Quarterly report pursuant to Section 13 or 15(d)

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details)

v2.4.0.8
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) (USD $)
In Thousands, unless otherwise specified
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2012
Notional Disclosures [Abstract]            
Derivative, Notional Amount $ 43,379,217 $ 43,576,146 $ 37,366,610 $ 44,262,605 $ 27,041,328 $ 22,377,656
Inverse Interest-Only Securities [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount 1,323,650 1,412,374 1,525,845 1,798,972 1,960,087 1,909,351
Interest Rate Swap [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount 23,628,148 21,663,148 19,619,000 18,485,000 16,685,000 14,070,000
Credit Default Swap [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount 125,000 125,000 427,073 1,630,404 437,496 438,440
Interest Rate Swaption [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount 11,450,000 9,500,000 5,130,000 6,250,000 5,800,000 4,950,000
Forward Contracts [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount (372,000) (1,022,000) 603,000 (2,721,000) 2,150,000 953,000
Options Held [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0 1,500,000 0 (210,000) 0 0
Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net (772)   (3,773)      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 6,000,000 10,000,000 10,000,000 19,000,000 0 0
Total Return Swap [Member]
           
Notional Disclosures [Abstract]            
Derivative, Notional Amount 576,478 243,987 49,629      
Forward Purchase Commitment [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 3,444          
Notional Disclosures [Abstract]            
Derivative, Notional Amount 647,941 153,637 12,063 29,229 8,745 56,865
Derivative Financial Instruments, Assets [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 331,601   549,859      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 38,499,739   30,383,908      
Derivative Financial Instruments, Assets [Member] | Inverse Interest-Only Securities [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 207,260   221,364      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 1,323,650   1,525,845      
Derivative Financial Instruments, Assets [Member] | Interest Rate Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 4,978   25,325      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 23,628,148   19,619,000      
Derivative Financial Instruments, Assets [Member] | Credit Default Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0   0      
Derivative Financial Instruments, Assets [Member] | Interest Rate Swaption [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 106,828   269,745      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 11,450,000   5,130,000      
Derivative Financial Instruments, Assets [Member] | Forward Contracts [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 9,063   33,425      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 1,450,000   4,097,000      
Derivative Financial Instruments, Assets [Member] | Options Held [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 28          
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0          
Derivative Financial Instruments, Assets [Member] | Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0   0      
Derivative Financial Instruments, Assets [Member] | Total Return Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0   0      
Derivative Financial Instruments, Assets [Member] | Forward Purchase Commitment [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net     0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount     12,063      
Derivative Financial Instruments, Liabilities [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net (17,097)   (22,081)      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 8,523,478   10,876,702      
Derivative Financial Instruments, Liabilities [Member] | Inverse Interest-Only Securities [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0   0      
Derivative Financial Instruments, Liabilities [Member] | Interest Rate Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0   0      
Derivative Financial Instruments, Liabilities [Member] | Credit Default Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net (2,081)   (18,049)      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 125,000   427,073      
Derivative Financial Instruments, Liabilities [Member] | Interest Rate Swaption [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0   0      
Derivative Financial Instruments, Liabilities [Member] | Forward Contracts [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net (13,566)   (125)      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 1,822,000   400,000      
Derivative Financial Instruments, Liabilities [Member] | Options Held [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0          
Notional Disclosures [Abstract]            
Derivative, Notional Amount 0          
Derivative Financial Instruments, Liabilities [Member] | Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net (772)   (3,773)      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 6,000,000   10,000,000      
Derivative Financial Instruments, Liabilities [Member] | Total Return Swap [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net (678)   (134)      
Notional Disclosures [Abstract]            
Derivative, Notional Amount 576,478   49,629      
Derivative Financial Instruments, Liabilities [Member] | Forward Purchase Commitment [Member]
           
Derivative, Fair Value, Net [Abstract]            
Derivative, Fair Value, Net 0   0      
Notional Disclosures [Abstract]            
Derivative, Notional Amount $ 0   $ 0