No definition available.

Name:	all_DerivativeFinancialInstrumentsAndOffBalanceSheetFinancialInstrumentsDisclosureAbstract
Namespace Prefix:	all_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of the credit risk derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-Subparagraph (a)(1)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5708775-113959

+ Details

Name:	us-gaap_CreditDerivativeTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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

- Definition

Fair value of credit risk derivative asset after deduction of credit risk derivative liability.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4K
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5708775-113959

+ Details

Name:	us-gaap_CreditRiskDerivativesAtFairValueNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_CreditDerivativesByContractTypeAxis=us-gaap_CreditDefaultSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=all_SingleNameMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ExternalCreditRatingByGroupingAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_UnderlyingAssetClassAxis=all_IndexMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CreditRatingStandardPoorsAxis=srt_StandardPoorsAAARatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CreditRatingStandardPoorsAxis=srt_StandardPoorsAARatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CreditRatingStandardPoorsAxis=srt_StandardPoorsARatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CreditRatingStandardPoorsAxis=srt_StandardPoorsBBBRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CreditRatingStandardPoorsAxis=all_StandardPoorsBBAndLowerRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Derivative Financial Instruments and Off-balance Sheet Financial Instruments - CDS notional amount by credit rating and fair value of protection sold (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Derivative Financial Instruments and Off-balance sheet Financial Instruments
Term of credit default swaps	5 years
Credit Derivatives
Derivative, notional amount	$ 1,436	$ 2,075
Credit default contracts
Credit Derivatives
Derivative, notional amount		255
Fair value		6
Credit default contracts \| Single name \| Corporate
Credit Derivatives
Derivative, notional amount		5
Fair value		0
Credit default contracts \| Index \| Corporate
Credit Derivatives
Derivative, notional amount		250
Fair value		6
AAA \| Credit default contracts
Credit Derivatives
Derivative, notional amount		2
AAA \| Credit default contracts \| Single name \| Corporate
Credit Derivatives
Derivative, notional amount		0
AAA \| Credit default contracts \| Index \| Corporate
Credit Derivatives
Derivative, notional amount		2
AA \| Credit default contracts
Credit Derivatives
Derivative, notional amount		4
AA \| Credit default contracts \| Single name \| Corporate
Credit Derivatives
Derivative, notional amount		0
AA \| Credit default contracts \| Index \| Corporate
Credit Derivatives
Derivative, notional amount		4
A \| Credit default contracts
Credit Derivatives
Derivative, notional amount		46
A \| Credit default contracts \| Single name \| Corporate
Credit Derivatives
Derivative, notional amount		0
A \| Credit default contracts \| Index \| Corporate
Credit Derivatives
Derivative, notional amount		46
NAIC 2 / BBB \| Credit default contracts
Credit Derivatives
Derivative, notional amount		190
NAIC 2 / BBB \| Credit default contracts \| Single name \| Corporate
Credit Derivatives
Derivative, notional amount		0
NAIC 2 / BBB \| Credit default contracts \| Index \| Corporate
Credit Derivatives
Derivative, notional amount		190
BB and lower \| Credit default contracts
Credit Derivatives
Derivative, notional amount		13
BB and lower \| Credit default contracts \| Single name \| Corporate
Credit Derivatives
Derivative, notional amount		5
BB and lower \| Credit default contracts \| Index \| Corporate
Credit Derivatives
Derivative, notional amount		$ 8