FINANCIAL DERIVATIVES - Schedule of Derivative Instruments in Statement of Financial Position (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Notional Disclosures [Abstract]
Notional Amount	$ 25,779,468	$ 23,878,611
Asset
Fair value, asset	37,478	37,409
Netting adjustments	(1,236)	(5,212)
(Liability)
Fair value, liability	(117,131)	(175,326)
Netting adjustments	1,236	5,212
Designated as hedge | Fair value hedges: | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	9,776,685	8,149,871
Asset
Fair value, asset	2,350	13,689
(Liability)
Fair value, liability	$ (20,390)	$ (366)
Weighted- Average Pay Rate	5.57%	2.23%
Weighted- Average Receive Rate	2.94%	4.33%
Weighted- Average Remaining Term (in years)	1 year 9 months 10 days	10 years 9 months 3 days
Designated as hedge | Fair value hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 9,174,253	$ 10,033,750
Asset
Fair value, asset	7,767	19
(Liability)
Fair value, liability	$ (1,081)	$ (4,686)
Weighted- Average Pay Rate	2.50%	4.31%
Weighted- Average Receive Rate	5.47%	2.03%
Weighted- Average Remaining Term (in years)	9 years 6 months 25 days	1 year 7 months 20 days
Designated as hedge | Fair value hedges: | Receive fixed callable
Notional Disclosures [Abstract]
Notional Amount	$ 3,879,827	$ 2,764,577
Asset
Fair value, asset	7,374	461
(Liability)
Fair value, liability	$ (95,984)	$ (174,757)
Weighted- Average Pay Rate	5.40%	4.21%
Weighted- Average Receive Rate	3.40%	1.98%
Weighted- Average Remaining Term (in years)	2 years 5 months 23 days	3 years 2 months 4 days
Designated as hedge | Cash flow hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 558,000	$ 588,000
Asset
Fair value, asset	20,234	27,275
(Liability)
Fair value, liability	$ (43)	$ 0
Weighted- Average Pay Rate	1.94%	1.93%
Weighted- Average Receive Rate	5.82%	4.72%
Weighted- Average Remaining Term (in years)	4 years 3 months 18 days	5 years 18 days
No hedge designation | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 1,358,396	$ 287,750
Asset
Fair value, asset	263	0
(Liability)
Fair value, liability	$ (3)	$ (130)
Weighted- Average Pay Rate	5.44%	4.31%
Weighted- Average Receive Rate	4.87%	1.16%
Weighted- Average Remaining Term (in years)	7 months 20 days	1 year 9 months 3 days
No hedge designation | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 160,623	$ 187,479
Asset
Fair value, asset	676	1,065
(Liability)
Fair value, liability	$ (29)	$ (1)
Weighted- Average Pay Rate	2.92%	3.05%
Weighted- Average Receive Rate	5.64%	4.09%
Weighted- Average Remaining Term (in years)	4 years 4 months 2 days	4 years 6 months 7 days
No hedge designation | Basis swaps
Notional Disclosures [Abstract]
Notional Amount	$ 850,384	$ 1,860,384
Asset
Fair value, asset	39	112
(Liability)
Fair value, liability	$ (746)	$ (456)
Weighted- Average Pay Rate	5.52%	4.40%
Weighted- Average Receive Rate	5.48%	4.42%
Weighted- Average Remaining Term (in years)	3 years 9 months 29 days	2 years 5 months 15 days
No hedge designation | Treasury futures
Notional Disclosures [Abstract]
Notional Amount	$ 21,300	$ 6,800
Asset
Fair value, asset	11	0
Netting adjustments	(1,236)	(5,212)
(Liability)
Fair value, liability	(91)	(142)
Netting adjustments	$ 1,236	$ 5,212
Weighted- Average Forward Price (in dollars per share)	$ 112.51	$ 114.38