Name:	all_CatastropheInsuranceAnnualCoverageLimitRetentionPercentage
Namespace Prefix:	all_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

Represents the number of reinstatements each year for each contract.

No definition available.

Name:	all_CatastropheInsuranceNumberOfReinstatementsPerYear
Namespace Prefix:	all_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

The limit of aggregated losses per contract year beyond which coverage provided by an aggregate excess agreement applies.

No definition available.

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

Represents the retention amount of catastrophe reinsurance agreement contracts.

No definition available.

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

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479838/944-20-50-3

Name:	us-gaap_ReinsuranceRetentionPolicyLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	all_ReinsuranceAgreementAxis=all_TraditionalMarketPlacementOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_CededCreditRiskAxis=all_NationalGeneralLenderServicesStandaloneProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_CededCreditRiskAxis=all_NationalGeneralFloridaHurricaneCatastropheProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: