v3.24.3
Fair Value Measurements - Financial Assets and Liabilities Carried at Fair Value (Details) - USD ($)
$ in Millions
Sep. 30, 2024
Dec. 31, 2023
Financial assets at fair value:    
Equity securities $ 49 $ 51
Recurring    
Financial assets at fair value:    
Equity securities 49 51
Short-term investments 182 206
Debt Securities, including held for sale assets 9,881 9,855
Recurring | Forwards, swaps, options    
Financial assets at fair value:    
Derivative assets 129 132
Liabilities, Fair Value Disclosure [Abstract]    
Derivative liabilities 5 4
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring    
Financial assets at fair value:    
Equity securities 1 4
Short-term investments 0 0
Debt Securities, including held for sale assets 168 130
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring | Forwards, swaps, options    
Financial assets at fair value:    
Derivative assets 0 0
Liabilities, Fair Value Disclosure [Abstract]    
Derivative liabilities 0 0
Significant Other Observable Inputs (Level 2) | Recurring    
Financial assets at fair value:    
Equity securities 48 47
Short-term investments 182 206
Debt Securities, including held for sale assets 9,290 9,278
Significant Other Observable Inputs (Level 2) | Recurring | Forwards, swaps, options    
Financial assets at fair value:    
Derivative assets 129 131
Liabilities, Fair Value Disclosure [Abstract]    
Derivative liabilities 5 4
Significant Unobservable Inputs (Level 3) | Recurring    
Financial assets at fair value:    
Equity securities 0 0
Short-term investments 0 0
Debt Securities, including held for sale assets 423 447
Significant Unobservable Inputs (Level 3) | Recurring | Forwards, swaps, options    
Financial assets at fair value:    
Derivative assets 0 1
Liabilities, Fair Value Disclosure [Abstract]    
Derivative liabilities 0 0
Federal government and agency | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 289 267
Federal government and agency | Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 168 130
Federal government and agency | Significant Other Observable Inputs (Level 2) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 121 137
Federal government and agency | Significant Unobservable Inputs (Level 3) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
State and local government | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 38 38
State and local government | Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
State and local government | Significant Other Observable Inputs (Level 2) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 38 38
State and local government | Significant Unobservable Inputs (Level 3) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
Foreign government | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 376 352
Foreign government | Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
Foreign government | Significant Other Observable Inputs (Level 2) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 376 352
Foreign government | Significant Unobservable Inputs (Level 3) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
Corporate | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 8,825 8,833
Corporate | Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
Corporate | Significant Other Observable Inputs (Level 2) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 8,448 8,432
Corporate | Significant Unobservable Inputs (Level 3) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 377 401
Mortgage and other asset-backed | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 353 365
Mortgage and other asset-backed | Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 0 0
Mortgage and other asset-backed | Significant Other Observable Inputs (Level 2) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets 307 319
Mortgage and other asset-backed | Significant Unobservable Inputs (Level 3) | Recurring    
Financial assets at fair value:    
Debt Securities, including held for sale assets $ 46 $ 46