Derivatives Volume of Activity (Details) $ in Thousands	9 Months Ended
Derivatives Volume of Activity (Details) $ in Thousands	Sep. 30, 2026 USD ($)
Not Designated as Hedging Instrument, Economic Hedge \| U.S. Treasury futures \| Short position
Derivatives [Roll Forward]
Beginning Notional Amount	$ 2,658,500
Additions	(30,585,500)
Settlements, Terminations, or Pair-Offs	(26,567,500)
Ending Notional Amount	6,676,500
Not Designated as Hedging Instrument, Economic Hedge \| Interest rate swaps \| Short position
Derivatives [Roll Forward]
Beginning Notional Amount	9,685,000
Additions	(8,892,000)
Settlements, Terminations, or Pair-Offs	980,000
Ending Notional Amount	17,597,000
Not Designated as Hedging Instrument, Economic Hedge \| Interest rate swaps \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount	9,685,000
Ending Notional Amount	17,597,000
Not Designated as Hedging Instrument, Economic Hedge \| Interest Rate Swaption \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount	750,000
Additions	0
Ending Notional Amount	750,000
Not Designated as Hedging Instrument, Economic Hedge \| Exchange Traded Options \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount	500,000
Additions	(887,600)
Settlements, Terminations, or Pair-Offs	(1,387,600)
Ending Notional Amount	0
Not Designated as Hedging Instrument, Trading \| TBA securities \| Long position
Derivatives [Roll Forward]
Beginning Notional Amount	3,189,000
Additions	(33,500,000)
Settlements, Terminations, or Pair-Offs	(34,126,000)
Ending Notional Amount	$ 2,563,000