Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Schedule of Total Return Swaps (Details)

v2.4.0.8
Derivative Instruments and Hedging Activities Schedule of Total Return Swaps (Details) (USD $)
In Thousands, unless otherwise specified
Sep. 30, 2014
Jun. 30, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Dec. 31, 2012
Derivative [Line Items]            
Derivative, Notional Amount $ (57,015,981) $ (43,379,217) $ (37,366,610) $ (36,472,401) $ (44,262,605) $ (22,377,656)
Total Return Swap [Member]
            
Derivative [Line Items]            
Derivative, Notional Amount (611,985)   (49,629)      
Derivative, Fair Value, Net 439   (134)      
Derivative, Cost (1,732)   (453)      
Derivative, Unrealized Gains (Losses) (1,293)   (587)      
Maturity Date, 1/12/2043 [Member] | Total Return Swap [Member]
            
Derivative [Line Items]            
Derivative, Notional Amount (421,143)   (49,629)      
Derivative, Fair Value, Net 318   (134)      
Derivative, Cost (1,457)   (453)      
Derivative, Unrealized Gains (Losses) (1,139)   (587)      
Maturity Date, 1/12/2044 [Member] | Total Return Swap [Member]
            
Derivative [Line Items]            
Derivative, Notional Amount (190,842)          
Derivative, Fair Value, Net 121          
Derivative, Cost (275)          
Derivative, Unrealized Gains (Losses) $ (154)