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
Jun. 30, 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 88.70%  
Assets Reported at Fair Value, Trading Securities 8.30%  
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%  
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 $ 10,724,149 $ 6,249,252
Trading Securities, Fair Value Disclosure 999,375 1,003,301
Mortgages Held-for-sale, Fair Value Disclosure 11,378 5,782
Derivative Assets 361,073 251,856
Assets, Fair Value Disclosure 12,095,975 7,510,191
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 82,619 49,080
Liabilities, Fair Value Disclosure 82,619 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 999,375 1,003,301
Mortgages Held-for-sale, Fair Value Disclosure 0 0
Derivative Assets 0 2,664
Assets, Fair Value Disclosure 999,375 1,005,965
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 0 5,652
Liabilities, Fair Value Disclosure 0 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 10,724,149 6,238,136
Trading Securities, Fair Value Disclosure 0 0
Mortgages Held-for-sale, Fair Value Disclosure 11,378 0
Derivative Assets 361,073 249,192
Assets, Fair Value Disclosure 11,096,600 6,487,328
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 82,619 43,428
Liabilities, Fair Value Disclosure 82,619 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 0 5,782
Derivative Assets 0 0
Assets, Fair Value Disclosure 0 16,898
Derivative Financial Instruments, Liabilities, Fair Value Disclosure 0 0
Liabilities, Fair Value Disclosure $ 0 $ 0