XML 103 R85.htm IDEA: XBRL DOCUMENT
v3.21.1

Reserve for Property and Casualty Insurance Claims and Claims Expense - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2021 | Mar. 31, 2020
Increase (decrease) in claims and claims expense |  |
Prior years | $ 241 | $ (8)
Catastrophe |  |
Increase (decrease) in claims and claims expense |  |
Incurred expense (adjustment) | (590) | (211)
Prior years | 243 | $ 20
Southern California Edison | Fire |  |
Increase (decrease) in claims and claims expense |  |
Prior years | $ (110) |

X
- 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_CausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred and costs incurred in the claim settlement process. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
Name: | us-gaap_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
Name: | us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersPriorYearClaimsAndClaimsAdjustmentExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis=us-gaap_CatastropheMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=all_SouthernCaliforniaEdisonMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis=us-gaap_FireMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |