INVESTMENTS - Maturity Distribution for AFS Fixed Maturity Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Cost or Amortized Cost (Net of Allowance)
Due in One Year or Less	$ 1,484,829
Due After One Year Through Five Years	13,228,006
Due After Five Years Through Ten Years	8,101,805
Due After Ten Years	32,450,737
Subtotal	55,265,377
Cost or Amortized Cost (Net of Allowance)	84,567,549
Fair Value
Due in One Year or Less	1,471,191
Due After One Year Through Five Years	13,129,199
Due After Five Years Through Ten Years	7,882,628
Due After Ten Years	26,774,192
Subtotal	49,257,210
Fair Value	77,596,235	$ 69,414,188
Residential Mortgage-backed Securities, or “RMBS”
Cost or Amortized Cost (Net of Allowance)
Without single maturity date	11,245,083
Fair Value
Without single maturity date	10,815,026
Fair Value	10,815,026	7,946,218
Commercial Mortgage-backed Securities, or “CMBS”
Cost or Amortized Cost (Net of Allowance)
Without single maturity date	8,301,394
Fair Value
Without single maturity date	7,899,199
Fair Value	7,899,199	6,728,627
Collateralized Bond Obligations, or “CBOs”
Cost or Amortized Cost (Net of Allowance)
Without single maturity date	2,625,968
Fair Value
Without single maturity date	2,557,299
Fair Value	2,557,299	2,806,479
CLOs
Cost or Amortized Cost (Net of Allowance)
Without single maturity date	4,073,350
Fair Value
Without single maturity date	4,071,042
Fair Value	4,071,042	3,428,772
Asset-Backed Securities, or “ABSs”
Cost or Amortized Cost (Net of Allowance)
Without single maturity date	3,056,377
Fair Value
Without single maturity date	2,996,459
Fair Value	$ 2,996,459	$ 2,744,852