Sensitivity of the Current Fair Value of Residual Cash Flows to Immediate 10% and 20% Adverse Changes in Assumptions (Detail) (USD $)	Dec. 31, 2011
Fixed Rate Residential Mortgage
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair Value	$ 649,000,000
Weighted- Average Life (in years)	5.0
Rate	17.90%
Impact of Adverse Change on Fair Value 10%	(36,000,000)
Impact of Adverse Change on Fair Value 20%	(68,000,000)
Discount Rate	10.60%
Impact of Adverse Change on Fair Value 10%	(23,000,000)
Impact of Adverse Change on Fair Value 20%	(43,000,000)
Adjustable Rate Residential Mortgage
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair Value	32,000,000
Weighted- Average Life (in years)	3.0
Rate	28.70%
Impact of Adverse Change on Fair Value 10%	(2,000,000)
Impact of Adverse Change on Fair Value 20%	(3,000,000)
Discount Rate	11.80%
Impact of Adverse Change on Fair Value 10%	(1,000,000)
Impact of Adverse Change on Fair Value 20%	$ (2,000,000)

The carrying amount (fair value) as of the balance sheet date of the transferor's interests in transferred financial assets (typically securitized receivables, generally not involved in the collection of principal) following transfer of significant portions of such financial instruments to other parties. Such interests could be ancillary cash flows and interest-only strips.

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The hypothetical financial impact of a 10 percent adverse change of the discount rate on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

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- Definition

The hypothetical financial impact of a 10 percent adverse change of prepayment speed on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

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- Definition

The hypothetical financial impact of a 20 percent adverse change of the discount rate on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

+ References+ Details

- Definition

The hypothetical financial impact of a 20 percent adverse change of prepayment speed on the fair value of transferor's interests in transferred financial assets (including any servicing assets or servicing liabilities) as of the balance sheet date.

+ References+ Details