Asset Transfers in Which the Company has Continuing Economic Involvement (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Cash flows on interests held	$ 12	[1]	$ 9	[1]	$ 19	[1]	$ 16	[1]
Servicing or management fees	3	[1]	3	[1]	6	[1]	6	[1]
Residential Mortgage
Cash flows on interests held	11	[1],[2]	8	[1],[2]	17	[1],[2]	15	[1],[2]
Servicing or management fees	1	[1],[2]	1	[1],[2]	1	[1],[2]	1	[1],[2]
Commercial and Corporate Loans [Member]
Cash Flows Between Transferor and Transferee, Servicing Fee Advances	0	[1]	0	[1]	1	[1]	0	[1]
Servicing or management fees	2	[1]	2	[1]	5	[1]	5	[1]
Collateralized Debt Obligations [Member]
Cash flows on interests held	$ 1	[1]	$ 1	[1]	$ 1	[1]	$ 1	[1]

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

[2] Does not include GSE mortgage loan transfers