FINANCIAL DERIVATIVES - Schedule of Derivative Instruments in Statement of Financial Position (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2025	Dec. 31, 2024
Notional Disclosures [Abstract]
Notional Amount	$ 24,009,136	$ 24,896,331
Asset
Fair value, asset	27,867	27,789
Netting adjustments	(883)	(462)
(Liability)
Fair value, liability	(63,389)	(77,326)
Netting adjustments	883	462
Designated as hedge | Fair value hedges: | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	6,668,512	9,657,181
Asset
Fair value, asset	771	5,134
(Liability)
Fair value, liability	$ (8,174)	$ (97)
Weighted- Average Pay Rate	4.65%	2.67%
Weighted- Average Receive Rate	3.40%	4.56%
Weighted- Average Remaining Term (in years)	1 year 6 months 10 days	9 years 1 month 13 days
Designated as hedge | Fair value hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 9,777,601	$ 7,460,685
Asset
Fair value, asset	108	174
(Liability)
Fair value, liability	$ (11,160)	$ (12,165)
Weighted- Average Pay Rate	2.75%	4.71%
Weighted- Average Receive Rate	4.48%	3.40%
Weighted- Average Remaining Term (in years)	9 years 3 days	1 year 6 months 10 days
Designated as hedge | Fair value hedges: | Receive fixed callable
Notional Disclosures [Abstract]
Notional Amount	$ 4,890,883	$ 4,592,077
Asset
Fair value, asset	13,666	5,119
(Liability)
Fair value, liability	$ (44,321)	$ (65,167)
Weighted- Average Pay Rate	4.47%	4.54%
Weighted- Average Receive Rate	3.79%	3.67%
Weighted- Average Remaining Term (in years)	2 years 9 months 21 days	2 years 7 months 24 days
Designated as hedge | Cash flow hedges: | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 518,000	$ 540,000
Asset
Fair value, asset	13,602	16,903
(Liability)
Fair value, liability	$ (184)	$ (2)
Weighted- Average Pay Rate	1.90%	1.92%
Weighted- Average Receive Rate	4.83%	4.87%
Weighted- Average Remaining Term (in years)	3 years 3 months 25 days	3 years 5 months 4 days
No hedge designation | Receive fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 1,340,287	$ 1,803,328
Asset
Fair value, asset	7	48
(Liability)
Fair value, liability	$ (4)	$ (2)
Weighted- Average Pay Rate	4.44%	4.52%
Weighted- Average Receive Rate	4.26%	4.43%
Weighted- Average Remaining Term (in years)	3 months 7 days	3 months 18 days
No hedge designation | Pay fixed non-callable
Notional Disclosures [Abstract]
Notional Amount	$ 166,769	$ 157,776
Asset
Fair value, asset	588	819
(Liability)
Fair value, liability	$ (48)	$ (1)
Weighted- Average Pay Rate	2.89%	2.92%
Weighted- Average Receive Rate	4.67%	4.75%
Weighted- Average Remaining Term (in years)	3 years 2 months 15 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	7	8
(Liability)
Fair value, liability	$ (378)	$ (354)
Weighted- Average Pay Rate	4.61%	4.69%
Weighted- Average Receive Rate	4.50%	4.52%
Weighted- Average Remaining Term (in years)	3 years 8 months 1 day	3 years 9 months 29 days
No hedge designation | Treasury futures
Notional Disclosures [Abstract]
Notional Amount	$ 6,700	$ 29,900
Asset
Fair value, asset	1	46
Netting adjustments	(883)	(462)
(Liability)
Fair value, liability	(3)	0
Netting adjustments	$ 883	$ 462
Weighted- Average Forward Price (in dollars per share)	$ 111.20	$ 108.91