SECURITIES - Summary of Residential Securities and CMBS (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2025 USD ($)
Debt Securities, Available-For-Sale [Roll Forward]
Beginning balance January 1, 2025	$ 69,756,447	[1],[2]
Purchases	28,964,848
Sales	(9,775,023)
Principal paydowns	(5,851,772)
(Amortization) / accretion	(122,349)
Fair value adjustment	2,090,574
Ending balance September 30, 2025	85,062,725	[2]
Agency Securities
Debt Securities, Available-For-Sale [Roll Forward]
Beginning balance January 1, 2025	67,434,068
Purchases	28,423,701
Sales	(9,340,711)
Principal paydowns	(5,185,889)
(Amortization) / accretion	(117,471)
Fair value adjustment	2,104,121
Ending balance September 30, 2025	83,317,819
Residential Credit Securities
Debt Securities, Available-For-Sale [Roll Forward]
Beginning balance January 1, 2025	2,248,101
Purchases	541,147
Sales	(392,498)
Principal paydowns	(633,432)
(Amortization) / accretion	(4,798)
Fair value adjustment	(13,614)
Ending balance September 30, 2025	1,744,906
Commercial Securities
Debt Securities, Available-For-Sale [Roll Forward]
Beginning balance January 1, 2025	74,278
Purchases	0
Sales	(41,814)
Principal paydowns	(32,451)
(Amortization) / accretion	(80)
Fair value adjustment	67
Ending balance September 30, 2025	$ 0

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

[2] (3)Excludes $2.9 billion and $2.2 billion at September 30, 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.