FINANCIAL DERIVATIVES - Schedule of Derivative Instruments in Statement of Financial Position (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Notional Disclosures [Abstract]
Notional Amount	$ 24,117,672	$ 24,896,331
Asset
Fair value, asset	30,650	27,789
Netting adjustments	(2,311)	(462)
(Liability)
Fair value, liability	(53,697)	(77,326)
Netting adjustments	2,311	462
Designated as hedge | Fair value hedges: | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	6,408,185	9,657,181
Asset
Fair value, asset	2,175	5,134
(Liability)
Fair value, liability	$ (5,695)	$ (97)
Weighted- Average Pay Rate	4.68%	2.67%
Weighted- Average Receive Rate	3.43%	4.56%
Weighted- Average Remaining Term (in years)	1 year 5 months 12 days	9 years 1 month 13 days
Designated as hedge | Fair value hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 10,009,135	$ 7,460,685
Asset
Fair value, asset	136	174
(Liability)
Fair value, liability	$ (15,527)	$ (12,165)
Weighted- Average Pay Rate	2.79%	4.71%
Weighted- Average Receive Rate	4.51%	3.40%
Weighted- Average Remaining Term (in years)	8 years 9 months	1 year 6 months 10 days
Designated as hedge | Fair value hedges: | Receive fixed callable
Notional Disclosures [Abstract]
Notional Amount	$ 4,834,383	$ 4,592,077
Asset
Fair value, asset	18,655	5,119
(Liability)
Fair value, liability	$ (33,969)	$ (65,167)
Weighted- Average Pay Rate	4.52%	4.54%
Weighted- Average Receive Rate	3.75%	3.67%
Weighted- Average Remaining Term (in years)	2 years 10 months 6 days	2 years 7 months 24 days
Designated as hedge | Cash flow hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 498,000	$ 540,000
Asset
Fair value, asset	11,398	16,903
(Liability)
Fair value, liability	$ (295)	$ (2)
Weighted- Average Pay Rate	1.87%	1.92%
Weighted- Average Receive Rate	4.85%	4.87%
Weighted- Average Remaining Term (in years)	3 years 2 months 12 days	3 years 5 months 4 days
No hedge designation | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 1,563,231	$ 1,803,328
Asset
Fair value, asset	104	48
(Liability)
Fair value, liability	$ (6)	$ (2)
Weighted- Average Pay Rate	4.49%	4.52%
Weighted- Average Receive Rate	4.13%	4.43%
Weighted- Average Remaining Term (in years)	5 months 15 days	3 months 18 days
No hedge designation | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 151,854	$ 157,776
Asset
Fair value, asset	493	819
(Liability)
Fair value, liability	$ (109)	$ (1)
Weighted- Average Pay Rate	2.97%	2.92%
Weighted- Average Receive Rate	4.71%	4.75%
Weighted- Average Remaining Term (in years)	3 years 3 months 7 days	3 years 4 months 24 days
No hedge designation | Basis swaps
Notional Disclosures [Abstract]
Notional Amount	$ 640,384	$ 655,384
Asset
Fair value, asset	0	8
(Liability)
Fair value, liability	$ (386)	$ (354)
Weighted- Average Pay Rate	4.65%	4.69%
Weighted- Average Receive Rate	4.51%	4.52%
Weighted- Average Remaining Term (in years)	3 years 5 months 1 day	3 years 9 months 29 days
No hedge designation | Treasury futures
Notional Disclosures [Abstract]
Notional Amount	$ 12,500	$ 29,900
Asset
Fair value, asset	0	46
Netting adjustments	(2,311)	(462)
(Liability)
Fair value, liability	(21)	0
Netting adjustments	$ 2,311	$ 462
Weighted- Average Forward Price (in dollars per share)	$ 111.96	$ 108.91