Annual report pursuant to Section 13 and 15(d)

Derivative Instruments and Hedging Activities - Notional Amounts of Derivative Positions (Details)

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Derivative Instruments and Hedging Activities - Notional Amounts of Derivative Positions (Details) - USD ($)
 12 Months Ended
Dec. 31, 2024
Dec. 31, 2023
Derivative, Notional Amount [Roll Forward]    
Additions $ 78,482,230,000 $ 28,242,326,000
Settlement, Termination, Expiration or Exercise (76,235,139,000) 1,066,469,000
Realized Gain (Loss), net (103,487,000) (100,057,000)
Inverse interest-only securities    
Derivative, Notional Amount [Roll Forward]    
Additions 0 0
Settlement, Termination, Expiration or Exercise (28,425,000) (32,721,000)
Realized Gain (Loss), net 0 0
Interest rate swap agreements    
Derivative, Notional Amount [Roll Forward]    
Additions 40,285,144,000 22,600,456,000
Settlement, Termination, Expiration or Exercise (41,478,791,000) (4,812,342,000)
Realized Gain (Loss), net (3,901,000) (36,114,000)
Swaptions, net    
Derivative, Notional Amount [Roll Forward]    
Additions (500,000,000) (400,000,000)
Settlement, Termination, Expiration or Exercise 700,000,000 200,000,000
Realized Gain (Loss), net (98,000) (80,000)
TBAs    
Derivative, Notional Amount [Roll Forward]    
Additions 63,434,400,000 42,018,000,000
Settlement, Termination, Expiration or Exercise (62,433,600,000) (42,347,000,000)
Realized Gain (Loss), net (68,791,000) (230,319,000)
Futures, net    
Derivative, Notional Amount [Roll Forward]    
Additions (25,011,200,000) (35,976,130,000)
Settlement, Termination, Expiration or Exercise 27,240,850,000 48,058,532,000
Realized Gain (Loss), net (30,570,000) 167,235,000
Options on futures    
Derivative, Notional Amount [Roll Forward]    
Additions 0 0
Settlement, Termination, Expiration or Exercise 0 0
Realized Gain (Loss), net (127,000) (779,000)
Interest rate lock commitments    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 0  
Additions 136,943,000  
Settlement, Termination, Expiration or Exercise (118,603,000)  
End of Period Notional Amount 18,340,000 0
Average Notional Amount (25,879,000)  
Realized Gain (Loss), net 0  
Forward mortgage loan sale commitments    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 0  
Additions 136,943,000  
Settlement, Termination, Expiration or Exercise (116,570,000)  
End of Period Notional Amount 20,373,000 0
Average Notional Amount (25,900,000)  
Realized Gain (Loss), net 0  
TBAs, net    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 15,045,799,000  
End of Period Notional Amount 17,292,890,000 15,045,799,000
Average Notional Amount 13,025,485,000 1,923,988,000
TBAs, net | Inverse interest-only securities    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 163,735,000 196,456,000
End of Period Notional Amount 135,310,000 163,735,000
Average Notional Amount (149,602,000) (180,080,000)
TBAs, net | Interest rate swap agreements    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 17,788,114,000 0
End of Period Notional Amount 16,594,467,000 17,788,114,000
Average Notional Amount (14,147,884,000) (7,974,494,000)
TBAs, net | TBAs    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 3,497,000,000 3,826,000,000
End of Period Notional Amount 4,497,800,000 3,497,000,000
Average Notional Amount (4,235,543,000) (3,016,532,000)
TBAs, net | Options on futures    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 0 0
End of Period Notional Amount 0 0
Average Notional Amount 0 0
Net Short Position    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount   14,262,996,000
End of Period Notional Amount    
Net Short Position | Swaptions, net    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 200,000,000 0
End of Period Notional Amount 0 200,000,000
Average Notional Amount (57,923,000) (161,644,000)
Net Short Position | Futures, net    
Derivative, Notional Amount [Roll Forward]    
Beginning of Period Notional Amount 6,203,050,000 18,285,452,000
End of Period Notional Amount 3,973,400,000 6,203,050,000
Average Notional Amount $ (5,501,400,000) $ (9,085,474,000)