SECURITIES - Unrealized Loss Position (Details) $ in Thousands	Jun. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Unrealized Loss Position For:
Estimated Fair Value	$ 59,042,734	$ 63,655,674
Gross Unrealized Losses	(4,758,491)	(673,774)
Agency Mortgage-Backed Securities
Unrealized Loss Position For:
Estimated Fair Value	52,236,428	23,211,971
Gross Unrealized Losses	$ (4,350,328)	$ (486,024)
Number of Securities | security	2,985	590
Agency Mortgage-Backed Securities | Less than 12 months
Unrealized Loss Position For:
Estimated Fair Value	$ 43,643,601	$ 22,828,156
Gross Unrealized Losses	$ (2,950,746)	$ (475,064)
Number of Securities | security	2,712	571
Agency Mortgage-Backed Securities | 12 Months or more
Unrealized Loss Position For:
Estimated Fair Value	$ 8,592,827	$ 383,815
Gross Unrealized Losses	$ (1,399,582)	$ (10,960)
Number of Securities | security	273	19