Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Schedule of Interest Rate Swaps Associated with Repurchase Agreements (Details)

v2.4.0.6
Derivative Instruments and Hedging Activities Schedule of Interest Rate Swaps Associated with Repurchase Agreements (Details) (Swap [Member], USD $)
In Thousands, unless otherwise specified
Sep. 30, 2012
Dec. 31, 2011
Derivative [Line Items]    
Derivative, Notional Amount $ 12,095,000 $ 4,385,000
Derivative, Average Fixed Interest Rate 0.8412% 0.9523%
Derivative, Average Variable Interest Rate 0.4501% 0.3611%
Derivative, Weighted Average Remaining Maturity 2.987 2.406
Derivative Maturity Within One Year From Balance Sheet Date [Member]
   
Derivative [Line Items]    
Derivative, Notional Amount 25,000 25,000
Derivative, Average Fixed Interest Rate 0.8675% 0.8675%
Derivative, Average Variable Interest Rate 0.5023% 0.315%
Derivative, Weighted Average Remaining Maturity .225 .975
Derivative Maturity Over One And Within Two Years From Balance Sheet Date [Member]
   
Derivative [Line Items]    
Derivative, Notional Amount 2,275,000 2,025,000
Derivative, Average Fixed Interest Rate 0.713% 0.7366%
Derivative, Average Variable Interest Rate 0.4839% 0.368%
Derivative, Weighted Average Remaining Maturity .808 1.546
Derivative Maturity Over Two And Within Three Years From Balance Sheet Date [Member]
   
Derivative [Line Items]    
Derivative, Notional Amount 1,675,000 1,275,000
Derivative, Average Fixed Interest Rate 0.644% 0.6699%
Derivative, Average Variable Interest Rate 0.4972% 0.3801%
Derivative, Weighted Average Remaining Maturity 1.816 2.719
Derivative Maturity Over Three And Within Four Years From Balance Sheet Date [Member]
   
Derivative [Line Items]    
Derivative, Notional Amount 2,770,000 820,000
Derivative, Average Fixed Interest Rate 0.9079% 1.5747%
Derivative, Average Variable Interest Rate 0.4714% 0.329%
Derivative, Weighted Average Remaining Maturity 2.677 3.524
Derivative Maturity Over Four Years From Balance Sheet Date [Member]
   
Derivative [Line Items]    
Derivative, Notional Amount $ 5,350,000 $ 240,000
Derivative, Average Fixed Interest Rate 0.9227% 2.1556%
Derivative, Average Variable Interest Rate 0.4096% 0.3158%
Derivative, Weighted Average Remaining Maturity 4.453 4.322