FAIR VALUE MEASUREMENTS - Fair Value Hierarchy Levels of Assets by Pricing Source, Securities Carried at Fair Value (Detail) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	$ 64,121	$ 65,269
Equity securities	887	796
Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	13,921	17,088
Equity securities	727	639
Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	46,843	46,114
Equity securities	0	0
Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	3,357	2,067
Equity securities	160	157
Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	727	639
Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	727	639
Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	24	26
Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	24	26
Broker/other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	136	131
Broker/other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Broker/other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	0	0
Broker/other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Equity securities	136	131
Government and agencies
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	14,607	17,846
Government and agencies | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	13,921	17,088
Government and agencies | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	686	758
Government and agencies | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Government and agencies | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	14,304	17,534
Government and agencies | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	13,921	17,088
Government and agencies | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	383	446
Government and agencies | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Government and agencies | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	303	312
Government and agencies | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Government and agencies | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	303	312
Government and agencies | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Municipalities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	1,930	2,034
Municipalities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Municipalities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	1,930	2,034
Municipalities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Municipalities | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	1,706	1,791
Municipalities | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Municipalities | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	1,706	1,791
Municipalities | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Municipalities | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	224	243
Municipalities | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Municipalities | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	224	243
Municipalities | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	4,366	3,563
Mortgage- and asset-backed securities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	2,072	2,407
Mortgage- and asset-backed securities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	2,294	1,156
Mortgage- and asset-backed securities | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	1,824	2,352
Mortgage- and asset-backed securities | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	1,824	2,352
Mortgage- and asset-backed securities | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	248	92
Mortgage- and asset-backed securities | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	248	55
Mortgage- and asset-backed securities | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	37
Mortgage- and asset-backed securities | Broker/other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	2,294	1,119
Mortgage- and asset-backed securities | Broker/other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities | Broker/other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Mortgage- and asset-backed securities | Broker/other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	2,294	1,119
Public utilities
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	7,174	7,045
Public utilities | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	6,298	6,398
Public utilities | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	876	647
Public utilities | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	3,660	3,628
Public utilities | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	3,660	3,628
Public utilities | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	2,638	2,770
Public utilities | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	2,638	2,770
Public utilities | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Broker/other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	876	647
Public utilities | Broker/other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Broker/other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Public utilities | Broker/other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	876	647
Sovereign and supranational
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	402	416
Sovereign and supranational | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	383	393
Sovereign and supranational | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	19	23
Sovereign and supranational | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	79	78
Sovereign and supranational | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	79	78
Sovereign and supranational | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	304	315
Sovereign and supranational | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	304	315
Sovereign and supranational | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Broker/other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	19	23
Sovereign and supranational | Broker/other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Broker/other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Sovereign and supranational | Broker/other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	19	23
Banks/financial institutions
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	9,244	8,956
Banks/financial institutions | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Banks/financial institutions | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	9,235	8,946
Banks/financial institutions | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	9	10
Banks/financial institutions | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	5,605	4,975
Banks/financial institutions | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Banks/financial institutions | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	5,605	4,975
Banks/financial institutions | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Banks/financial institutions | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	3,635	3,976
Banks/financial institutions | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Banks/financial institutions | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	3,630	3,971
Banks/financial institutions | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	5	5
Banks/financial institutions | Broker/other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	4	5
Banks/financial institutions | Broker/other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Banks/financial institutions | Broker/other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Banks/financial institutions | Broker/other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	4	5
Other corporate
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	26,398	25,409
Other corporate | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Other corporate | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	26,239	25,178
Other corporate | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	159	231
Other corporate | Third-party pricing vendor
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	21,294	20,051
Other corporate | Third-party pricing vendor | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Other corporate | Third-party pricing vendor | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	21,294	20,051
Other corporate | Third-party pricing vendor | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Other corporate | Internal
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	4,965	5,243
Other corporate | Internal | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Other corporate | Internal | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	4,945	5,127
Other corporate | Internal | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	20	116
Other corporate | Broker/other
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	139	115
Other corporate | Broker/other | Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Other corporate | Broker/other | Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	0	0
Other corporate | Broker/other | Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fixed maturity securities, available-for-sale	$ 139	$ 115