INVESTMENTS - Schedule of Amortized Cost, Allowance for Credit Losses, Gross Unrealized Appreciation/(Depreciation) and Fair Value of Fixed Maturity Securities (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Fixed maturity securities - available for sale
Amortized Cost	$ 16,532	$ 16,304
Allowances for Credit Losses	(46)	(48)	$ (56)	$ (46)
Unrealized Appreciation	149	212
Unrealized Depreciation	(550)	(536)
Fair Value	16,085	15,932
Fixed maturity securities - held to maturity
Amortized Cost	846	859
Allowances for Credit Loss	(9)	(8)	(9)	(9)
Unrealized Appreciation	15	12
Unrealized Depreciation	(13)	(13)
Fair Value	839	850
U.S. Treasury securities and obligations of U.S. government agencies and corporations
Fixed maturity securities - available for sale
Amortized Cost	263	265
Allowances for Credit Losses	0	0
Unrealized Appreciation	0	0
Unrealized Depreciation	(18)	(17)
Fair Value	245	247
Obligations of U.S. states and political subdivisions
Fixed maturity securities - available for sale
Amortized Cost	125	138
Allowances for Credit Losses	0	0
Unrealized Appreciation	1	1
Unrealized Depreciation	(10)	(11)
Fair Value	115	128
Corporate securities
Fixed maturity securities - available for sale
Amortized Cost	4,667	4,400
Allowances for Credit Losses	(45)	(47)	(55)	(45)
Unrealized Appreciation	67	96
Unrealized Depreciation	(157)	(160)
Fair Value	4,532	4,289
Fixed maturity securities - held to maturity
Amortized Cost	175	150
Allowances for Credit Loss	(2)	(2)	(2)	(2)
Unrealized Appreciation	5	1
Unrealized Depreciation	(4)	(3)
Fair Value	173	146
Asset-backed securities
Fixed maturity securities - available for sale
Amortized Cost	4,964	5,307
Allowances for Credit Losses	0	0
Unrealized Appreciation	25	23
Unrealized Depreciation	(29)	(48)
Fair Value	4,960	5,282
Fixed maturity securities - held to maturity
Amortized Cost	566	604
Allowances for Credit Loss	(5)	(5)	(6)	(6)
Unrealized Appreciation	4	4
Unrealized Depreciation	(9)	(10)
Fair Value	556	593
Commercial
Fixed maturity securities - available for sale
Amortized Cost	567	575
Allowances for Credit Losses	0	0
Unrealized Appreciation	0	0
Unrealized Depreciation	(49)	(53)
Fair Value	519	522
Fixed maturity securities - held to maturity
Amortized Cost	21	21
Allowances for Credit Loss	0	0
Unrealized Appreciation	0	0
Unrealized Depreciation	0	0
Fair Value	21	21
Agency residential
Fixed maturity securities - available for sale
Amortized Cost	2,512	2,532
Allowances for Credit Losses	0	0
Unrealized Appreciation	16	27
Unrealized Depreciation	(150)	(124)
Fair Value	2,377	2,435
Non-agency residential
Fixed maturity securities - available for sale
Amortized Cost	663	429
Allowances for Credit Losses	0	0
Unrealized Appreciation	8	14
Unrealized Depreciation	(4)	(1)
Fair Value	667	441
Foreign government securities
Fixed maturity securities - available for sale
Amortized Cost	963	859
Allowances for Credit Losses	0	0
Unrealized Appreciation	7	15
Unrealized Depreciation	(48)	(39)
Fair Value	922	835
Foreign corporate securities
Fixed maturity securities - available for sale
Amortized Cost	1,808	1,800
Allowances for Credit Losses	0	0	(1)	(1)
Unrealized Appreciation	25	35
Unrealized Depreciation	(85)	(82)
Fair Value	1,748	1,753
Fixed maturity securities - held to maturity
Amortized Cost	84	84
Allowances for Credit Loss	(1)	(1)	$ (1)	$ (1)
Unrealized Appreciation	6	7
Unrealized Depreciation	0	0
Fair Value	$ 89	$ 90

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of accumulated unrecognized gain on investment in debt security measured at amortized cost (held-to-maturity).

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