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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, 2024 | Dec. 31, 2023
Notional Disclosures [Abstract] |  |
Notional Amount | $ 26,094,494 | $ 25,779,468
Asset |  |
Fair value, asset | 31,433 | 37,478
Netting adjustments | (3,355) | (1,236)
(Liability) |  |
Fair value, liability | (128,530) | (117,131)
Netting adjustments | 3,355 | 1,236
Designated as hedge | Fair value hedges: | Receive fixed non-callable |  |
Notional Disclosures [Abstract] |  |
Notional Amount | 9,705,185 | 9,174,253
Asset |  |
Fair value, asset | 230 | 7,767
(Liability) |  |
Fair value, liability | $ (25,315) | $ (1,081)
Weighted- Average Pay Rate | 5.54% | 2.50%
Weighted- Average Receive Rate | 3.03% | 5.47%
Weighted- Average Remaining Term (in years) | 1 year 8 months 12 days | 9 years 6 months 25 days
Designated as hedge | Fair value hedges: | Pay fixed non-callable |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 9,226,082 | $ 9,776,685
Asset |  |
Fair value, asset | 7,675 | 2,350
(Liability) |  |
Fair value, liability | $ (68) | $ (20,390)
Weighted- Average Pay Rate | 2.52% | 5.57%
Weighted- Average Receive Rate | 5.43% | 2.94%
Weighted- Average Remaining Term (in years) | 9 years 4 months 13 days | 1 year 9 months 10 days
Designated as hedge | Fair value hedges: | Receive fixed callable |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 3,963,827 | $ 3,879,827
Asset |  |
Fair value, asset | 2,892 | 7,374
(Liability) |  |
Fair value, liability | $ (105,971) | $ (95,984)
Weighted- Average Pay Rate | 5.36% | 5.40%
Weighted- Average Receive Rate | 3.46% | 3.40%
Weighted- Average Remaining Term (in years) | 2 years 6 months 21 days | 2 years 5 months 23 days
Designated as hedge | Cash flow hedges: | Pay fixed non-callable |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 552,000 | $ 558,000
Asset |  |
Fair value, asset | 22,270 | 20,234
(Liability) |  |
Fair value, liability | $ 0 | $ (43)
Weighted- Average Pay Rate | 1.93% | 1.94%
Weighted- Average Receive Rate | 5.80% | 5.82%
Weighted- Average Remaining Term (in years) | 4 years 1 month 2 days | 4 years 3 months 18 days
No hedge designation | Receive fixed non-callable |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 1,638,958 | $ 1,358,396
Asset |  |
Fair value, asset | 34 | 263
(Liability) |  |
Fair value, liability | $ (9) | $ (3)
Weighted- Average Pay Rate | 5.38% | 5.44%
Weighted- Average Receive Rate | 5.11% | 4.87%
Weighted- Average Remaining Term (in years) | 5 months 19 days | 7 months 20 days
No hedge designation | Pay fixed non-callable |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 157,933 | $ 160,623
Asset |  |
Fair value, asset | 992 | 676
(Liability) |  |
Fair value, liability | $ 0 | $ (29)
Weighted- Average Pay Rate | 2.92% | 2.92%
Weighted- Average Receive Rate | 5.60% | 5.64%
Weighted- Average Remaining Term (in years) | 4 years 1 month 24 days | 4 years 4 months 2 days
No hedge designation | Basis swaps |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 850,384 | $ 850,384
Asset |  |
Fair value, asset | 15 | 39
(Liability) |  |
Fair value, liability | $ (522) | $ (746)
Weighted- Average Pay Rate | 5.49% | 5.52%
Weighted- Average Receive Rate | 5.47% | 5.48%
Weighted- Average Remaining Term (in years) | 3 years 6 months 29 days | 3 years 9 months 29 days
No hedge designation | Treasury futures |  |
Notional Disclosures [Abstract] |  |
Notional Amount | $ 125 | $ 21,300
Asset |  |
Fair value, asset | 680 | 11
Netting adjustments | (3,355) | (1,236)
(Liability) |  |
Fair value, liability | 0 | (91)
Netting adjustments | $ 3,355 | $ 1,236
Weighted- Average Forward Price (in dollars per share) | $ 110.25 | $ 112.51

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