Annual report pursuant to Section 13 and 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
Dec. 31, 2011
Dec. 31, 2010
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 99.80%  
Assets Reported at Fair Value, Available-for-sale Securities 83.20%  
Assets Reported at Fair Value, Trading Securities 13.40%  
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 $ 6,249,252 $ 1,354,405
Trading Securities, Fair Value Disclosure 1,003,301 199,523
Mortgages Held-for-sale, Fair Value Disclosure 5,782  
Derivative Assets 251,856 38,109
Assets, Fair Value Disclosure 7,510,191 1,592,037
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 49,080 158
Liabilities, Fair Value Disclosure 49,080 158
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 1,003,301 199,523
Mortgages Held-for-sale, Fair Value Disclosure 0  
Derivative Assets 2,664 0
Assets, Fair Value Disclosure 1,005,965 199,523
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 5,652 0
Liabilities, Fair Value Disclosure 5,652 0
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 6,238,136 1,345,805
Trading Securities, Fair Value Disclosure 0 0
Mortgages Held-for-sale, Fair Value Disclosure 0  
Derivative Assets 249,192 38,109
Assets, Fair Value Disclosure 6,487,328 1,383,914
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 43,428 158
Liabilities, Fair Value Disclosure 43,428 158
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 11,116 8,600
Trading Securities, Fair Value Disclosure 0 0
Mortgages Held-for-sale, Fair Value Disclosure 5,782  
Derivative Assets 0 0
Assets, Fair Value Disclosure 16,898 8,600
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 0 0
Liabilities, Fair Value Disclosure $ 0 $ 0