

[1] The transfer activity is related to unconsolidated VIEs.