XML 66 R56.htm IDEA: XBRL DOCUMENT
v3.23.1

Claim and Claim Adjustment Expense Reserves (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2023 | Mar. 31, 2022 | Dec. 31, 2022 | Dec. 31, 2010
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Unusual or Infrequent Item, or Both, Net of Insurance Proceeds | $ 52 | $ 19 |  |
Retroactive reinsurance benefit recognized | 8 | $ 12 |  |
Cumulative amounts ceded under AEP Loss Portfolio Transfer | 3,500 |  | $ 3,500 |
Asbestos and Environmental Reserves |  |  |  |
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |  |
Net A&EP claim and allocated claim adjustment expense reserves ceded to NICO |  |  |  | $ 1,600
Aggregate limit under A&EP Loss Portfolio Transfer |  |  |  | 4,000
A&EP claim and allocated claim adjustment expense reserves ceded under existing third party reinsurance contracts transferred to NICO under A&EP Loss Portfolio Transfer |  |  |  | 1,200
Reinsurance premium paid to NICO under A&EP Loss Portfolio Transfer |  |  |  | 2,000
Net reinsurance receivables transferred to NICO under A&EP Loss Portfolio Transfer |  |  |  | 215
Total consideration paid to NICO under AEP Loss Portfolio Transfer |  |  |  | $ 2,200
Deferred reinsurance benefit yet to be recognized | 417 |  | $ 425 |
Fair value of collateral trust account established by NICO under A&EP Loss Portfolio Transfer | $ 2,500 |  |  |

X
- Definition Aggregate limit under A&EP Loss Portfolio Transfer + References No definition available. + Details
Name: | cna_AggregateLimitUnderAEPLossPortfolioTransfer
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Claim and allocated claim adjustment expense reserves under existing third party reinsurance contracts. + References No definition available. + Details
Name: | cna_ClaimAndAllocatedClaimAdjustmentExpenseReservesUnderExistingThirdPartyReinsuranceContracts
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Cumulative Amounts Ceded Under AEP Loss Portfolio Transfer + References No definition available. + Details
Name: | cna_CumulativeAmountsCededUnderAEPLossPortfolioTransfer
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Deferred Reinsurance Benefit Yet To Be Recognized + References No definition available. + Details
Name: | cna_DeferredReinsuranceBenefitYetToBeRecognized
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of collateral trust account established by NICO under A&EP Loss Portfolio Transfer + References No definition available. + Details
Name: | cna_FairValueOfCollateralTrustAccountEstablishedByNICOUnderAEPLossPortfolioTransfer
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Net reinsurance receivables transferred to NICO under A&EP Loss Portfolio Transfer + References No definition available. + Details
Name: | cna_NetReinsuranceReceivablesTransferredToNICOUnderAEPLossPortfolioTransfer
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Reinsurance premium paid to NICO under A&EP Loss Portfolio Transfer + References No definition available. + Details
Name: | cna_ReinsurancePremiumPaidToNICOUnderAEPLossPortfolioTransfer
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Retroactive Reinsurance Benefit Recognized + References No definition available. + Details
Name: | cna_RetroactiveReinsuranceBenefitRecognized
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Total Consideration Paid To NICO Under AEP Loss Portfolio Transfer + References No definition available. + Details
Name: | cna_TotalConsiderationPaidToNICOUnderAEPLossPortfolioTransfer
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process attributable to asbestos and environmental claims, net of estimated reinsurance recoveries. + 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 (a) -URI https://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (cc) -URI https://asc.fasb.org/extlink&oid=116884095&loc=d3e14764-158437 + Details
Name: | us-gaap_LiabilityForAsbestosAndEnvironmentalClaimsNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Amount, after deduction of insurance proceeds, of loss recognized in the income statement for an event or transaction that is unusual in nature or infrequent in occurrence, or both. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 930 -SubTopic 715 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=109241964&loc=d3e23713-110274 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 20 -Section 50 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=114868883&loc=SL114871943-224233 + Details
Name: | us-gaap_UnusualOrInfrequentItemNetOfInsuranceProceeds
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_ProductOrServiceAxis=cna_AsbestosandEnvironmentalReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |