Quarterly report pursuant to Section 13 or 15(d)

Repurchase Agreements Schedule of Repurchase Agreements by Maturity (Details)

v2.4.0.6
Repurchase Agreements Schedule of Repurchase Agreements by Maturity (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability $ 13,444,565 $ 12,624,510
Maturity up to 30 days [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability 2,014,206 3,038,229
Maturity 30 to 59 Days [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability 4,355,947 3,528,393
Maturity 60 to 89 Days [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability 2,501,381 1,731,595
Maturity 90 to 119 Days [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability 2,570,014 849,621
Maturity 120 to 364 days [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability 798,017 2,279,172
Maturity on Demand [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability 1,005,000 997,500
Maturity Over One Year [Member]
    
Assets Sold under Agreements to Repurchase [Line Items]    
Assets Sold under Agreements to Repurchase, Repurchase Liability $ 200,000 $ 200,000