|
Mortgage Banking Activities Textuals (Details) (USD $)
|
12 Months Ended | 3 Months Ended | 12 Months Ended | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Dec. 31, 2011
|
Mar. 31, 2012
Retained earnings [Member]
|
Dec. 31, 2011
Retained earnings [Member]
|
Mar. 31, 2013
Liability For Mortgage Loans Repurchase Losses [Member]
|
Mar. 31, 2013
Commercial Mortgage Servicing [Member]
|
Dec. 31, 2012
Commercial Mortgage Servicing [Member]
|
Mar. 31, 2012
Commercial Mortgage Servicing [Member]
|
Dec. 31, 2011
Commercial Mortgage Servicing [Member]
|
Dec. 31, 2011
Residential Mortgage Servicing [Member]
|
Mar. 31, 2012
Residential Mortgage Servicing [Member]
Election of fair value option [Member]
|
Mar. 31, 2013
Amortized [Member]
|
Dec. 31, 2012
Amortized [Member]
|
Mar. 31, 2012
Amortized [Member]
|
Dec. 31, 2011
Amortized [Member]
|
Mar. 31, 2012
Amortized [Member]
Residential Mortgage Servicing [Member]
|
|
| Mortgage Banking Activities (Textual) [Abstract] | |||||||||||||||
| Residential MSRs transferred from amortized MSRs | $ 315,000,000 | ||||||||||||||
| Residential MSRs transferred to MSRs carried at Fair Value, Gross | 350,000,000 | ||||||||||||||
| Residential MSRs transferred to MSRs carried at Fair Value, Net | 313,000,000 | ||||||||||||||
| Cumulative effect of fair value election for certain residential mortgage servicing rights | 2,000,000 | 2,000,000 | 2,000,000 | ||||||||||||
| Fair Value of amortized MSRs | 1,404,000,000 | 1,400,000,000 | 1,263,000,000 | 1,440,000,000 | 316,000,000 | 1,404,000,000 | 1,400,000,000 | 1,263,000,000 | 1,756,000,000 | ||||||
| Loss Contingency, Range of Possible Loss, Portion Not Accrued | $ 2,200,000,000 | ||||||||||||||