INVESTMENTS - Gross Unrealized Losses (Details) $ in Thousands	Dec. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Fixed maturities
Fair value
12 months or greater	$ 2,253,146	$ 6,293,107
Less than 12 months	4,880,934	1,617,343
Total	7,134,080	7,910,450
Unrealized losses
12 months or greater	(185,909)	(453,997)
Less than 12 months	(125,426)	(26,518)
Total	$ (311,335)	$ (480,515)
Number of positions in an unrealized loss | security	3,994	3,535
Continuous unrealized loss position | security	2,108	3,212
Fixed maturities | Below Investment Grade or Not Rated
Unrealized losses
Total	$ (14,000)	$ (13,000)
U.S. government and agency
Fair value
12 months or greater	262,368	846,503
Less than 12 months	1,026,139	867,733
Total	1,288,507	1,714,236
Unrealized losses
12 months or greater	(17,515)	(42,465)
Less than 12 months	(15,621)	(12,663)
Total	(33,136)	(55,128)
Non-U.S. government
Fair value
12 months or greater	98,846	233,038
Less than 12 months	457,889	115,112
Total	556,735	348,150
Unrealized losses
12 months or greater	(9,179)	(18,178)
Less than 12 months	(16,781)	(683)
Total	(25,960)	(18,861)
Corporate debt
Fair value
12 months or greater	934,975	2,623,304
Less than 12 months	2,032,254	240,813
Total	2,967,229	2,864,117
Unrealized losses
12 months or greater	(78,979)	(210,512)
Less than 12 months	(47,245)	(5,966)
Total	(126,224)	(216,478)
Agency RMBS
Fair value
12 months or greater	280,550	778,656
Less than 12 months	749,040	218,606
Total	1,029,590	997,262
Unrealized losses
12 months or greater	(35,333)	(80,070)
Less than 12 months	(26,657)	(2,968)
Total	(61,990)	(83,038)
CMBS
Fair value
12 months or greater	410,213	703,411
Less than 12 months	260,411	75,242
Total	670,624	778,653
Unrealized losses
12 months or greater	(22,334)	(54,856)
Less than 12 months	(11,836)	(3,552)
Total	(34,170)	(58,408)
Non-agency RMBS
Fair value
12 months or greater	69,418	98,483
Less than 12 months	8,302	10,017
Total	77,720	108,500
Unrealized losses
12 months or greater	(9,900)	(13,013)
Less than 12 months	(82)	(20)
Total	(9,982)	(13,033)
ABS
Fair value
12 months or greater	147,281	879,743
Less than 12 months	295,897	83,582
Total	443,178	963,325
Unrealized losses
12 months or greater	(8,471)	(24,747)
Less than 12 months	(4,806)	(274)
Total	(13,277)	(25,021)
Municipals
Fair value
12 months or greater	49,495	129,969
Less than 12 months	51,002	6,238
Total	100,497	136,207
Unrealized losses
12 months or greater	(4,198)	(10,156)
Less than 12 months	(2,398)	(392)
Total	$ (6,596)	$ (10,548)