v3.25.2
Reportable Segments - Schedule of Reportable Segments Revenue Information (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Segment Reporting Information        
Net investment income $ 754 $ 712 $ 1,608 $ 1,476
Net gains (losses) on investments and derivatives (144) (103) (493) (267)
Total revenues 16,633 15,714 33,085 30,973
Operating segments | Property-Liability        
Segment Reporting Information        
Insurance premiums 14,346 13,339 28,373 26,239
Other revenue 504 441 992 871
Net investment income 687 643 1,470 1,345
Net gains (losses) on investments and derivatives (190) (103) (519) (265)
Total revenues 15,347 14,320 30,316 28,190
Operating segments | Property-Liability | Allstate Protection        
Segment Reporting Information        
Insurance premiums 14,346 13,339 28,373 26,239
Operating segments | Property-Liability | Run-off Property-Liability        
Segment Reporting Information        
Insurance premiums 0 0 0 0
Operating segments | Property-Liability | Auto | Allstate Protection        
Segment Reporting Information        
Insurance premiums 9,528 9,079 18,875 17,857
Operating segments | Property-Liability | Homeowners | Allstate Protection        
Segment Reporting Information        
Insurance premiums 3,771 3,255 7,428 6,409
Operating segments | Property-Liability | Other personal lines | Allstate Protection        
Segment Reporting Information        
Insurance premiums 779 701 1,520 1,360
Operating segments | Property-Liability | Commercial lines | Allstate Protection        
Segment Reporting Information        
Insurance premiums 104 158 217 327
Operating segments | Property-Liability | Other business lines | Allstate Protection        
Segment Reporting Information        
Insurance premiums 164 146 333 286
Operating segments | Protection Services        
Segment Reporting Information        
Intersegment premiums and service fees 36 39 73 74
Other revenue 111 98 239 183
Net investment income 25 23 49 44
Net gains (losses) on investments and derivatives 1 (1) (9) (6)
Total revenues 868 772 1,718 1,520
Operating segments | Protection Services | Protection plans        
Segment Reporting Information        
Insurance premiums 531 453 1,041 892
Operating segments | Protection Services | Roadside assistance        
Segment Reporting Information        
Insurance premiums 39 34 75 81
Operating segments | Protection Services | Protection and insurance products        
Segment Reporting Information        
Insurance premiums 125 126 250 252
Operating segments | Allstate Health and Benefits        
Segment Reporting Information        
Other revenue 109 121 240 255
Net investment income 5 25 30 48
Net gains (losses) on investments and derivatives (1) 0 (2) 2
Total revenues 348 620 990 1,257
Operating segments | Allstate Health and Benefits | Employer voluntary benefits        
Segment Reporting Information        
Insurance premiums 0 246 243 494
Operating segments | Allstate Health and Benefits | Group health        
Segment Reporting Information        
Insurance premiums 123 120 247 238
Operating segments | Allstate Health and Benefits | Individual health        
Segment Reporting Information        
Insurance premiums 112 108 232 220
Operating segments | Corporate and Other        
Segment Reporting Information        
Other revenue 23 19 38 39
Net investment income 37 21 59 39
Net gains (losses) on investments and derivatives 46 1 37 2
Total revenues 106 41 134 80
Intersegment eliminations        
Segment Reporting Information        
Total revenues $ (36) $ (39) $ (73) $ (74)