XML 117 R104.htm IDEA: XBRL DOCUMENT
v3.22.4

Claim and Claim Adjustment Expense Reserves and Future Policy Benefit Reserves (Life & Group Policyholder Reserves) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022
Liability for Claims and Claims Adjustment Expense [Abstract] |  |  |
Liability for unpaid claims and claims adjustment expense, long term care policies, period increase (decrease) | $ (25) | $ (40) |
Liability for unpaid claims and claims adjustment expense structured settlement obligations period increase (decrease) | (5) | 2 |
Liability for future policy benefits, gross premium valuation, pretax margin | $ 125 | $ 72 | $ 125

X
- Definition Liability for Future Policy Benefits, Gross Premium Valuation, Pretax Margin + References No definition available. + Details
Name: | cna_LiabilityForFuturePolicyBenefitsGrossPremiumValuationPretaxMargin
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Liability for Unpaid Claims and Claims Adjustment Expense, Long Term Care Policies, Period Increase (Decrease) + References No definition available. + Details
Name: | cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseLongTermCarePoliciesPeriodIncreaseDecrease
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Liability For Unpaid Claims And Claims Adjustment Expense Structured Settlement Obligations Period Increase (Decrease) + References No definition available. + Details
Name: | cna_LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseStructuredSettlementObligationsPeriodIncreaseDecrease
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpenseAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration