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 $ 341cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		 $ 313cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember		 $ 318cnc_CashFlowsReceivedByParentFromUnrestrictedSubsidiaries
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember