v3.25.2
Investments (Securities in a gross unrealized loss position by ratings) (Details) - USD ($)
$ in Millions
Jun. 30, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value $ 24,037 $ 27,338
Gross Unrealized Losses 2,739 3,040
U.S. Government, Government agencies and Government-sponsored enterprises    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 2,086 2,567
Gross Unrealized Losses 322 373
AAA    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 1,608 1,830
Gross Unrealized Losses 280 283
AA    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 4,234 4,257
Gross Unrealized Losses 735 730
A    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 5,901 6,340
Gross Unrealized Losses 523 582
BBB    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 9,531 11,548
Gross Unrealized Losses 787 980
Non-investment grade    
Debt Securities, Available-for-sale [Line Items]    
Estimated Fair Value 677 796
Gross Unrealized Losses $ 92 $ 92