SEGMENTS - Schedule of Segment Reporting (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023	[1]
Segment Reporting Information [Line Items]
Interest income	$ 1,177,325	$ 921,494	$ 2,271,813	$ 1,739,744
Interest expense	1,123,767	953,457	2,224,706	1,752,244
Net interest income	53,558	(31,963)	47,107	(12,500)
Servicing and related income	120,515	83,790	235,599	168,063
Servicing and related expense	12,617	8,930	24,833	16,810
Net servicing income	107,898	74,860	210,766	151,253
Other income (loss)	(113,467)	175,482	292,917	(707,841)
Less: Total general and administrative expenses	44,891	42,915	83,461	83,743
Income (loss) before income taxes	3,098	175,464	467,329	(652,831)
Income taxes	11,931	14,277	10,988	25,310
Net income (loss)	(8,833)	161,187	456,341	(678,141)
Less: Net income (loss) attributable to noncontrolling interest	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)
Unrealized gains (losses) on available-for-sale securities	(54,243)	(294,045)	(336,112)	381,329
Reclassification adjustment for net (gains) losses included in net income (loss)	179,234	462,128	514,585	945,036
Other comprehensive income (loss)	124,991	168,083	178,473	1,326,365
Comprehensive income (loss)	116,158	329,270	634,814	648,224
Comprehensive income (loss) attributable to noncontrolling interests	650	(5,846)	2,932	(918)
Comprehensive income (loss) attributable to Annaly	115,508	335,116	631,882	649,142
Receivable for unsettled trades	320,659	787,442	320,659	787,442	$ 2,710,224
Payable for unsettled trades	1,096,271	4,331,315	1,096,271	4,331,315	3,249,389
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	124,991	168,083	178,473	1,326,365
Dividends declared, not yet paid	325,662	321,031	325,662	321,031	325,052
Total assets	93,668,577	89,330,477	93,668,577	89,330,477	$ 93,227,236
Operating Segments | Agency
Segment Reporting Information [Line Items]
Interest income	821,339	694,505	1,603,265	1,301,892
Interest expense	830,324	778,480	1,677,095	1,430,164
Net interest income	(8,985)	(83,975)	(73,830)	(128,272)
Servicing and related income	0	0	0	0
Servicing and related expense	0	0	0	0
Net servicing income	0	0	0	0
Other income (loss)	(184,910)	58,225	116,042	(886,798)
Less: Total general and administrative expenses	15,862	15,685	31,450	29,825
Income (loss) before income taxes	(209,757)	(41,435)	10,762	(1,044,895)
Income taxes	118	705	725	486
Net income (loss)	(209,875)	(42,140)	10,037	(1,045,381)
Less: Net income (loss) attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to Annaly	(209,875)	(42,140)	10,037	(1,045,381)
Dividends on preferred stock	0	0	0	0
Net income (loss) available (related) to common stockholders	(209,875)	(42,140)	10,037	(1,045,381)
Unrealized gains (losses) on available-for-sale securities	(54,243)	(294,045)	(336,112)	381,329
Reclassification adjustment for net (gains) losses included in net income (loss)	179,234	462,128	514,585	945,036
Other comprehensive income (loss)	124,991	168,083	178,473	1,326,365
Comprehensive income (loss)	(84,884)	125,943	188,510	280,984
Comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to Annaly	(84,884)	125,943	188,510	280,984
Receivable for unsettled trades	311,349	780,458	311,349	780,458
Payable for unsettled trades	1,041,278	4,295,056	1,041,278	4,295,056
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	124,991	168,083	178,473	1,326,365
Dividends declared, not yet paid	0	0	0	0
Total assets	66,660,065	70,775,689	66,660,065	70,775,689
Operating Segments | Resi-credit
Segment Reporting Information [Line Items]
Interest income	353,545	218,679	662,553	419,655
Interest expense	291,816	169,239	543,678	310,740
Net interest income	61,729	49,440	118,875	108,915
Servicing and related income	0	0	0	0
Servicing and related expense	0	0	0	0
Net servicing income	0	0	0	0
Other income (loss)	48,457	66,637	153,823	104,413
Less: Total general and administrative expenses	13,148	11,884	25,822	24,562
Income (loss) before income taxes	97,038	104,193	246,876	188,766
Income taxes	(24)	673	(1,703)	8,049
Net income (loss)	97,062	103,520	248,579	180,717
Less: Net income (loss) attributable to noncontrolling interest	650	(5,846)	2,932	(918)
Net income (loss) attributable to Annaly	96,412	109,366	245,647	181,635
Dividends on preferred stock	0	0	0	0
Net income (loss) available (related) to common stockholders	96,412	109,366	245,647	181,635
Unrealized gains (losses) on available-for-sale securities	0	0	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Comprehensive income (loss)	97,062	103,520	248,579	180,717
Comprehensive income (loss) attributable to noncontrolling interests	650	(5,846)	2,932	(918)
Comprehensive income (loss) attributable to Annaly	96,412	109,366	245,647	181,635
Receivable for unsettled trades	0	4,857	0	4,857
Payable for unsettled trades	0	10	0	10
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0	0	0
Dividends declared, not yet paid	0	0	0	0
Total assets	23,462,284	15,822,726	23,462,284	15,822,726
Operating Segments | MSR
Segment Reporting Information [Line Items]
Interest income	0	0	0	0
Interest expense	0	0	0	0
Net interest income	0	0	0	0
Servicing and related income	120,515	83,790	235,599	168,063
Servicing and related expense	12,617	8,930	24,833	16,810
Net servicing income	107,898	74,860	210,766	151,253
Other income (loss)	22,324	54,950	21,454	83,184
Less: Total general and administrative expenses	8,507	7,183	17,101	14,553
Income (loss) before income taxes	121,715	122,627	215,119	219,884
Income taxes	11,920	13,089	12,069	16,848
Net income (loss)	109,795	109,538	203,050	203,036
Less: Net income (loss) attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to Annaly	109,795	109,538	203,050	203,036
Dividends on preferred stock	0	0	0	0
Net income (loss) available (related) to common stockholders	109,795	109,538	203,050	203,036
Unrealized gains (losses) on available-for-sale securities	0	0	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Comprehensive income (loss)	109,795	109,538	203,050	203,036
Comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to Annaly	109,795	109,538	203,050	203,036
Receivable for unsettled trades	9,310	1,994	9,310	1,994
Payable for unsettled trades	54,993	36,249	54,993	36,249
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0	0	0
Dividends declared, not yet paid	0	0	0	0
Total assets	3,326,780	2,252,578	3,326,780	2,252,578
Corporate & Other
Segment Reporting Information [Line Items]
Interest income	2,441	8,310	5,995	18,197
Interest expense	1,627	5,738	3,933	11,340
Net interest income	814	2,572	2,062	6,857
Servicing and related income	0	0	0	0
Servicing and related expense	0	0	0	0
Net servicing income	0	0	0	0
Other income (loss)	662	(4,330)	1,598	(8,640)
Less: Total general and administrative expenses	7,374	8,163	9,088	14,803
Income (loss) before income taxes	(5,898)	(9,921)	(5,428)	(16,586)
Income taxes	(83)	(190)	(103)	(73)
Net income (loss)	(5,815)	(9,731)	(5,325)	(16,513)
Less: Net income (loss) attributable to noncontrolling interest	0	0	0	0
Net income (loss) attributable to Annaly	(5,815)	(9,731)	(5,325)	(16,513)
Dividends on preferred stock	37,158	35,766	74,219	67,641
Net income (loss) available (related) to common stockholders	(42,973)	(45,497)	(79,544)	(84,154)
Unrealized gains (losses) on available-for-sale securities	0	0	0	0
Reclassification adjustment for net (gains) losses included in net income (loss)	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Comprehensive income (loss)	(5,815)	(9,731)	(5,325)	(16,513)
Comprehensive income (loss) attributable to noncontrolling interests	0	0	0	0
Comprehensive income (loss) attributable to Annaly	(5,815)	(9,731)	(5,325)	(16,513)
Receivable for unsettled trades	0	133	0	133
Payable for unsettled trades	0	0	0	0
Net change in unrealized gains (losses) on available-for-sale securities, net of reclassification adjustment	0	0	0	0
Dividends declared, not yet paid	325,662	321,031	325,662	321,031
Total assets	$ 219,448	$ 479,484	$ 219,448	$ 479,484

[1] (1)Derived from the audited consolidated financial statements at December 31, 2023.