SECURITIES - Portfolio (Details) - USD ($) $ in Thousands		Mar. 31, 2025	Dec. 31, 2024
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		$ 112,896,632	$ 109,210,522
Remaining Premium		2,481,106	2,471,843
Remaining Discount		(1,279,188)	(1,270,077)
Amortized Cost		71,500,103	72,059,476
Unrealized Gains		480,741	235,755
Unrealized Losses		(1,619,480)	(2,538,784)
Estimated Fair Value	[1]	70,361,364	69,756,447	[2]
Total residential securities
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		112,837,617	109,136,371
Remaining Premium		2,480,962	2,471,650
Remaining Discount		(1,279,188)	(1,270,077)
Amortized Cost		71,440,944	71,985,132
Unrealized Gains		480,741	235,717
Unrealized Losses		(1,619,382)	(2,538,680)
Estimated Fair Value		70,302,303	69,682,169
Agency
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		98,501,522	94,934,189
Remaining Premium		2,361,682	2,353,540
Remaining Discount		(1,199,184)	(1,190,316)
Amortized Cost		69,508,003	69,785,171
Unrealized Gains		416,506	155,445
Unrealized Losses		(1,594,789)	(2,506,548)
Estimated Fair Value		68,329,720	67,434,068
Agency | Fixed-rate pass-through
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		64,549,014	65,010,762
Remaining Premium		1,258,704	1,329,117
Remaining Discount		(1,191,086)	(1,178,444)
Amortized Cost		64,616,632	65,161,435
Unrealized Gains		356,094	130,742
Unrealized Losses		(1,418,833)	(2,242,503)
Estimated Fair Value		63,553,893	63,049,674
Agency | Adjustable-rate pass-through
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		137,157	157,123
Remaining Premium		8,972	11,936
Remaining Discount		(40)	(42)
Amortized Cost		146,089	169,017
Unrealized Gains		1,949	2,216
Unrealized Losses		(6,641)	(8,995)
Estimated Fair Value		141,397	162,238
Agency | CMO
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		85,886	87,467
Remaining Premium		1,418	1,459
Remaining Discount		0	0
Amortized Cost		87,304	88,926
Unrealized Gains		0	0
Unrealized Losses		(13,496)	(15,242)
Estimated Fair Value		73,808	73,684
Agency | Interest-only
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		3,757,295	3,437,570
Remaining Premium		545,553	493,803
Remaining Discount		0	0
Amortized Cost		545,553	493,803
Unrealized Gains		29,256	14,843
Unrealized Losses		(105,328)	(127,914)
Estimated Fair Value		469,481	380,732
Agency | Multifamily
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		29,947,936	26,216,351
Remaining Premium		544,756	514,726
Remaining Discount		(8,058)	(11,830)
Amortized Cost		4,085,912	3,844,575
Unrealized Gains		29,207	7,644
Unrealized Losses		(49,245)	(110,454)
Estimated Fair Value		4,065,874	3,741,765
Agency | Reverse mortgages
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		24,234	24,916
Remaining Premium		2,279	2,499
Remaining Discount		0	0
Amortized Cost		26,513	27,415
Unrealized Gains		0	0
Unrealized Losses		(1,246)	(1,440)
Estimated Fair Value		25,267	25,975
Agency | Multifamily interest-only security
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		26,400,000	22,900,000
Residential credit
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		14,336,095	14,202,182
Remaining Premium		119,280	118,110
Remaining Discount		(80,004)	(79,761)
Amortized Cost		1,932,941	2,199,961
Unrealized Gains		64,235	80,272
Unrealized Losses		(24,593)	(32,132)
Estimated Fair Value		1,972,583	2,248,101
Residential credit | Credit risk transfer
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		492,296	707,169
Remaining Premium		1,493	1,608
Remaining Discount		(3,385)	(3,581)
Amortized Cost		490,404	705,196
Unrealized Gains		30,751	49,819
Unrealized Losses		(96)	(100)
Estimated Fair Value		521,059	754,915
Residential credit | Alt-A
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		204,309	172,368
Remaining Premium		34	35
Remaining Discount		(2,062)	(1,724)
Amortized Cost		202,281	170,679
Unrealized Gains		2,969	2,694
Unrealized Losses		(7,696)	(8,481)
Estimated Fair Value		197,554	164,892
Residential credit | Prime
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		1,867,436	1,824,609
Remaining Premium		28,175	27,484
Remaining Discount		(10,084)	(10,228)
Amortized Cost		44,362	43,725
Unrealized Gains		3,035	2,732
Unrealized Losses		(700)	(667)
Estimated Fair Value		46,697	45,790
Residential credit | Subprime
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		247,047	280,820
Remaining Premium		12	12
Remaining Discount		(29,638)	(30,081)
Amortized Cost		217,421	250,751
Unrealized Gains		7,488	6,325
Unrealized Losses		(8,207)	(11,493)
Estimated Fair Value		216,702	245,583
Residential credit | NPL/RPL
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		832,022	882,547
Remaining Premium		4,304	4,540
Remaining Discount		(4,691)	(3,762)
Amortized Cost		831,635	883,325
Unrealized Gains		2,266	1,630
Unrealized Losses		(3,626)	(6,347)
Estimated Fair Value		830,275	878,608
Residential credit | Prime jumbo (>=2010 vintage)
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		10,692,985	10,334,669
Remaining Premium		85,262	84,431
Remaining Discount		(30,144)	(30,385)
Amortized Cost		146,838	146,285
Unrealized Gains		17,726	17,072
Unrealized Losses		(4,268)	(5,044)
Estimated Fair Value		160,296	158,313
Residential credit | Prime interest-only
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		1,800,000	1,800,000
Residential credit | Prime jumbo interest-only
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		10,600,000	10,200,000
Commercial Securities
Mortgage-Backed Securities Portfolio [Line Items]
Principal / Notional		59,015	74,151
Remaining Premium		144	193
Remaining Discount		0	0
Amortized Cost		59,159	74,344
Unrealized Gains		0	38
Unrealized Losses		(98)	(104)
Estimated Fair Value		$ 59,061	$ 74,278

[1] (3)Excludes $2.3 billion and $2.2 billion at March 31, 2025 and December 31, 2024, respectively, of non-Agency mortgage-backed securities in consolidated VIEs pledged as collateral and eliminated from the Company’s Consolidated Statements of Financial Condition. 

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