Non-Consolidated Variable Interest Entities - Additional Information (Detail) (Variable Interest Entity, Not Primary Beneficiary, USD $) In Millions	3 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Non-consolidated VIEs, unpaid principal balance of loans serviced	$ 9,400	$ 9,300	$ 9,300
Non-consolidated VIEs, description of maximum loss	Maximum exposure to loss represents the maximum loss, under a worst case scenario, that would be incurred by the Corporation, as servicer for the VIEs, assuming all loans serviced are delinquent and that the value of the Corporation’s interests and any associated collateral declines to zero, without any consideration of recovery.