Quarterly report pursuant to Section 13 or 15(d)

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

v3.7.0.1
Schedule of Available-for-sale Securities Reconciliation (Details) - USD ($)
$ in Thousands
Mar. 31, 2017
Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value $ 20,381,686 $ 16,303,556
Available-for-sale Securities, Unamortized Premium 769,384 571,749
Available-for-sale Securities, Designated Credit Reserve (442,856) (367,437)
Available-for-sale Securities, Net, Unamortized (3,676,715) (3,567,420)
Available-for-sale Securities, Amortized Cost Basis 17,031,499 12,940,448
Available-for-sale Securities, Gross Unrealized Gains 476,923 432,398
Available-for-sale Securities, Gross Unrealized Losses (189,725) (243,989)
Available-for-sale securities, at fair value 17,318,697 13,128,857
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 17,294,143 13,571,417
Available-for-sale Securities, Unamortized Premium 769,384 571,749
Available-for-sale Securities, Designated Credit Reserve 0 0
Available-for-sale Securities, Net, Unamortized (2,840,374) (2,758,445)
Available-for-sale Securities, Amortized Cost Basis 15,223,153 11,384,721
Available-for-sale Securities, Gross Unrealized Gains 81,271 79,040
Available-for-sale Securities, Gross Unrealized Losses (184,539) (237,287)
Available-for-sale securities, at fair value 15,119,885 11,226,474
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Available-for-sale Securities, Face Value 3,087,543 2,732,139
Available-for-sale Securities, Unamortized Premium 0 0
Available-for-sale Securities, Designated Credit Reserve (442,856) (367,437)
Available-for-sale Securities, Net, Unamortized (836,341) (808,975)
Available-for-sale Securities, Amortized Cost Basis 1,808,346 1,555,727
Available-for-sale Securities, Gross Unrealized Gains 395,652 353,358
Available-for-sale Securities, Gross Unrealized Losses (5,186) (6,702)
Available-for-sale securities, at fair value $ 2,198,812 $ 1,902,383