FAIR VALUE - Schedule of Activity Under Level 3, Fair Value Measurements Using Significant Unobservable Inputs for Fixed Maturities - Available for Sale (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Transfers in/(out) of Level 3 and reclassification of securities in/(out) investment categories	$ 0		$ 0
Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain (Loss) Statement Of Income Extensible List Not Disclosed Flag	Total gains or (losses) (realized/unrealized)	Total gains or (losses) (realized/unrealized)	Total gains or (losses) (realized/unrealized)	Total gains or (losses) (realized/unrealized)
Fair Value Recurring Basis Unobservable Input Reconciliation Asset Gain (Loss) Statement Of Other Comprehensive Income Extensible List Not Disclosed Flag	Included in other comprehensive income (loss)	Included in other comprehensive income (loss)	Included in other comprehensive income (loss)	Included in other comprehensive income (loss)
Market Value
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance of fixed maturities	$ 2,045,000,000	$ 1,842,000,000	$ 1,993,000,000	$ 1,725,000,000
Total gains or (losses) (realized/unrealized) included in earnings (or changes in net assets)	(6,000,000)	1,000,000	0	3,000,000
Included in other comprehensive income (loss)	7,000,000	(3,000,000)	16,000,000	2,000,000
Purchases, issuances and settlements	37,000,000	80,000,000	73,000,000	191,000,000
Transfers in/(out) of Level 3 and reclassification of securities in/(out) investment categories	0	0	0	0
Ending balance	2,082,000,000	1,921,000,000	2,082,000,000	1,921,000,000
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	(7,000,000)	0	(3,000,000)	1,000,000
Market Value \| Corporate Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance of fixed maturities	589,000,000	711,000,000	672,000,000	715,000,000
Total gains or (losses) (realized/unrealized) included in earnings (or changes in net assets)	(7,000,000)	1,000,000	(1,000,000)	3,000,000
Included in other comprehensive income (loss)	2,000,000	0	1,000,000	(5,000,000)
Purchases, issuances and settlements	(36,000,000)	12,000,000	(123,000,000)	12,000,000
Transfers in/(out) of Level 3 and reclassification of securities in/(out) investment categories	0	0	0	0
Ending balance	549,000,000	725,000,000	549,000,000	725,000,000
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	(7,000,000)	0	(3,000,000)	1,000,000
Market Value \| Asset Backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance of fixed maturities	1,442,000,000	1,115,000,000	1,305,000,000	994,000,000
Total gains or (losses) (realized/unrealized) included in earnings (or changes in net assets)	0	0	0	0
Included in other comprehensive income (loss)	4,000,000	(3,000,000)	15,000,000	7,000,000
Purchases, issuances and settlements	73,000,000	68,000,000	199,000,000	179,000,000
Transfers in/(out) of Level 3 and reclassification of securities in/(out) investment categories	0	0	0	0
Ending balance	1,519,000,000	1,180,000,000	1,519,000,000	1,180,000,000
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	0	0	0	0
Market Value \| Foreign Corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance of fixed maturities	14,000,000	16,000,000	16,000,000	16,000,000
Total gains or (losses) (realized/unrealized) included in earnings (or changes in net assets)	0	0	1,000,000	0
Included in other comprehensive income (loss)	0	0	0	0
Purchases, issuances and settlements	0	0	(2,000,000)	0
Transfers in/(out) of Level 3 and reclassification of securities in/(out) investment categories	0	0	0	0
Ending balance	14,000,000	16,000,000	14,000,000	16,000,000
The amount of total gains or losses for the period included in earnings (or changes in net assets) attributable to the change in unrealized gains or losses relating to assets still held at the reporting date	$ 0	$ 0	$ 0	$ 0

EVEREST REINSURANCE HOLDINGS INC 10-Q