LOANS - Summary of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest income	$ (31,963)	$ 475,140	$ (12,500)	$ 1,056,068
Net income (loss) attributable to Annaly	167,033	866,696	(677,223)	2,888,951
Residential Mortgage Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest income	162,202	91,645	309,432	165,110
Net gains (losses) on disposal of investments	(1,495)	(5,321)	(2,272)	(12,658)
Net unrealized gains (losses) on instruments measured at fair value through earnings	(167,759)	(324,481)	92,680	(739,729)
Net income (loss) attributable to Annaly	$ (7,052)	$ (238,157)	$ 399,840	$ (587,277)