XML 33 R30.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Investments (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended |
--- | --- | ---
Mar. 31, 2013 | Mar. 31, 2012 | Dec. 31, 2012
Net unrealized gains (losses) related to changes in fair value of trading securities still held included in net investment income | $ 1 |  |
Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments | 1,438 |  | 1,511
Pretax net unrealized gains (losses) on other available-for-sale securities reclassified out of AOCI and recognized in earnings | 19 | 32 |
Future capital call commitments for limited partnership investments | 247 |  |
Mortgage loan commitments | 29 |  |
Commitments to purchase or fund privately placed debt securities | 167 |  |
Commitments to sell various privately placed debt securities | $ 210 |  |

X
- Definition Commitments To Purchase Various Privately Placed Debt Securities + 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 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 The amount of pretax net unrealized gains (losses) on other available-for-sale securities reclassified out of AOCI and recognized in earnings + References No definition available. + Details
Name: | cna_PretaxNetUnrealizedGainsLossesOnOtherAvailableForSaleSecuritiesReclassifiedOutOfAociAndRecognizedInEarnings
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Reduction of net unrealized gains on investments included in AOCI due to shadow adjustments + References No definition available. + Details
Name: | cna_ReductionOfNetUnrealizedGainsOnInvestmentsIncludedInAociDueToShadowAdjustments
Namespace Prefix: | cna_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of trading securities held at each balance sheet date, that was included in earnings for the period. Trading securities are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) and the change in net unrealized holding gain (loss) is included in earnings for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 21 -Subparagraph e -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 13 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=6872113&loc=d3e27357-111563 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 12 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c)) -URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=16383099&loc=d3e24584-111560 + Details
Name: | us-gaap_TradingSecuritiesUnrealizedHoldingGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration