Schedule of Derivative Instruments in Statement of Financial Position, Fair Value (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Notional Disclosures [Abstract]
Derivative, Notional Amount	$ (17,159,801,000)	$ (23,932,603,000)	$ (48,445,497,000)
U.S. Treasury and Eurodollar Futures [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	35,362,000	3,675,000
Notional Disclosures [Abstract]
Derivative, Notional Amount	(5,829,600,000)	(2,021,100,000)
Derivative assets
Derivative, Fair Value, Net [Abstract]
Fair Value	80,134,000	95,937,000
Notional Disclosures [Abstract]
Derivative, Notional Amount	(18,327,801,000)	(10,039,262,000)
Derivative assets | Inverse Interest-Only Securities [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	41,367,000	62,200,000
Notional Disclosures [Abstract]
Derivative, Notional Amount	(247,101,000)	(318,162,000)
Derivative assets | Interest Rate Swap [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	0	0
Notional Disclosures [Abstract]
Derivative, Notional Amount	(20,387,300,000)	0
Derivative assets | Interest Rate Swaption [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	0	0
Notional Disclosures [Abstract]
Derivative, Notional Amount	0	0
Derivative assets | TBAs [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	3,405,000	30,062,000
Notional Disclosures [Abstract]
Derivative, Notional Amount	(3,523,000,000)	(7,700,000,000)
Derivative assets | U.S. Treasury and Eurodollar Futures [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	35,362,000	3,675,000
Notional Disclosures [Abstract]
Derivative, Notional Amount	(5,829,600,000)	(2,021,100,000)
Derivative liabilities
Derivative, Fair Value, Net [Abstract]
Fair Value	(53,658,000)	(11,058,000)
Notional Disclosures [Abstract]
Derivative, Notional Amount	(1,168,000,000)	(13,893,341,000)
Derivative liabilities | Inverse Interest-Only Securities [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	0	0
Notional Disclosures [Abstract]
Derivative, Notional Amount	0	0
Derivative liabilities | Interest Rate Swap [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	0	0
Notional Disclosures [Abstract]
Derivative, Notional Amount	0	(12,646,341,000)
Derivative liabilities | Interest Rate Swaption [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	(51,743,000)	(596,000)
Notional Disclosures [Abstract]
Derivative, Notional Amount	(1,761,000,000)	(3,750,000,000)
Derivative liabilities | TBAs [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	(1,915,000)	(10,462,000)
Notional Disclosures [Abstract]
Derivative, Notional Amount	(593,000,000)	(2,503,000,000)
Derivative liabilities | U.S. Treasury and Eurodollar Futures [Member]
Derivative, Fair Value, Net [Abstract]
Fair Value	0	0
Notional Disclosures [Abstract]
Derivative, Notional Amount	$ 0	$ 0