Quarterly report [Sections 13 or 15(d)]

Derivative Instruments and Hedging Activities - Derivative Instruments in Statement of Financial Position, Fair Value (Details)

v3.25.3
Derivative Instruments and Hedging Activities - Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($)
Sep. 30, 2025
Dec. 31, 2024
TBAs    
Notional Disclosures [Abstract]    
Notional $ (4,407,629,000) $ (4,497,800,000)
Futures, net    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 0
Notional Disclosures [Abstract]    
Notional (5,048,200,000) (3,973,400,000)
Interest rate lock commitments    
Derivative, Fair Value, Net [Abstract]    
Fair Value 1,100,000 100,000
Notional Disclosures [Abstract]    
Notional (63,100,000) (18,300,000)
Forward mortgage loan sale commitments    
Derivative, Fair Value, Net [Abstract]    
Fair Value   200,000
Notional Disclosures [Abstract]    
Notional 0 (20,400,000)
Derivative Assets    
Derivative, Fair Value, Net [Abstract]    
Fair Value 135,431,000 10,114,000
Notional Disclosures [Abstract]    
Notional (3,496,532,000) (12,757,134,000)
Derivative Assets | Inverse interest-only securities    
Derivative, Fair Value, Net [Abstract]    
Fair Value 133,313,000 9,058,000
Notional Disclosures [Abstract]    
Notional (2,181,910,000) (135,310,000)
Derivative Assets | Interest rate swap agreements    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 0
Notional Disclosures [Abstract]    
Notional 0 (16,594,467,000)
Derivative Assets | TBAs    
Derivative, Fair Value, Net [Abstract]    
Fair Value 1,050,000 732,000
Notional Disclosures [Abstract]    
Notional (693,371,000) (34,000,000)
Derivative Assets | Futures, net    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 0
Notional Disclosures [Abstract]    
Notional (5,048,200,000) (3,973,400,000)
Derivative Assets | Interest rate lock commitments    
Derivative, Fair Value, Net [Abstract]    
Fair Value 1,068,000 151,000
Notional Disclosures [Abstract]    
Notional (63,129,000) (15,727,000)
Derivative Assets | Forward mortgage loan sale commitments    
Derivative, Fair Value, Net [Abstract]    
Fair Value   173,000
Notional Disclosures [Abstract]    
Notional   (19,030,000)
Derivative Liabilities    
Derivative, Fair Value, Net [Abstract]    
Fair Value (7,720,000) (24,897,000)
Notional Disclosures [Abstract]    
Notional (29,982,904,000) (4,535,756,000)
Derivative Liabilities | Inverse interest-only securities    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 0
Notional Disclosures [Abstract]    
Notional 0 0
Derivative Liabilities | Interest rate swap agreements    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 0
Notional Disclosures [Abstract]    
Notional (24,881,904,000) 0
Derivative Liabilities | TBAs    
Derivative, Fair Value, Net [Abstract]    
Fair Value (7,720,000) (24,883,000)
Notional Disclosures [Abstract]    
Notional (5,101,000,000) (4,531,800,000)
Derivative Liabilities | Futures, net    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 0
Notional Disclosures [Abstract]    
Notional 0 0
Derivative Liabilities | Interest rate lock commitments    
Derivative, Fair Value, Net [Abstract]    
Fair Value 0 (13,000)
Notional Disclosures [Abstract]    
Notional $ 0 (2,613,000)
Derivative Liabilities | Forward mortgage loan sale commitments    
Derivative, Fair Value, Net [Abstract]    
Fair Value   (1,000)
Notional Disclosures [Abstract]    
Notional   $ (1,343,000)