XML 59 R14.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Legal Proceedings and Contingent Liabilities | 3 Months Ended
--- | ---
Mar. 31, 2013
Legal Proceedings and Contingent Liabilities [Abstract] |
Legal Proceedings and Contingent Liabilities | Note G. Legal Proceedings and Contingent Liabilities The Company is a party to routine litigation incidental to its business, which, based on the facts and circumstances currently known, is not material to the Condensed Consolidated Financial Statements.

X
- Details
Name: | cna_LegalProceedingsAndContingentLiabilitiesAbstract
Namespace Prefix: | cna_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for legal proceedings, legal contingencies, litigation, regulatory and environmental matters and other contingencies. + References No definition available. + Details
Name: | us-gaap_LegalMattersAndContingenciesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration