Annual report pursuant to Section 13 and 15(d)

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

v2.4.0.6
Derivative Instruments and Hedging Activities Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2012
Dec. 31, 2011
Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net $ 462,080 $ 251,856
Derivative Asset, Notional Amount 9,768,656 4,855,985
Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net (129,294) (49,080)
Derivative Liability, Notional Amount 14,209,000 6,814,812
Inverse Interest-Only Securities [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net 304,975 157,421
Derivative Asset, Notional Amount 1,909,351 1,131,084
Inverse Interest-Only Securities [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net 0 0
Derivative Liability, Notional Amount 0 0
Interest Rate Swap [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net 0 0
Derivative Asset, Notional Amount 0 0
Interest Rate Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net (129,055) (28,790)
Derivative Liability, Notional Amount 14,070,000 5,810,000
Credit Default Swap [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net 52,906 86,136
Derivative Asset, Notional Amount 438,440 544,699
Credit Default Swap [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net 0 (14,638)
Derivative Liability, Notional Amount 0 154,812
Interest Rate Swaption [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net 102,048 5,635
Derivative Asset, Notional Amount 4,950,000 2,900,000
Interest Rate Swaption [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net 0 0
Derivative Liability, Notional Amount 0 0
Other Contract [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net 1,917 2,664
Derivative Asset, Notional Amount 2,414,000 275,000
Other Contract [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net (239) (5,652)
Derivative Liability, Notional Amount 139,000 850,000
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net 234  
Derivative Asset, Notional Amount 56,865  
Forward Purchase Commitment [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net 0  
Derivative Liability, Notional Amount 0  
Forward Sale Commitment [Member] | Derivative Financial Instruments, Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Asset, Fair Value, Net   0
Derivative Asset, Notional Amount   5,202
Forward Sale Commitment [Member] | Derivative Financial Instruments, Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Derivative Liability, Fair Value, Net   0
Derivative Liability, Notional Amount   $ 0