XML 65 R52.htm IDEA: XBRL DOCUMENT
v3.22.4

Investments (Summary of fixed maturity and equity securities) (Details) - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | --- | ---
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | $ 41,032 | $ 39,945 |
Gross Unrealized Gains | 652 | 4,558 |
Gross Unrealized Losses | 4,056 | 112 |
Allowance for Credit Losses | 1 | 18 | $ 40
Estimated Fair Value | 37,627 | 44,373 |
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract] |  |  |
Total fixed maturity securities trading | 0 | 7 |
Total fixed maturity securities trading | 0 | 7 |
Debt securities, amortized cost | 41,032 | 39,952 |
Total fixed maturity securities | 37,627 | 44,380 |
Corporate and other bonds |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 23,137 | 21,444 |
Gross Unrealized Gains | 301 | 2,755 |
Gross Unrealized Losses | 2,009 | 56 |
Allowance for Credit Losses | 0 | 11 | 23
Estimated Fair Value | 21,429 | 24,132 |
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract] |  |  |
Total fixed maturity securities | 22,117 | 24,852 |
States, municipalities and political subdivisions |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 8,918 | 10,358 |
Gross Unrealized Gains | 338 | 1,599 |
Gross Unrealized Losses | 939 | 14 |
Allowance for Credit Losses | 0 | 0 |
Estimated Fair Value | 8,317 | 11,943 |
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract] |  |  |
Total fixed maturity securities | 8,317 | 11,943 |
Residential mortgage-backed |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 3,073 | 2,893 |
Gross Unrealized Gains | 5 | 71 |
Gross Unrealized Losses | 447 | 8 |
Allowance for Credit Losses | 0 | 0 |
Estimated Fair Value | 2,631 | 2,956 |
Commercial mortgage-backed |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 1,886 | 1,987 |
Gross Unrealized Gains | 4 | 63 |
Gross Unrealized Losses | 255 | 19 |
Allowance for Credit Losses | 0 | 0 |
Estimated Fair Value | 1,635 | 2,031 |
Other asset-backed |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 3,287 | 2,561 |
Gross Unrealized Gains | 2 | 54 |
Gross Unrealized Losses | 361 | 10 |
Allowance for Credit Losses | 1 | 7 |
Estimated Fair Value | 2,927 | 2,598 |
Asset-backed |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 8,246 | 7,441 |
Gross Unrealized Gains | 11 | 188 |
Gross Unrealized Losses | 1,063 | 37 |
Allowance for Credit Losses | 1 | 7 | $ 17
Estimated Fair Value | 7,193 | 7,585 |
Debt Securities, Trading, Unrealized Gain (Loss) [Abstract] |  |  |
Total fixed maturity securities | 7,193 | 7,585 |
U.S. Treasury and obligations of government-sponsored enterprises |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 111 | 132 |
Gross Unrealized Gains | 1 | 1 |
Gross Unrealized Losses | 2 | 3 |
Allowance for Credit Losses | 0 | 0 |
Estimated Fair Value | 110 | 130 |
Foreign government |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 617 | 570 |
Gross Unrealized Gains | 1 | 15 |
Gross Unrealized Losses | 43 | 2 |
Allowance for Credit Losses | 0 | 0 |
Estimated Fair Value | 575 | 583 |
Redeemable preferred stock |  |  |
Fixed maturity securities available-for-sale: |  |  |
Cost or Amortized Cost | 3 | 0 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Allowance for Credit Losses | 0 | 0 |
Estimated Fair Value | $ 3 | $ 0 |

X
- Definition Debt Securities, Amortized Cost + References No definition available. + Details
Name: | cna_DebtSecuritiesAmortizedCost
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References No definition available. + Details
Name: | us-gaap_DebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 30 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=124260329&loc=d3e26610-111562 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (f) -URI https://asc.fasb.org/extlink&oid=124098289&loc=d3e6676-107765 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_TradingSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized cost of investments in debt securities classified as trading. + References No definition available. + Details
Name: | us-gaap_TradingSecuritiesDebtAmortizedCost
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_ResidentialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_RedeemablePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |