LOANS - Summary of Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest income	$ 53,558	$ (31,963)	$ 47,107	$ (12,500)
Net income (loss) attributable to Annaly	(9,483)	167,033	453,409	(677,223)
Residential Mortgage Loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Interest income	301,820	162,202	553,836	309,432
Net gains (losses) on disposal of investments	(1,228)	(1,495)	(3,344)	(2,272)
Net unrealized gains (losses) on instruments measured at fair value through earnings	(3,913)	(167,759)	(88,698)	92,680
Net income (loss) attributable to Annaly	$ 296,679	$ (7,052)	$ 461,794	$ 399,840