Statutory Financial Information and Dividend Limitations - Schedule of Statutory Net Income (Loss) and Capital and Surplus of Allstate’s Domestic Insurance Subsidiaries (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Amount per statutory accounting practices
Net income (loss)	$ 8,792	$ 4,219	$ (426)
Capital and surplus	22,946	18,635
Employer voluntary benefits	98
Property and casualty insurance
Amount per statutory accounting practices
Net income (loss)	8,690	4,158	(487)
Capital and surplus	22,845	18,243
Accident and health insurance
Amount per statutory accounting practices
Net income (loss)	102	61	$ 61
Capital and surplus	$ 101	$ 392

Statutory Financial Information and Dividend Limitations - Schedule of Statutory Net Income (Loss) and Capital and Surplus of Allstate’s Domestic Insurance Subsidiaries (Details) - USD ($)
$ in Millions

12 Months Ended

Dec. 31, 2025

Dec. 31, 2024

Dec. 31, 2023

Amount per statutory accounting practices

Net income (loss)

$ 8,792

$ 4,219

$ (426)

Capital and surplus

22,946

18,635