Quarterly report pursuant to Section 13 or 15(d)

Fair Value Fair Value, Measurement Inputs, Disclosure (Details)

v2.4.0.6
Fair Value Fair Value, Measurement Inputs, Disclosure (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Trading Securities Categorized as Level 1 Assets 100.00%  
Avaialble-for-sale Securities Categorized as Level 2 Assets 100.00%  
Assets Reported at Fair Value, Available-for-sale Securities 87.20%  
Assets Reported at Fair Value, Trading Securities 9.50%  
Mortgage Loans Held-for-sale Categorized as Level 3 Assets 100.00%  
Interest Rate Swaps, Swaptions and Credit Default Swaps Categorized as Level 2 Assets (Liabilities) 100.00%  
Inverse Interest-only Securities Categorized as Level 2 Assets 100.00%  
Agency To-be-Announced Securities Categoized as Level 1 Assets (Liabilities) 100.00%  
Fair Value, Measurements, Recurring [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Fair Value Disclosure $ 9,171,511 $ 6,249,252
Trading Securities, Fair Value Disclosure 1,002,090 1,003,301
Mortgages Held-for-sale, Fair Value Disclosure 5,711 5,782
Derivative Assets 340,715 251,856
Assets, Fair Value Disclosure 10,520,027 7,510,191
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 47,475 49,080
Liabilities, Fair Value Disclosure 47,475 49,080
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Fair Value Disclosure 0 0
Trading Securities, Fair Value Disclosure 1,002,090 1,003,301
Mortgages Held-for-sale, Fair Value Disclosure 0 0
Derivative Assets 1,484 2,664
Assets, Fair Value Disclosure 1,003,574 1,005,965
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 3,133 5,652
Liabilities, Fair Value Disclosure 3,133 5,652
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Fair Value Disclosure 9,171,511 6,238,136
Trading Securities, Fair Value Disclosure 0 0
Mortgages Held-for-sale, Fair Value Disclosure 0 0
Derivative Assets 339,231 249,192
Assets, Fair Value Disclosure 9,510,742 6,487,328
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 44,342 43,428
Liabilities, Fair Value Disclosure 44,342 43,428
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
   
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale Securities, Fair Value Disclosure 0 11,116
Trading Securities, Fair Value Disclosure 0 0
Mortgages Held-for-sale, Fair Value Disclosure 5,711 5,782
Derivative Assets 0 0
Assets, Fair Value Disclosure 5,711 16,898
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 0 0
Liabilities, Fair Value Disclosure $ 0 $ 0