Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities Put and Call Options for TBAs (Details)

v3.19.1
Derivative Instruments and Hedging Activities Put and Call Options for TBAs (Details) - USD ($)
Mar. 31, 2019
Dec. 31, 2018
Mar. 31, 2018
Dec. 31, 2017
Derivative [Line Items]        
Notional $ 58,777,783,000 $ 36,528,169,000 $ 18,429,288,000 $ 31,226,878,000
Derivative Financial Instruments, Liabilities [Member]        
Derivative [Line Items]        
Notional 47,073,000 5,403,265,000    
Fair Value $ (231,000) (820,590,000)    
Put and Call Options for TBAs [Member] | Derivative Financial Instruments, Liabilities [Member]        
Derivative [Line Items]        
Notional   1,767,000,000    
Fair Value   (25,296,000)    
Put and Call Options for TBAs [Member] | Long [Member]        
Derivative [Line Items]        
Notional   5,400,000,000    
Put and Call Options for TBAs [Member] | Short [Member]        
Derivative [Line Items]        
Notional   $ 7,200,000,000