Condensed Consolidated Statements of Operations (unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Accident, health and other policy benefits, remeasurement (gain) loss	$ 1	$ 0	$ 1	$ 0

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