DERIVATIVE INSTRUMENTS - Summary of Characteristics of Interest Rate Swaps (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Interest rate swaps, at fair value
Derivative [Line Items]
Current Notional	$ 55,097,271	$ 58,829,554
Weighted Average Pay Rate	3.20%	3.04%
Weighted Average Receive Rate	5.26%	5.31%
Weighted Average Years to Maturity	5 years 8 months 19 days	5 years 4 months 9 days
Interest rate swaps, at fair value \| Federal funds index swap
Derivative [Line Items]
Notional amount, percentage	7.00%	6.00%
Interest rate swaps, at fair value \| Secured Overnight Financing Rate
Derivative [Line Items]
Notional amount, percentage	93.00%	94.00%
Interest rate swaps, at fair value \| 0 - 3 years
Derivative [Line Items]
Minimum maturity period	0 years	0 years
Maximum maturity period	3 years	3 years
Current Notional	$ 18,093,229	$ 21,397,358
Weighted Average Pay Rate	3.53%	3.17%
Weighted Average Receive Rate	5.21%	5.26%
Weighted Average Years to Maturity	1 year 5 months 15 days	1 year 2 months 23 days
Interest rate swaps, at fair value \| 3 - 6 years
Derivative [Line Items]
Minimum maturity period	3 years	3 years
Maximum maturity period	6 years	6 years
Current Notional	$ 14,383,021	$ 12,461,799
Weighted Average Pay Rate	3.34%	3.09%
Weighted Average Receive Rate	5.31%	5.37%
Weighted Average Years to Maturity	5 years 18 days	4 years 9 months
Interest rate swaps, at fair value \| 6 - 10 years
Derivative [Line Items]
Minimum maturity period	6 years	6 years
Maximum maturity period	10 years	10 years
Current Notional	$ 20,733,537	$ 22,949,150
Weighted Average Pay Rate	2.81%	2.85%
Weighted Average Receive Rate	5.29%	5.34%
Weighted Average Years to Maturity	8 years 3 months 7 days	8 years 7 days
Interest rate swaps, at fair value \| Greater than 10 years
Derivative [Line Items]
Minimum maturity period	10 years	10 years
Current Notional	$ 1,887,484	$ 2,021,247
Weighted Average Pay Rate	3.41%	3.53%
Weighted Average Receive Rate	5.21%	5.27%
Weighted Average Years to Maturity	23 years 4 months 17 days	22 years 8 months 15 days
Forward starting pay fixed swaps
Derivative [Line Items]
Current Notional	$ 1,200,000	$ 0

Derivative instruments maximum maturity period.

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- Definition

Derivative instruments minimum maturity period.

+ References

No definition available.

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- Definition

Derivative, Nonmonetary Notional Amount, Percentage

+ References

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- Definition

Weighted average pay rate for interest rate swaps.

+ References

No definition available.

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- Definition

Weighted average receive rate for interest rate swaps.

+ References

No definition available.

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- Definition

Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480237/815-40-50-5

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1B

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-1A

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