MORTGAGE-BACKED SECURITIES - Sales (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Marketable Securities, Gain (Loss)
Investment Sales, Carrying Value	$ 2,857,250,000	$ 4,225,522,000	$ 3,332,083,000
Proceeds From Sale Of Mortgage Backed Securities MBS Categorized As Trading	2,851,708,000	4,200,536,000	3,321,206,000
Marketable Securities, Realized Gain (Loss)	(5,542,000)	(24,986,000)	(10,877,000)
Available For Sale Securities Gross Realized Gains	7,930,000	8,678,000	2,177,000
Available For Sale Securities Gross Realized Losses	$ 13,472,000	$ 33,664,000	$ 13,054,000