Guarantees and Contingent Liabilities (Details)	9 Months Ended
	Sep. 30, 2023 USD ($) claim	Nov. 11, 2016 officer
Holland Hewitt v. Allstate Life Insurance Company
Guarantor Obligations [Line Items]
Number of putative class actions | claim	2
The Allstate Corp. Securities Litigation
Guarantor Obligations [Line Items]
Number of officers | officer		2
Minimum
Guarantor Obligations [Line Items]
Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued	$ 0
Maximum
Guarantor Obligations [Line Items]
Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued	$ 67,000,000