Quarterly report pursuant to Section 13 or 15(d)

Schedule of Available-for-sale Securities Reconciliation (Details)

v2.4.0.6
Schedule of Available-for-sale Securities Reconciliation (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2013
Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Gross Unrealized Gains $ 889,179 $ 724,696
Available-for-sale Securities, Gross Unrealized Losses 88,469 28,238
Available-for-sale securities, at fair value 14,963,531 13,666,954
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 13,177,863 11,934,492
Available-for-sale Securities, Unamortized Premium 777,288 749,252
Available-for-sale Securities, Designated Credit Reserve 0 0
Available-for-sale Securities, Net, Unamortized (2,164,457) (1,929,811)
Available-for-sale Securities, Amortized Cost Basis 11,790,694 10,753,933
Available-for-sale Securities, Gross Unrealized Gains 224,677 276,293
Available-for-sale Securities, Gross Unrealized Losses (82,816) (18,123)
Available-for-sale securities, at fair value 11,932,555 11,012,103
Mortgage-backed Securities, Issued by Private Enterprises [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 4,722,060 4,503,999
Available-for-sale Securities, Unamortized Premium 0 0
Available-for-sale Securities, Designated Credit Reserve (1,376,693) (1,290,946)
Available-for-sale Securities, Net, Unamortized (973,240) (996,490)
Available-for-sale Securities, Amortized Cost Basis 2,372,127 2,216,563
Available-for-sale Securities, Gross Unrealized Gains 664,502 448,403
Available-for-sale Securities, Gross Unrealized Losses (5,653) (10,115)
Available-for-sale securities, at fair value 3,030,976 2,654,851
Collateralized Mortgage Backed Securities [Member]
   
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 17,899,923 16,438,491
Available-for-sale Securities, Unamortized Premium 777,288 749,252
Available-for-sale Securities, Designated Credit Reserve (1,376,693) (1,290,946)
Available-for-sale Securities, Net, Unamortized (3,137,697) (2,926,301)
Available-for-sale Securities, Amortized Cost Basis 14,162,821 12,970,496
Available-for-sale Securities, Gross Unrealized Gains 889,179 724,696
Available-for-sale Securities, Gross Unrealized Losses (88,469) (28,238)
Available-for-sale securities, at fair value $ 14,963,531 $ 13,666,954