FINANCIAL DERIVATIVES - Schedule of Derivative Instruments in Statement of Financial Position (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Notional Disclosures [Abstract]
Notional Amount	$ 25,577,094	$ 24,896,331
Asset
Fair value, asset	44,875	27,789
Netting adjustments	(1,631)	(462)
(Liability)
Fair value, liability	(21,618)	(77,326)
Netting adjustments	1,631	462
Designated as hedge | Fair value hedges: | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	6,388,935	9,657,181
Asset
Fair value, asset	330	5,134
(Liability)
Fair value, liability	$ (2,954)	$ (97)
Weighted- Average Pay Rate	4.08%	2.67%
Weighted- Average Receive Rate	3.56%	4.56%
Weighted- Average Remaining Term (in years)	1 year 1 month 13 days	9 years 1 month 13 days
Designated as hedge | Fair value hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 10,681,418	$ 7,460,685
Asset
Fair value, asset	16,685	174
(Liability)
Fair value, liability	$ (168)	$ (12,165)
Weighted- Average Pay Rate	2.79%	4.71%
Weighted- Average Receive Rate	3.93%	3.40%
Weighted- Average Remaining Term (in years)	8 years 7 months 28 days	1 year 6 months 10 days
Designated as hedge | Fair value hedges: | Receive fixed callable
Notional Disclosures [Abstract]
Notional Amount	$ 5,446,883	$ 4,592,077
Asset
Fair value, asset	19,322	5,119
(Liability)
Fair value, liability	$ (19,911)	$ (65,167)
Weighted- Average Pay Rate	3.96%	4.54%
Weighted- Average Receive Rate	3.73%	3.67%
Weighted- Average Remaining Term (in years)	3 years 1 month 20 days	2 years 7 months 24 days
Designated as hedge | Cash flow hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 452,000	$ 540,000
Asset
Fair value, asset	9,335	16,903
(Liability)
Fair value, liability	$ (1)	$ (2)
Weighted- Average Pay Rate	1.92%	1.92%
Weighted- Average Receive Rate	4.22%	4.87%
Weighted- Average Remaining Term (in years)	3 years	3 years 5 months 4 days
No hedge designation | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 1,963,363	$ 1,803,328
Asset
Fair value, asset	66	48
(Liability)
Fair value, liability	$ (9)	$ (2)
Weighted- Average Pay Rate	3.89%	4.52%
Weighted- Average Receive Rate	3.93%	4.43%
Weighted- Average Remaining Term (in years)	3 months 10 days	3 months 18 days
No hedge designation | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 159,684	$ 157,776
Asset
Fair value, asset	613	819
(Liability)
Fair value, liability	$ (1)	$ (1)
Weighted- Average Pay Rate	2.88%	2.92%
Weighted- Average Receive Rate	4.13%	4.75%
Weighted- Average Remaining Term (in years)	3 years 7 months 9 days	3 years 4 months 24 days
No hedge designation | Basis swaps
Notional Disclosures [Abstract]
Notional Amount	$ 382,811	$ 655,384
Asset
Fair value, asset	1	8
(Liability)
Fair value, liability	$ (190)	$ (354)
Weighted- Average Pay Rate	4.13%	4.69%
Weighted- Average Receive Rate	3.89%	4.52%
Weighted- Average Remaining Term (in years)	5 years 10 days	3 years 9 months 29 days
No hedge designation | Treasury futures
Notional Disclosures [Abstract]
Notional Amount	$ 102,000	$ 29,900
Asset
Fair value, asset	154	46
Netting adjustments	(1,631)	(462)
(Liability)
Fair value, liability	(15)	0
Netting adjustments	$ 1,631	$ 462
Weighted- Average Forward Price (in dollars per share)	$ 112.57	$ 108.91