SECURED FINANCING - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Netted amounts	$ 52,626,503	$ 54,769,643	[1]
Repurchase agreements - weighted average remaining maturities	68 days	52 days
Repurchase agreement amount	$ 1,900,000
Remaining capacity of repurchase agreement	1,500,000
Secured financings and interest rate swaps - collateral held, estimated fair value	57,500,000	$ 59,200,000
Secured financings and interest rate swaps - collateral held, accrued interest	$ 163,000	$ 160,800

[1] (1)Derived from the audited consolidated financial statements at December 31, 2021.