v2.4.1.9

Condensed Financial Information Of Registrant Basis of Presentation and Significant Accounting Policies (Details) (Parent Company [Member], USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Parent Company [Member] |  |  |
Cash Flows Received By Parent From Unrestricted Subsidiaries | $ 341 cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | $ 313 cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries / dei_LegalEntityAxis = us-gaap_ParentCompanyMember | $ 318 cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries / dei_LegalEntityAxis = us-gaap_ParentCompanyMember

X
- Definition Cash flows received by the parent from unrestricted subsidiaries. + References No definition available. + Details
Name: | cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration