XML 64 R47.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Investments (Narrative) (Details) - USD ($) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Gain (Loss) on Investments [Line Items] |  |  |
Non-income producing fixed maturity securities | $ 2,000,000 | $ 0 |
Investments that exceed ten percent of stockholders' equity | 0 | 0 |
Repayments of senior debt | 350,000,000 |  |
Limited partnership investments | 2,369,000,000 | 2,371,000,000 |
Undistributed earnings of limited partnership investments | $ 539,000,000 | $ 523,000,000 |
Percentage of limited partnerships reported on a current basis | 61.00% |  |
Percentage of limited partnerships reported on a one month lag | 18.00% |  |
Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments | 71.00% | 68.00% |
Limited partnerships invested in private debt and equity | 25.00% | 27.00% |
Percentage of equity related limited partnership hedge fund strategies | 62.00% |  |
Percentage of multistrategy approach limited partnership hedge fund strategies | 19.00% |  |
Percentage of distressed investments limited partnership hedge fund strategies | 17.00% |  |
Percentage of fixed income limited partnership hedge fund strategies | 2.00% |  |
Carrying value of ten largest limited partnerships | $ 1,136,000,000 | $ 1,168,000,000 |
Carrying value of limited partnerships as percentage of aggregate partnership equity | 3.00% | 4.00% |
Income As Percentage Of Change In Partnership Equity For All Limited Partnerships | 3.00% | 4.00% | 3.00%
RIght to reclaim cash | $ 0 | $ 0 |
Obligation to return cash | 0 | 0 |
Derivative, notional amount | 167,000,000 | 174,000,000 |
Derivative liability, fair value, gross liability | 3,000,000 | (3,000,000) |
Future capital call commitments for limited partnership investments | 384,000,000 |  |
Mortgage loan commitments | 46,000,000 |  |
Commitments to purchase or fund privately placed debt securities | 165,000,000 |  |
Commitments to sell various privately placed debt securities | 108,000,000 |  |
Carrying value of securities deposited under requirements of regulatory authorities | 2,600,000,000 | 2,300,000,000 |
Cash and securities deposited as collateral for letters of credit | 471,000,000 | 514,000,000 |
Carrying value of assets deposited to secure reinsurance and third party obligations | 587,000,000 | 261,000,000 |
Non-income producing fixed maturity securities | 2,000,000 | 0 |
Investments that exceed ten percent of stockholders' equity | 0 | 0 |
Repayments of senior debt | 350,000,000 |  |
Limited partnership investments | 2,369,000,000 | 2,371,000,000 |
Undistributed earnings of limited partnership investments | $ 539,000,000 | $ 523,000,000 |
Percentage of limited partnerships reported on a current basis | 61.00% |  |
Percentage of limited partnerships reported on a one month lag | 18.00% |  |
Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments | 71.00% | 68.00% |
Limited partnerships invested in private debt and equity | 25.00% | 27.00% |
Percentage of equity related limited partnership hedge fund strategies | 62.00% |  |
Percentage of multistrategy approach limited partnership hedge fund strategies | 19.00% |  |
Percentage of distressed investments limited partnership hedge fund strategies | 17.00% |  |
Percentage of fixed income limited partnership hedge fund strategies | 2.00% |  |
Carrying value of ten largest limited partnerships | $ 1,136,000,000 | $ 1,168,000,000 |
Carrying value of limited partnerships as percentage of aggregate partnership equity | 3.00% | 4.00% |
Income As Percentage Of Change In Partnership Equity For All Limited Partnerships | 3.00% | 4.00% | 3.00%
RIght to reclaim cash | $ 0 | $ 0 |
Obligation to return cash | 0 | 0 |
Derivative, notional amount | 167,000,000 | 174,000,000 |
Derivative liability, fair value, gross liability | (3,000,000) | 3,000,000 |
Future capital call commitments for limited partnership investments | 384,000,000 |  |
Mortgage loan commitments | 46,000,000 |  |
Commitments to purchase or fund privately placed debt securities | 165,000,000 |  |
Commitments to sell various privately placed debt securities | 108,000,000 |  |
Carrying value of securities deposited under requirements of regulatory authorities | 2,600,000,000 | 2,300,000,000 |
Cash and securities deposited as collateral for letters of credit | 471,000,000 | 514,000,000 |
Carrying value of assets deposited to secure reinsurance and third party obligations | 587,000,000 | $ 261,000,000 |
Senior Notes, Due November 2019 |  |  |
Gain (Loss) on Investments [Line Items] |  |  |
Realized investment gains (losses) | 42,000,000 |  |
Realized investment gains (losses) | $ 42,000,000 |  |

X
- Definition Carrying Value of Assets Deposited to Secure Reinsurance and Third Party Obligations + References No definition available. + Details
Name: | cna_CarryingValueOfAssetsDepositedToSecureReinsuranceAndThirdPartyObligations
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying value Of Limited Partnerships As Percentage of Aggregate Partnership Equity + References No definition available. + Details
Name: | cna_CarryingValueOfLimitedPartnershipsAsPercentageOfAggregatePartnershipEquity
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Carrying Value Of Securities Deposited Under Requirements Of Regulatory Authorities + References No definition available. + Details
Name: | cna_CarryingValueOfSecuritiesDepositedUnderRequirementsOfRegulatoryAuthorities
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying Value Of Ten Largest Limited Partnerships + References No definition available. + Details
Name: | cna_CarryingValueOfTenLargestLimitedPartnerships
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Cash And Securities Deposited As Collateral For Letters Of Credit + References No definition available. + Details
Name: | cna_CashAndSecuritiesDepositedAsCollateralForLettersOfCredit
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Commitments To Purchase Or Fund Additional Amounts + References No definition available. + Details
Name: | cna_CommitmentsToPurchaseOrFundAdditionalAmounts
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Commitments To Sell Various Privately Placed Debt Securities + References No definition available. + Details
Name: | cna_CommitmentsToSellVariousPrivatelyPlacedDebtSecurities
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Future capital call commitments to limited partnerships for which we would receive an ownership interest. + References No definition available. + Details
Name: | cna_FutureCapitalCallCommitments
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Income As Percentage Of Change In Partnership Equity For All Limited Partnerships + References No definition available. + Details
Name: | cna_IncomeAsPercentageOfChangeInPartnershipEquityForAllLimitedPartnerships
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Investments that Exceed Ten Percent of Stockholders' Equity, other than investments in U.S. Treasury and U.S. Government agency securities. + References No definition available. + Details
Name: | cna_InvestmentsthatExceedTenPercentofStockholdersEquity
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in limited partnerships. + References No definition available. + Details
Name: | cna_LimitedPartnershipInvestments
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Limited Partnerships Invested In Private Debt and Equity + References No definition available. + Details
Name: | cna_LimitedPartnershipsInvestedInPrivateDebtAndEquity
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Mortgage loan commitments, representing signed loan applications received and accepted. + References No definition available. + Details
Name: | cna_MortgageLoanCommitments
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Non-Income Producing Fixed Maturity Securities + References No definition available. + Details
Name: | cna_NonIncomeProducingFixedMaturitySecurities
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Percentage of Distressed Investments Limited Partnership Hedge Fund Strategies + References No definition available. + Details
Name: | cna_PercentageOfDistressedInvestmentsLimitedPartnershipHedgeFundStrategies
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Equity Related Limited Partnership Hedge Fund Strategies + References No definition available. + Details
Name: | cna_PercentageOfEquityRelatedLimitedPartnershipHedgeFundStrategies
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Fixed Income Limited Partnership Hedge Fund Strategies + References No definition available. + Details
Name: | cna_PercentageOfFixedIncomeLimitedPartnershipHedgeFundStrategies
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of limited partnerships employing hedge fund strategies focused on fixed income and equity investments + References No definition available. + Details
Name: | cna_PercentageOfLimitedPartnershipsEmployingHedgeFundStrategiesFocusedOnFixedIncomeAndEquityInvestments
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of total carrying value of limited partnerships reported on a current basis + References No definition available. + Details
Name: | cna_PercentageOfLimitedPartnershipsReportedOnCurrentBasis
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of total carrying value of limited partnerships reported on a one month lag. + References No definition available. + Details
Name: | cna_PercentageOfLimitedPartnershipsReportedOnOneMonthLag
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Percentage of Multistrategy Approach Limited Partnership Hedge Fund Strategies + References No definition available. + Details
Name: | cna_PercentageOfMultistrategyApproachLimitedPartnershipHedgeFundStrategies
Namespace Prefix: | cna_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of obligation to return cash collateral under master netting arrangements that have not been offset against derivative assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41678-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226016-175313 + Details
Name: | us-gaap_DerivativeCollateralObligationToReturnCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of right to receive cash collateral under master netting arrangements that have not been offset against derivative liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226016-175313 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41678-113959 + Details
Name: | us-gaap_DerivativeCollateralRightToReclaimCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=82924980&loc=SL51823488-111719 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226000-175313 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.3(a)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 325 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=75031664&loc=d3e22529-158502 + Details
Name: | us-gaap_RealizedInvestmentGainsLosses
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow for a long-term debt where the holder has highest claim on the entity's asset in case of bankruptcy or liquidation during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585 + Details
Name: | us-gaap_RepaymentsOfSeniorDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of consolidated retained earnings that represent undistributed (not yet received) earnings from 50% or less owned persons accounted for by the equity method (equity method investees). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 852 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6462270&loc=d3e57205-112772 + Details
Name: | us-gaap_RetainedEarningsUndistributedEarningsFromEquityMethodInvestees
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_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=cna_SeniorNotesDueNovember2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |