v3.26.1
FAIR VALUE - Schedule of Fair Value Measurement Levels for all Assets and Liabilities (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value $ 34,651 $ 34,573
Equity securities, fair value 177 180
Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Equity securities, fair value 89 88
Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 32,084 32,099
Equity securities, fair value 89 92
Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 2,568 2,474
Equity securities, fair value 0 0
U.S. Treasury securities and obligations of U.S. government agencies and corporations    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 874 830
U.S. Treasury securities and obligations of U.S. government agencies and corporations | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
U.S. Treasury securities and obligations of U.S. government agencies and corporations | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 874 830
U.S. Treasury securities and obligations of U.S. government agencies and corporations | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Obligations of U.S. States and political subdivisions    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 40 41
Obligations of U.S. States and political subdivisions | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Obligations of U.S. States and political subdivisions | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 40 41
Obligations of U.S. States and political subdivisions | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Corporate securities    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 9,843 9,882
Corporate securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Corporate securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 9,479 9,512
Corporate securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 364 370
Asset-backed securities    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 4,898 5,077
Asset-backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Asset-backed securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 2,708 2,987
Asset-backed securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 2,190 2,091
Agency commercial    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 408 412
Agency commercial | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Agency commercial | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 408 412
Agency commercial | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Non-agency commercial    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 1,215 1,121
Non-agency commercial | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Non-agency commercial | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 1,215 1,121
Non-agency commercial | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Agency residential    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 5,309 5,465
Agency residential | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Agency residential | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 5,309 5,465
Agency residential | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Non-agency residential    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 1,783 1,721
Non-agency residential | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Non-agency residential | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 1,783 1,721
Non-agency residential | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Foreign government securities    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 2,311 2,371
Foreign government securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Foreign government securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 2,311 2,371
Foreign government securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Foreign corporate securities    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 7,970 7,653
Foreign corporate securities | Quoted Prices in Active Markets for Identical Assets (Level 1)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 0 0
Foreign corporate securities | Significant Other Observable Inputs (Level 2)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value 7,957 7,639
Foreign corporate securities | Significant Unobservable Inputs (Level 3)    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value $ 14 $ 14