FAIR VALUE MEASUREMENTS - Fair Value Measurement Inputs and Valuation Techniques (Details) $ in Millions		Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 69,801	$ 75,741
Equity securities		990	1,091
Total assets		79,159	82,924
Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		1,604	1,778
Equity securities		203	209
Total assets		1,807	1,987
Adjusted cost valuation technique | Level 3 | Private Financials
Fair Value Measurement Inputs and Valuation Techniques
Equity securities		203	209
Municipalities
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		2,141	2,320
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		2,996	2,146
Mortgage- and asset-backed securities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		680	343
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		$ 680	$ 343
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]	80.10	97.38
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]	105.93	106.71
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]	97.03	102.98
Public utilities
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 7,250	$ 7,666
Public utilities | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		259	497
Public utilities | Consensus pricing valuation technique | Level 3 | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 259
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]	93.16
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]	98.77
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]	95.08
Public utilities | Discounted cash flow technique | Level 3 | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale			$ 497
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]		0.0128
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]		0.0286
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]		0.0192
Sovereign and supranational
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 511	$ 834
Sovereign and supranational | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		31	37
Sovereign and supranational | Consensus pricing valuation technique | Level 3 | Offered Quotes
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		31	37
Banks/financial institutions
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		8,341	9,299
Banks/financial institutions | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		70	159
Banks/financial institutions | Discounted cash flow technique | Level 3 | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		70	$ 159
Banks/financial institutions | 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]		0.0067
Banks/financial institutions | 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]		0.0188
Banks/financial institutions | 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]		0.0113
Other corporate
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		26,610	$ 28,362
Other corporate | Level 3
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		564	742
Other corporate | Discounted cash flow technique | Level 3 | Credit Spreads
Fair Value Measurement Inputs and Valuation Techniques
Fixed maturity securities, available-for-sale		$ 564	$ 742
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]	0.0068	0.0066
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]	0.0512	0.0647
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]	0.0207	0.0191

[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.