NET INCOME (LOSS) PER COMMON SHARE - Schedule of Net Income (Loss) per Share Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net income (loss)	$ (839,328)	$ 2,023,894
Net income (loss) attributable to noncontrolling interests	4,928	1,639
Net income (loss) attributable to Annaly	(844,256)	2,022,255
Dividends on preferred stock	31,875	26,883
Net income (loss) available (related) to common stockholders	$ (876,131)	$ 1,995,372
Weighted average shares of common stock outstanding-basic (in shares)	489,688,364	365,340,909
Add: Effect of stock awards, if dilutive (in shares)	0	272,082
Weighted average shares of common stock outstanding-diluted (in shares)	489,688,364	365,612,991
Net income (loss) per share available (related) to common share
Basic (in dollars per share)	$ (1.79)	$ 5.46
Diluted (in dollars per share)	$ (1.79)	$ 5.46