FAIR VALUE MEASUREMENTS - Fair Value Measurement Inputs and Valuation Techniques (Details) $ in Millions		Sep. 30, 2024 USD ($)	Dec. 31, 2023 USD ($)
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 72,292	$ 73,290
Equity securities		808	1,088
Total assets		82,444	80,325
Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		2,191	1,781
Equity securities		161	248
Total assets		2,352	2,029
Adjusted cost valuation technique | Level 3 | Private Financials
Fair Value Measurement Inputs and Valuation Techniques
Equity securities		161	248
Municipalities
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		2,230	2,298
Municipalities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		0	0
Mortgage- and asset-backed securities
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		3,730	3,086
Mortgage- and asset-backed securities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		1,209	772
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3 | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 1,209	$ 772
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3 | Lower Limit | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[1]	85.75	84.81
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3 | Upper Limit | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[1]	109.00	105.89
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3 | Weighted Average | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[1]	100.74	99.39
Public utilities
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 7,474	$ 7,592
Public utilities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		570	253
Public utilities | Consensus pricing valuation technique | Level 3 | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale			$ 253
Public utilities | Consensus pricing valuation technique | Level 3 | Lower Limit | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[1]		94.34
Public utilities | Consensus pricing valuation technique | Level 3 | Upper Limit | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[1]		102.99
Public utilities | Consensus pricing valuation technique | Level 3 | Weighted Average | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[1]		96.46
Public utilities | Discounted cash flow technique | Level 3 | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 570
Public utilities | Discounted cash flow technique | Level 3 | Lower Limit | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[2]	0.0175
Public utilities | Discounted cash flow technique | Level 3 | Upper Limit | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[2]	0.0375
Public utilities | Discounted cash flow technique | Level 3 | Weighted Average | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[2]	0.0216
Sovereign and supranational
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 494	$ 537
Sovereign and supranational | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		28	30
Sovereign and supranational | Consensus pricing valuation technique | Level 3 | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		28	30
Banks/financial institutions
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		9,760	8,835
Banks/financial institutions | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		10	78
Banks/financial institutions | Discounted cash flow technique | Level 3 | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		10	78
Other corporate
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		27,663	28,342
Other corporate | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		374	648
Other corporate | Discounted cash flow technique | Level 3 | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 374	$ 648
Other corporate | Discounted cash flow technique | Level 3 | Lower Limit | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[2]	0.0090	0.0069
Other corporate | Discounted cash flow technique | Level 3 | Upper Limit | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[2]	0.0294	0.0423
Other corporate | Discounted cash flow technique | Level 3 | Weighted Average | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale, measurement input	[2]	0.0211	0.0206

[1] Represents prices for securities where the Company receives unadjusted broker quotes and for which there is no transparency into the providers' valuation techniques.

[2] Actual or equivalent credit spreads in basis points.