FAIR VALUE DISCLOSURES - Fair Value Measurement Reconciliation For All Levels (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Total gains and (losses), realized and unrealized, included in:
Transfers into Level 3			$ 57	$ 11
Transfers out of Level 3			(88)	(301)
Level 3 | Corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 2,238	$ 1,914	2,070	2,103
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	2	2	4	3
Investment gains (losses), net	(1)	(8)	(2)	(11)
Subtotal	1	(6)	2	(8)
Other comprehensive income (loss)	0	(8)	10	10
Purchases	124	180	325	323
Sales	(323)	(72)	(377)	(162)
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	11	57	11
Transfers out of Level 3	0	(43)	(47)	(301)
Closing Balance	2,040	1,976	2,040	1,976
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	(8)	10	9
Level 3 | State and Political Subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	0	28	27	29
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	0	0
Investment gains (losses), net	0	0	0	0
Subtotal	0	0	0	0
Other comprehensive income (loss)	0	1	0	0
Purchases	0	0	0	0
Sales	0	(2)	0	(2)
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	(27)	0
Closing Balance	0	27	0	27
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	1	0	1
Level 3 | Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	33	12	24	0
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	0	0
Investment gains (losses), net	0	0	0	0
Subtotal	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Purchases	(6)	(12)	17	0
Sales	0	0	0	0
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	(14)	0
Closing Balance	27	0	27	0
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	0	0	0
Level 3 | CMBS
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	6	34	6	32
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	0	0
Investment gains (losses), net	0	0	0	0
Subtotal	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	2
Sales	0	0	0	0
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Closing Balance	6	34	6	34
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	0	0	0
Level 3 | Other equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	58	14	57	17
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	1	(3)
Investment gains (losses), net	0	0	0	0
Subtotal	0	0	1	(3)
Other comprehensive income (loss)	0	0	0	0
Purchases	(42)	44	0	44
Sales	39	0	(3)	0
Change in fair value of funds withheld assets	0		0
Other	0	0	0
Activity related to consolidated VIEs/VOEs	0	47	0	47
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Closing Balance	55	105	55	105
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	(3)
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	0	0	0
Level 3 | Separate Accounts Assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1	1	0	1
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	0	0
Investment gains (losses), net	0	0	0	0
Subtotal	0	0	0	0
Other comprehensive income (loss)	0	0	0	0
Purchases	(1)	0	0	0
Sales	0	0	0	0
Change in fair value of funds withheld assets	0		0
Other	0	0	0
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Closing Balance	0	1	0	1
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	0	0	0
Level 3 | Funds Withheld Payable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(29)	0	100	0
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	0	0
Investment gains (losses), net	0	(136)	0	(136)
Subtotal	0	(136)	0	(136)
Other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Change in fair value of funds withheld assets	(58)		(187)
Other	0	0	0
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Closing Balance	(87)	(136)	(87)	(136)
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	0	0	0	0
Level 3 | Modco Payable
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(292)	0	(411)	0
Total gains and (losses), realized and unrealized, included in:
Investment gains (losses), reported in net investment income	0	0	0	0
Investment gains (losses), net	0	166	0	166
Subtotal	0	166	0	166
Other comprehensive income (loss)	0	0	0	0
Purchases	0	0	0	0
Sales	0	0	0	0
Change in fair value of funds withheld assets	109		228
Other	0	0	0
Activity related to consolidated VIEs/VOEs	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Closing Balance	(183)	166	(183)	166
Change in unrealized gains or losses for the period included in earnings for instruments held at the end of the reporting period	0	0	0	0
Change in unrealized gains or losses for the period included in other comprehensive income for instruments held at the end of the reporting period	$ 0	$ 0	$ 0	$ 0