NET INCOME (LOSS) PER COMMON SHARE - Schedule of Net Income (Loss) per Share Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Earnings Per Share [Abstract]
Net income (loss)	$ (8,833)	$ 161,187	$ 456,341	$ (678,141)
Net income (loss) attributable to noncontrolling interests	650	(5,846)	2,932	(918)
Net income (loss) attributable to Annaly	(9,483)	167,033	453,409	(677,223)
Dividends on preferred stock	37,158	35,766	74,219	67,641
Net income (loss) available (related) to common stockholders	$ (46,641)	$ 131,267	$ 379,190	$ (744,864)
Weighted average shares of common stock outstanding-basic (in shares)	500,950,563	494,165,256	500,781,701	491,939,177
Add: Effect of stock awards, if dilutive (in shares)	0	193,726	633,814	0
Weighted average shares of common stock outstanding-diluted (in shares)	500,950,563	494,358,982	501,415,515	491,939,177
Net income (loss) per share available (related) to common share
Basic (in dollars per share)	$ (0.09)	$ 0.27	$ 0.76	$ (1.51)
Diluted (in dollars per share)	$ (0.09)	$ 0.27	$ 0.76	$ (1.51)