SECURED FINANCING - Repurchase Agreements - Remaining Maturities, Collateral Types and Weighted Average Rate (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Repurchase Agreements:
Gross amounts	$ 66,989,156	$ 64,469,836
Amounts offset	(2,678,880)	(2,268,293)
Net amounts of Repurchase agreements as presented in the Consolidated Statements of Financial Condition.	$ 64,310,276	$ 62,201,543	[1]
Repurchase agreements, remaining maturities, percentage	1.00%	0.00%
CRTs
Repurchase Agreements:
Gross amounts	$ 641,403	$ 695,520
Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	2,536,370	2,157,763
Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	1,267,207	851,851
Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	62,448,885	60,573,426
Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	95,291	191,276
1 day
Repurchase Agreements:
Gross amounts	25,215,457	0
1 day | CRTs
Repurchase Agreements:
Gross amounts	175,637	0
1 day | Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	41,503	0
1 day | Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	0	0
1 day | Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	24,998,317	0
1 day | Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	0	0
2 to 29 days
Repurchase Agreements:
Gross amounts	2,094,734	35,080,196
2 to 29 days | CRTs
Repurchase Agreements:
Gross amounts	275,927	555,568
2 to 29 days | Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	846,860	840,400
2 to 29 days | Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	221,231	0
2 to 29 days | Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	655,425	33,492,952
2 to 29 days | Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	95,291	191,276
30 to 59 days
Repurchase Agreements:
Gross amounts	34,814,805	18,618,606
30 to 59 days | CRTs
Repurchase Agreements:
Gross amounts	0	0
30 to 59 days | Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	589,802	528,341
30 to 59 days | Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	26,404	0
30 to 59 days | Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	34,198,599	18,090,265
30 to 59 days | Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	0	0
60 to 89 days
Repurchase Agreements:
Gross amounts	3,801,389	7,198,769
60 to 89 days | CRTs
Repurchase Agreements:
Gross amounts	142,486	139,952
60 to 89 days | Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	611,235	579,611
60 to 89 days | Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	452,799	0
60 to 89 days | Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	2,594,869	6,479,206
60 to 89 days | Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	0	0
90 to 119 days
Repurchase Agreements:
Gross amounts	131,078	247,306
90 to 119 days | CRTs
Repurchase Agreements:
Gross amounts	47,353	0
90 to 119 days | Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	82,050	39,714
90 to 119 days | Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	0	207,592
90 to 119 days | Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	1,675	0
90 to 119 days | Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	0	0
Over 119 days
Repurchase Agreements:
Gross amounts	931,693	3,324,959
Over 119 days | CRTs
Repurchase Agreements:
Gross amounts	0	0
Over 119 days | Non-Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	364,920	169,697
Over 119 days | Residential Mortgage Loans
Repurchase Agreements:
Gross amounts	566,773	644,259
Over 119 days | Agency Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	0	2,511,003
Over 119 days | Commercial Mortgage-Backed Securities
Repurchase Agreements:
Gross amounts	$ 0	$ 0

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