Condensed Consolidated Statements of Operations (unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Accident, health and other policy benefits, remeasurement (gain) loss	$ 0	$ (4)	$ 0	$ (4)

Accident, Health and Other Policy Benefits, Remeasurement (Gain) Loss

No definition available.

Name:	all_AccidentHealthAndOtherPolicyBenefitsRemeasurementGainLoss
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration