SEGMENTS - Schedule of Segment Reporting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Interest income	$ 4,840,034	$ 3,731,581	$ 2,778,887
Interest expense	4,592,238	3,842,965	1,309,735
Net interest income	247,796	(111,384)	1,469,152
Servicing and related income	485,406	364,157	246,926
Servicing and related expense	49,469	37,652	25,145
Net servicing income	435,937	326,505	221,781
Other income (loss)	514,651	(1,651,591)	243,787
Total general and administrative expenses	171,356	162,553	162,729
Income (loss) before income taxes	1,027,028	(1,599,023)	1,771,991
Income taxes	15,260	39,434	45,571
Net income (loss)	1,011,768	(1,638,457)	1,726,420
Net income (loss) attributable to noncontrolling interests	9,862	4,714	1,095
Net income (loss) attributable to Annaly	1,001,906	(1,643,171)	1,725,325
Dividends on preferred stock	154,551	141,676	110,623
Net income (loss) available (related) to common stockholders	847,355	(1,784,847)	1,614,702
Unrealized gains (losses) on available-for-sale securities	(244,278)	580,680	(8,204,542)
Reclassification adjustment for net (gains) losses included in net income (loss)	561,996	1,792,816	3,537,236
Other comprehensive income (loss)	317,718	2,373,496	(4,667,306)
Comprehensive income (loss)	1,329,486	735,039	(2,940,886)
Comprehensive income (loss) attributable to noncontrolling interests	9,862	4,714	1,095
Comprehensive income (loss) attributable to Annaly	1,319,624	730,325	(2,941,981)
Receivable for unsettled trades	2,201,447	2,710,224	575,091
Payable for unsettled trades	308,282	3,249,389	1,157,846
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	317,718	2,373,496	(4,667,306)
Dividends declared, not yet paid	375,932	325,052	412,113
Total assets	103,556,384	93,227,236	81,850,712
Operating Segments | Agency
Segment Reporting Information [Line Items]
Interest income	3,340,101	2,772,963	2,146,583
Interest expense	3,367,984	3,096,245	936,063
Net interest income	(27,883)	(323,282)	1,210,520
Servicing and related income	0	0	0
Servicing and related expense	0	0	0
Net servicing income	0	0	0
Other income (loss)	381,691	(1,824,323)	480,383
Total general and administrative expenses	63,854	58,852	50,817
Income (loss) before income taxes	289,954	(2,206,457)	1,640,086
Income taxes	2,026	1,629	(792)
Net income (loss)	287,928	(2,208,086)	1,640,878
Net income (loss) attributable to noncontrolling interests	0	0	0
Net income (loss) attributable to Annaly	287,928	(2,208,086)	1,640,878
Dividends on preferred stock	0	0	0
Net income (loss) available (related) to common stockholders	287,928	(2,208,086)	1,640,878
Unrealized gains (losses) on available-for-sale securities	(244,278)	580,680	(8,204,542)
Reclassification adjustment for net (gains) losses included in net income (loss)	561,996	1,792,816	3,537,236
Other comprehensive income (loss)	317,718	2,373,496	(4,667,306)
Comprehensive income (loss)	605,646	165,410	(3,026,428)
Comprehensive income (loss) attributable to noncontrolling interests	0	0	0
Comprehensive income (loss) attributable to Annaly	605,646	165,410	(3,026,428)
Receivable for unsettled trades	2,142,357	2,709,398	572,089
Payable for unsettled trades	280,515	3,232,941	1,108,386
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	317,718	2,373,496	(4,667,306)
Dividends declared, not yet paid	0	0	0
Total assets	71,834,543	71,167,416	65,080,130
Operating Segments | Residential Credit
Segment Reporting Information [Line Items]
Interest income	1,490,076	930,232	550,449
Interest expense	1,217,780	728,273	344,669
Net interest income	272,296	201,959	205,780
Servicing and related income	0	0	0
Servicing and related expense	0	0	0
Net servicing income	0	0	0
Other income (loss)	147,449	171,678	(147,908)
Total general and administrative expenses	53,408	49,021	47,005
Income (loss) before income taxes	366,337	324,616	10,867
Income taxes	(15,705)	17,121	(10,485)
Net income (loss)	382,042	307,495	21,352
Net income (loss) attributable to noncontrolling interests	9,862	4,714	1,088
Net income (loss) attributable to Annaly	372,180	302,781	20,264
Dividends on preferred stock	0	0	0
Net income (loss) available (related) to common stockholders	372,180	302,781	20,264
Unrealized gains (losses) on available-for-sale securities	0	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0	0
Other comprehensive income (loss)	0	0	0
Comprehensive income (loss)	382,042	307,495	21,352
Comprehensive income (loss) attributable to noncontrolling interests	9,862	4,714	1,088
Comprehensive income (loss) attributable to Annaly	372,180	302,781	20,264
Receivable for unsettled trades	0	0	0
Payable for unsettled trades	0	10	38
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0	0
Dividends declared, not yet paid	0	0	0
Total assets	28,137,561	19,149,003	14,152,927
Operating Segments | MSR
Segment Reporting Information [Line Items]
Interest income	0	0	0
Interest expense	0	0	6,202
Net interest income	0	0	(6,202)
Servicing and related income	485,406	364,157	246,926
Servicing and related expense	49,469	37,652	25,145
Net servicing income	435,937	326,505	221,781
Other income (loss)	(19,330)	13,975	(47,510)
Total general and administrative expenses	34,670	29,872	29,784
Income (loss) before income taxes	381,937	310,608	138,285
Income taxes	29,108	21,070	57,055
Net income (loss)	352,829	289,538	81,230
Net income (loss) attributable to noncontrolling interests	0	0	0
Net income (loss) attributable to Annaly	352,829	289,538	81,230
Dividends on preferred stock	0	0	0
Net income (loss) available (related) to common stockholders	352,829	289,538	81,230
Unrealized gains (losses) on available-for-sale securities	0	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0	0
Other comprehensive income (loss)	0	0	0
Comprehensive income (loss)	352,829	289,538	81,230
Comprehensive income (loss) attributable to noncontrolling interests	0	0	0
Comprehensive income (loss) attributable to Annaly	352,829	289,538	81,230
Receivable for unsettled trades	59,090	826	3,002
Payable for unsettled trades	27,767	16,438	49,422
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0	0
Dividends declared, not yet paid	0	0	0
Total assets	3,406,686	2,578,644	1,931,176
Corporate & Other
Segment Reporting Information [Line Items]
Interest income	9,857	28,386	81,855
Interest expense	6,474	18,447	22,801
Net interest income	3,383	9,939	59,054
Servicing and related income	0	0	0
Servicing and related expense	0	0	0
Net servicing income	0	0	0
Other income (loss)	4,841	(12,921)	(41,178)
Total general and administrative expenses	19,424	24,808	35,123
Income (loss) before income taxes	(11,200)	(27,790)	(17,247)
Income taxes	(169)	(386)	(207)
Net income (loss)	(11,031)	(27,404)	(17,040)
Net income (loss) attributable to noncontrolling interests	0	0	7
Net income (loss) attributable to Annaly	(11,031)	(27,404)	(17,047)
Dividends on preferred stock	154,551	141,676	110,623
Net income (loss) available (related) to common stockholders	(165,582)	(169,080)	(127,670)
Unrealized gains (losses) on available-for-sale securities	0	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0	0
Other comprehensive income (loss)	0	0	0
Comprehensive income (loss)	(11,031)	(27,404)	(17,040)
Comprehensive income (loss) attributable to noncontrolling interests	0	0	7
Comprehensive income (loss) attributable to Annaly	(11,031)	(27,404)	(17,047)
Receivable for unsettled trades	0	0	0
Payable for unsettled trades	0	0	0
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0	0
Dividends declared, not yet paid	375,932	325,052	412,113
Total assets	$ 177,594	$ 332,173	$ 686,479