CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands		Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit		Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjusted Balance	Total Stockholders’ Equity	Noncontrolling Interest
Beginning balance at Dec. 31, 2017			$ 1,720,381	$ 11,596	$ 17,221,265	$ (1,126,020)	$ (2,961,749)		$ 0	$ (2,961,749)		$ 6,100
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance			411,335	1,103	1,116,409
Buyback of common stock				0	0
Acquisition of subsidiary			55,000	436	455,507
Stock-based award activity				0	1,961
Redemption of preferred stock			(408,548)		(3,952)
Direct purchase and dividend reinvestment				3	3,141
Unrealized gains (losses) on available-for-sale securities		$ (2,004,166)				(2,004,166)
Reclassification adjustment for net gains (losses) included in net income (loss)		1,150,321				1,150,321
Net income (loss) attributable to Annaly		54,408					54,408
Dividends declared on preferred stock	[1]						(129,312)
Dividends and dividend equivalents declared on common stock and share-based awards	[1]						(1,457,007)
Net income (loss) attributable to noncontrolling interests		260										(260)
Equity contributions from (distributions to) noncontrolling interests												(151)
Ending balance at Dec. 31, 2018		14,117,801	1,778,168	13,138	18,794,331	(1,979,865)	(4,493,660)		0	(4,493,660)	$ 14,112,112	5,689
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance			428,324	1,422	1,397,484
Buyback of common stock				(261)	(223,313)
Acquisition of subsidiary			0	0	0
Stock-based award activity				0	2,162
Redemption of preferred stock			(224,466)		(5,534)
Direct purchase and dividend reinvestment		1,795		2	1,793
Unrealized gains (losses) on available-for-sale securities		4,135,862				4,135,862
Reclassification adjustment for net gains (losses) included in net income (loss)		(17,806)				(17,806)
Net income (loss) attributable to Annaly		(2,162,865)					(2,162,865)
Dividends declared on preferred stock	[1]						(136,576)
Dividends and dividend equivalents declared on common stock and share-based awards		(1,516,323)					(1,516,323)	[1]
Net income (loss) attributable to noncontrolling interests		226										(226)
Equity contributions from (distributions to) noncontrolling interests												(1,136)
Ending balance at Dec. 31, 2019		15,796,344	1,982,026	14,301	19,966,923	2,138,191	(8,309,424)		$ (39,641)	$ (8,349,065)	15,792,017	4,327
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance			0	0	(93)
Buyback of common stock				(324)	(209,094)
Acquisition of subsidiary			0	0	0
Stock-based award activity				3	6,452
Redemption of preferred stock			(445,457)		(14,543)
Direct purchase and dividend reinvestment		1,175		2	1,173
Unrealized gains (losses) on available-for-sale securities		2,012,878				2,012,878
Reclassification adjustment for net gains (losses) included in net income (loss)		(776,734)				(776,734)
Net income (loss) attributable to Annaly		(891,163)					(891,163)
Dividends declared on preferred stock	[1]						(142,036)
Dividends and dividend equivalents declared on common stock and share-based awards		(1,285,124)					(1,285,124)	[1]
Net income (loss) attributable to noncontrolling interests		(1,391)										1,391
Equity contributions from (distributions to) noncontrolling interests												7,762
Ending balance at Dec. 31, 2020		$ 14,021,796	$ 1,536,569	$ 13,982	$ 19,750,818	$ 3,374,335	$ (10,667,388)				$ 14,008,316	$ 13,480

[1] See Note titled “Capital Stock” for dividends per share for each class of shares.