Mortgage Servicing Rights (Details 3) (Mortgage Servicing Rights.)	12 Months Ended
Dec. 31, 2011 Y	Dec. 31, 2010 Y
Mortgage Servicing Rights.
Key assumptions used in estimating the fair value of mortgage servicing rights
Weighted-Average Constant Prepayment Rate (as a percent)	15.56%	13.71%
Weighted-Average Life (in years)	5.03	5.90
Weighted-Average Note Rate (as a percent)	4.87%	5.02%
Weighted-Average Discount Rate (as a percent)	6.31%	7.29%

The discount rate which is used to value residual cash flows generated by financial assets of a securitization, asset-backed financing arrangement, or similar transfer. This is used as a key input and assumption in measuring the fair value of assets or liabilities that relate to a transferor's continuing involvement, if any, as of the date of the latest statement of financial position presented.

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Estimated speed of prepayments of principal on financial assets. This is used as a key input and assumption in measuring the fair value of assets or liabilities that relate to a transferor's continuing involvement, if any, as of the date of the latest statement of financial position presented.

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- Definition

The weighted average life of securitized assets. This is used as a key input and assumption in measuring the fair value of assets or liabilities that relate to a transferor's continuing involvement, if any, as of the date of the latest statement of financial position presented.

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