Derivatives Volume of Activity (Details) $ in Thousands	6 Months Ended
Derivatives Volume of Activity (Details) $ in Thousands	Jun. 30, 2026 USD ($)
Not Designated as Hedging Instrument, Economic Hedge \| U.S. Treasury futures \| Short position
Derivatives [Roll Forward]
Beginning Notional Amount-Long (Short)	$ 2,658,500
Additions	(14,876,500)
Settlements, Terminations, or Pair-Offs	(13,276,700)
Ending Notional Amount-Long (Short)	4,258,300
Not Designated as Hedging Instrument, Economic Hedge \| Interest rate swaps \| Short position
Derivatives [Roll Forward]
Beginning Notional Amount-Long (Short)	9,685,000
Additions	(4,415,000)
Settlements, Terminations, or Pair-Offs	10,000
Ending Notional Amount-Long (Short)	14,090,000
Not Designated as Hedging Instrument, Economic Hedge \| Interest rate swaps \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount-Long (Short)	9,685,000
Ending Notional Amount-Long (Short)	14,090,000
Not Designated as Hedging Instrument, Economic Hedge \| Interest Rate Swaption \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount-Long (Short)	750,000
Additions	0
Ending Notional Amount-Long (Short)	750,000
Not Designated as Hedging Instrument, Economic Hedge \| Exchange Traded Options \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount-Long (Short)	500,000
Additions	0
Settlements, Terminations, or Pair-Offs	(500,000)
Ending Notional Amount-Long (Short)	0
Not Designated as Hedging Instrument, Trading \| TBA securities \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount-Long (Short)	3,189,000
Additions	(22,929,000)
Settlements, Terminations, or Pair-Offs	(23,558,000)
Ending Notional Amount-Long (Short)	$ 2,560,000