SECURITIES - Unrealized Loss Position (Details) $ in Thousands	Sep. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Unrealized Loss Position For:
Estimated Fair Value	$ 66,839,353	$ 63,655,674
Gross Unrealized Losses	(6,930,222)	(673,774)
Agency Mortgage-Backed Securities
Unrealized Loss Position For:
Estimated Fair Value	40,818,813	23,211,971
Gross Unrealized Losses	$ (5,413,016)	$ (486,024)
Number of Securities | security	2,859	590
Agency Mortgage-Backed Securities | Less than 12 months
Unrealized Loss Position For:
Estimated Fair Value	$ 38,312,990	$ 22,828,156
Gross Unrealized Losses	$ (4,825,625)	$ (475,064)
Number of Securities | security	2,722	571
Agency Mortgage-Backed Securities | 12 Months or more
Unrealized Loss Position For:
Estimated Fair Value	$ 2,505,823	$ 383,815
Gross Unrealized Losses	$ (587,391)	$ (10,960)
Number of Securities | security	137	19