Name:	all_AssessmentEstimatedMaximumAmount
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the maximum possible assessment amount by a state insurance facility in which the entity participates.

No definition available.

Name:	all_MaximumPossibleAssessmentAmount
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the entity's share in a state insurance facility.

No definition available.

Name:	all_PercentageOfEntityInterest
Namespace Prefix:	all_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

Policy Holder Surcharge

No definition available.

Name:	all_PolicyHolderSurcharge
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Proceeds of Revenue Bonds

No definition available.

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

Represents the projected aggregate claim paying capacity of a state insurance facility in which the entity participates.

No definition available.

Name:	all_ProjectedAggregateClaimPayingCapacity
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents the capital balance of a state insurance facility in which the entity participates.

No definition available.

Name:	all_StateFacilityCapitalBalance
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The capital balance of a state insurance facility, below which an assessment is triggered.

No definition available.

Name:	all_StateFacilityCapitalBalanceThreshold
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Represents funding obtainable by a state insurance facility from an existing reinsurance layer in the event that losses cause a deficit.

No definition available.

Name:	all_StateFacilityExistingReinsuranceLayer
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The capital balance level for a state insurance facility that may be restored through assessments.

No definition available.

Name:	all_StateFacilityMaximumRestoredCapitalBalance
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 720
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483359/720-20-50-1

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 27
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482395/460-10-55-27

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-9

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-4

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 460
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482425/460-10-50-3

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483076/450-20-50-1