Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Cash Flows [Abstract]
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 2,334,000	$ 1,525,000	$ 2,324,000
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	557,000	89,000	866,000
Operating activities:
Net income (loss)	(1,190,000)	749,000	(266,000)
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of premiums and discounts on mortgage-backed securities, net	13,000	369,000	1,082,000
Stock based compensation	2,000	19,000	18,000
(Gain) loss on sale of investment securities, net	2,916,000	57,000	(1,126,000)
Unrealized (gain) loss on investment securities measured at fair value through net income, net	3,795,000	1,502,000	(319,000)
(Gain) loss on derivative instruments and other securities, net	(4,630,000)	(1,110,000)	2,463,000
(Increase) decrease in other assets	38,000	(29,000)	119,000
Increase (decrease) in other liabilities	69,000	(17,000)	(224,000)
Net cash provided by operating activities	1,013,000	1,540,000	1,747,000
Investing activities:
Purchases of Agency mortgage-backed securities	(26,842,000)	(45,345,000)	(56,521,000)
Purchases of credit risk transfer and non-Agency securities	(1,173,000)	(2,031,000)	(765,000)
Proceeds from sale of Agency mortgage-backed securities	25,978,000	34,595,000	77,294,000
Proceeds from sale of credit risk transfer and non-Agency securities	1,199,000	1,434,000	896,000
Principal collections on Agency mortgage-backed securities	6,525,000	15,042,000	17,373,000
Principal collections on credit risk transfer and non-Agency securities	209,000	84,000	131,000
Payments on U.S. Treasury securities	(27,494,000)	(22,055,000)	(24,497,000)
Proceeds from Sale of U.S. Treasury securities	25,878,000	19,795,000	25,978,000
Net proceeds from (payments on) reverse repurchase agreements	4,001,000	1,272,000	(1,530,000)
Net proceeds from (payments on) derivative instruments	2,907,000	1,045,000	(1,834,000)
Net cash provided by investing activities	11,188,000	3,836,000	36,525,000
Financing activities:
Proceeds from repurchase arrangements	2,360,328,000	2,189,555,000	3,133,008,000
Payments on repurchase agreements	(2,371,447,000)	(2,194,540,000)	(3,169,824,000)
Payments on debt of consolidated variable interest entities	(24,000)	(49,000)	(62,000)
Net proceeds from preferred stock issuance	(145,000)	0	(557,000)
Net proceeds from common stock issuance	526,000	0	439,000
Payments for common stock repurchases	(51,000)	(281,000)	(378,000)
Cash dividends paid	(869,000)	(860,000)	(970,000)
Net cash used in financing activities	(11,392,000)	(6,175,000)	(37,230,000)
Net change in cash and cash equivalents	809,000	(799,000)	$ 1,042,000
Cash and cash equivalents at end of period	$ 1,018,000	$ 998,000