Quarterly report pursuant to Section 13 or 15(d)

Available-for-Sale Securities, Weighted Average Life Classifications (Details)

v3.10.0.1
Available-for-Sale Securities, Weighted Average Life Classifications (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]    
Less than or equal to 1 year $ 101,583  
Greater than 1 year and less than or equal to 3 years 302,802  
Greater than 3 years and less than or equal to 5 years 672,709  
Greater than 5 years and less than or equal to 10 years 20,632,844  
Greater than 10 years 4,228,978  
Available-for-sale securities, at fair value 25,938,916 $ 21,220,819
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Debt Securities, Available-for-sale [Line Items]    
Less than or equal to 1 year 11,626  
Greater than 1 year and less than or equal to 3 years 110,610  
Greater than 3 years and less than or equal to 5 years 273,557  
Greater than 5 years and less than or equal to 10 years 18,130,930  
Greater than 10 years 3,592,223  
Available-for-sale securities, at fair value 22,118,946 18,238,725
Mortgage-backed Securities, Issued by Private Enterprises [Member]    
Debt Securities, Available-for-sale [Line Items]    
Less than or equal to 1 year 89,957  
Greater than 1 year and less than or equal to 3 years 192,192  
Greater than 3 years and less than or equal to 5 years 399,152  
Greater than 5 years and less than or equal to 10 years 2,501,914  
Greater than 10 years 636,755  
Available-for-sale securities, at fair value $ 3,819,970 $ 2,982,094