Annual report pursuant to Section 13 and 15(d)

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

v3.6.0.2
Schedule of Available-for-sale Securities Reconciliation (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value $ 16,303,556 $ 10,912,411
Available-for-sale Securities, Unamortized Premium 571,749 394,787
Available-for-sale Securities, Designated Credit Reserve (367,437) (409,077)
Available-for-sale Securities, Net, Unamortized (3,567,420) (3,429,000)
Available-for-sale Securities, Amortized Cost Basis 12,940,448 7,469,121
Available-for-sale Securities, Gross Unrealized Gains 432,398 427,595
Available-for-sale Securities, Gross Unrealized Losses (243,989) (71,396)
Available-for-sale securities, at fair value 13,128,857 7,825,320
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 13,571,417 8,257,030
Available-for-sale Securities, Unamortized Premium 571,749 394,787
Available-for-sale Securities, Designated Credit Reserve 0 0
Available-for-sale Securities, Net, Unamortized (2,758,445) (2,721,979)
Available-for-sale Securities, Amortized Cost Basis 11,384,721 5,929,838
Available-for-sale Securities, Gross Unrealized Gains 79,040 98,389
Available-for-sale Securities, Gross Unrealized Losses (237,287) (55,337)
Available-for-sale securities, at fair value 11,226,474 5,972,890
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 2,732,139 2,655,381
Available-for-sale Securities, Unamortized Premium 0 0
Available-for-sale Securities, Designated Credit Reserve (367,437) (409,077)
Available-for-sale Securities, Net, Unamortized (808,975) (707,021)
Available-for-sale Securities, Amortized Cost Basis 1,555,727 1,539,283
Available-for-sale Securities, Gross Unrealized Gains 353,358 329,206
Available-for-sale Securities, Gross Unrealized Losses (6,702) (16,059)
Available-for-sale securities, at fair value $ 1,902,383 $ 1,852,430