FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets by Pricing Source, Securities Carried at Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	$ 98,696	$ 105,882
Equity securities	1,603	1,283
Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	32,532	36,032
Equity securities	1,340	1,095
Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	64,866	68,833
Equity securities	90	86
Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	1,298	1,017
Equity securities	173	102
Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	1,430	1,181
Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	1,340	1,095
Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	90	86
Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Net asset value valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	173	102
Net asset value valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Net asset value valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Net asset value valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	173	102
Government and agencies
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	33,820	37,350
Government and agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	32,532	36,032
Government and agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	1,288	1,318
Government and agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Government and agencies | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	33,340	37,350
Government and agencies | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	32,532	36,032
Government and agencies | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	808	1,318
Government and agencies | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Government and agencies | Internal valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	480
Government and agencies | Internal valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Government and agencies | Internal valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	480
Government and agencies | Internal valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Municipalities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	3,036	3,018
Municipalities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	3,036	3,018
Municipalities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	2,222	3,018
Municipalities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	2,222	3,018
Municipalities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Municipalities | Internal valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	814
Municipalities | Internal valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Municipalities | Internal valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	814
Municipalities | Internal valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Mortgage- and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	1,246	1,038
Mortgage- and asset-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	955	814
Mortgage- and asset-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	291	224
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	955	364
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	955	364
Mortgage- and asset-backed securities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	291	674
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	450
Mortgage- and asset-backed securities | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	291	224
Public utilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	10,051	10,817
Public utilities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	9,558	10,395
Public utilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	493	422
Public utilities | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	4,527	10,395
Public utilities | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	4,527	10,395
Public utilities | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Discounted cash flow technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	493	422
Public utilities | Discounted cash flow technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Discounted cash flow technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Public utilities | Discounted cash flow technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	493	422
Public utilities | Internal valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	5,031
Public utilities | Internal valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Public utilities | Internal valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	5,031
Public utilities | Internal valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Sovereign and supranational
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	1,115	1,382
Sovereign and supranational | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Sovereign and supranational | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	1,072	1,334
Sovereign and supranational | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	43	48
Sovereign and supranational | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	273	1,334
Sovereign and supranational | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Sovereign and supranational | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	273	1,334
Sovereign and supranational | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Sovereign and supranational | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities		48
Sovereign and supranational | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities		0
Sovereign and supranational | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities		0
Sovereign and supranational | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities		48
Sovereign and supranational | Discounted cash flow technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	43
Sovereign and supranational | Discounted cash flow technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Sovereign and supranational | Discounted cash flow technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Sovereign and supranational | Discounted cash flow technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	43	48
Sovereign and supranational | Internal valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	799
Sovereign and supranational | Internal valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Sovereign and supranational | Internal valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	799
Sovereign and supranational | Internal valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Banks/financial institutions
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	11,591	12,060
Banks/financial institutions | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	11,546	12,036
Banks/financial institutions | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	45	24
Banks/financial institutions | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	5,237	12,036
Banks/financial institutions | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	5,237	12,036
Banks/financial institutions | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Consensus pricing valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	45	24
Banks/financial institutions | Consensus pricing valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Consensus pricing valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Banks/financial institutions | Consensus pricing valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	45	24
Banks/financial institutions | Internal valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	6,309
Banks/financial institutions | Internal valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Banks/financial institutions | Internal valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	6,309
Banks/financial institutions | Internal valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Other corporate
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	37,837	40,217
Other corporate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	37,411	39,918
Other corporate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	426	299
Other corporate | Third party pricing vendor valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	29,495	39,886
Other corporate | Third party pricing vendor valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Third party pricing vendor valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	29,495	39,886
Other corporate | Third party pricing vendor valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Discounted cash flow technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	426	331
Other corporate | Discounted cash flow technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	0
Other corporate | Discounted cash flow technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0	32
Other corporate | Discounted cash flow technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	426	$ 299
Other corporate | Internal valuation technique
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	7,916
Other corporate | Internal valuation technique | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	0
Other corporate | Internal valuation technique | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	7,916
Other corporate | Internal valuation technique | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Available for sale, fixed maturity securities	$ 0