SEGMENTS - Schedule of Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024	[1]
Segment Reporting Information [Line Items]
Interest income	$ 1,317,108	$ 1,094,488
Interest expense	1,097,137	1,100,939
Net interest income	219,971	(6,451)
Servicing and related income	140,435	115,084
Servicing and related expense	14,113	12,216
Net servicing income	126,322	102,868
Other income (loss)	(159,657)	406,384
Less: Total general and administrative expenses	48,064	38,570
Income (loss) before income taxes	138,572	464,231
Income taxes	8,267	(943)
Net income (loss)	130,305	465,174
Less: Net income (loss) attributable to noncontrolling interest	6,081	2,282
Net income (loss) attributable to Annaly	124,224	462,892
Dividends on preferred stock	37,157	37,061
Net income (loss) available (related) to common stockholders	87,067	425,831
Unrealized gains (losses) on available-for-sale securities	164,877	(281,869)
Reclassification adjustment for net (gains) losses included in net income (loss)	65,403	335,351
Other comprehensive income (loss)	230,280	53,482
Comprehensive income (loss)	360,585	518,656
Comprehensive income (loss) attributable to noncontrolling interests	6,081	2,282
Comprehensive income (loss) attributable to Annaly	354,504	516,374
Receivable for unsettled trades	2,523	941,366	$ 2,201,447
Payable for unsettled trades	2,304,774	2,556,798	308,282
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	230,280	53,482
Dividends declared, not yet paid	421,637	325,286	375,932
Total assets	105,115,346	91,483,546	$ 103,556,384
Operating Segments | Agency
Segment Reporting Information [Line Items]
Interest income	849,200	781,926
Interest expense	718,253	846,771
Net interest income	130,947	(64,845)
Servicing and related income	0	0
Servicing and related expense	0	0
Net servicing income	0	0
Other income (loss)	(166,925)	300,952
Less: Total general and administrative expenses	17,316	15,588
Income (loss) before income taxes	(53,294)	220,519
Income taxes	290	607
Net income (loss)	(53,584)	219,912
Less: Net income (loss) attributable to noncontrolling interest	0	0
Net income (loss) attributable to Annaly	(53,584)	219,912
Dividends on preferred stock	0	0
Net income (loss) available (related) to common stockholders	(53,584)	219,912
Unrealized gains (losses) on available-for-sale securities	164,877	(281,869)
Reclassification adjustment for net (gains) losses included in net income (loss)	65,403	335,351
Other comprehensive income (loss)	230,280	53,482
Comprehensive income (loss)	176,696	273,394
Comprehensive income (loss) attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Annaly	176,696	273,394
Receivable for unsettled trades	2,306	907,634
Payable for unsettled trades	2,220,276	2,430,956
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	230,280	53,482
Dividends declared, not yet paid	0	0
Total assets	70,429,198	66,485,685
Operating Segments | Resi-credit
Segment Reporting Information [Line Items]
Interest income	466,853	309,008
Interest expense	378,174	251,862
Net interest income	88,679	57,146
Servicing and related income	0	0
Servicing and related expense	0	0
Net servicing income	0	0
Other income (loss)	12,090	105,366
Less: Total general and administrative expenses	15,506	12,674
Income (loss) before income taxes	85,263	149,838
Income taxes	(524)	(1,679)
Net income (loss)	85,787	151,517
Less: Net income (loss) attributable to noncontrolling interest	6,081	2,282
Net income (loss) attributable to Annaly	79,706	149,235
Dividends on preferred stock	0	0
Net income (loss) available (related) to common stockholders	79,706	149,235
Unrealized gains (losses) on available-for-sale securities	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0
Other comprehensive income (loss)	0	0
Comprehensive income (loss)	85,787	151,517
Comprehensive income (loss) attributable to noncontrolling interests	6,081	2,282
Comprehensive income (loss) attributable to Annaly	79,706	149,235
Receivable for unsettled trades	0	5,000
Payable for unsettled trades	0	0
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0
Dividends declared, not yet paid	0	0
Total assets	30,678,639	21,525,612
Operating Segments | MSR
Segment Reporting Information [Line Items]
Interest income	0	0
Interest expense	0	0
Net interest income	0	0
Servicing and related income	140,435	115,084
Servicing and related expense	14,113	12,216
Net servicing income	126,322	102,868
Other income (loss)	(2,961)	(870)
Less: Total general and administrative expenses	9,393	8,594
Income (loss) before income taxes	113,968	93,404
Income taxes	8,510	149
Net income (loss)	105,458	93,255
Less: Net income (loss) attributable to noncontrolling interest	0	0
Net income (loss) attributable to Annaly	105,458	93,255
Dividends on preferred stock	0	0
Net income (loss) available (related) to common stockholders	105,458	93,255
Unrealized gains (losses) on available-for-sale securities	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0
Other comprehensive income (loss)	0	0
Comprehensive income (loss)	105,458	93,255
Comprehensive income (loss) attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Annaly	105,458	93,255
Receivable for unsettled trades	217	28,732
Payable for unsettled trades	84,498	125,842
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0
Dividends declared, not yet paid	0	0
Total assets	3,849,181	3,209,074
Corporate & Other
Segment Reporting Information [Line Items]
Interest income	1,055	3,554
Interest expense	710	2,306
Net interest income	345	1,248
Servicing and related income	0	0
Servicing and related expense	0	0
Net servicing income	0	0
Other income (loss)	(1,861)	936
Less: Total general and administrative expenses	5,849	1,714
Income (loss) before income taxes	(7,365)	470
Income taxes	(9)	(20)
Net income (loss)	(7,356)	490
Less: Net income (loss) attributable to noncontrolling interest	0	0
Net income (loss) attributable to Annaly	(7,356)	490
Dividends on preferred stock	37,157	37,061
Net income (loss) available (related) to common stockholders	(44,513)	(36,571)
Unrealized gains (losses) on available-for-sale securities	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0
Other comprehensive income (loss)	0	0
Comprehensive income (loss)	(7,356)	490
Comprehensive income (loss) attributable to noncontrolling interests	0	0
Comprehensive income (loss) attributable to Annaly	(7,356)	490
Receivable for unsettled trades	0	0
Payable for unsettled trades	0	0
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0
Dividends declared, not yet paid	421,637	325,286
Total assets	$ 158,328	$ 263,175

[1] (1)Derived from the audited consolidated financial statements at December 31, 2024.