v2.4.1.9
Acquisitions and Noncontrolling Interest Non Controlling Interest (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Oct. 31, 2012
Noncontrolling Interest [Line Items]                        
Payments to Acquire Additional Interest in Subsidiaries                 $ 0us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries $ 0us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries $ 14us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries  
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net [Abstract]                        
Income (Loss) from Continuing Operations Attributable to Parent 106us-gaap_IncomeLossFromContinuingOperations 81us-gaap_IncomeLossFromContinuingOperations 47us-gaap_IncomeLossFromContinuingOperations 34us-gaap_IncomeLossFromContinuingOperations 48us-gaap_IncomeLossFromContinuingOperations 50us-gaap_IncomeLossFromContinuingOperations 41us-gaap_IncomeLossFromContinuingOperations 23us-gaap_IncomeLossFromContinuingOperations 268us-gaap_IncomeLossFromContinuingOperations 161us-gaap_IncomeLossFromContinuingOperations 89us-gaap_IncomeLossFromContinuingOperations  
Decrease in equity for purchase of, distribution to and redemption of noncontrolling interest                 0cnc_Decreaseinequityforpurchaseofdistributiontoandredemptionofnoncontrollinginterest 0cnc_Decreaseinequityforpurchaseofdistributiontoandredemptionofnoncontrollinginterest (12)cnc_Decreaseinequityforpurchaseofdistributiontoandredemptionofnoncontrollinginterest  
Increase in equity for distributions from and consolidation of noncontrolling interest                   7us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance 1us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance  
Reclassification to redeemable noncontrolling interest                 (9)cnc_Reclassificationtoredeemablenoncontrollinginterest 0cnc_Reclassificationtoredeemablenoncontrollinginterest 0cnc_Reclassificationtoredeemablenoncontrollinginterest  
Net transfers from (to) noncontrolling interest                 (9)us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesNet 7us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesNet (11)us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangesNet  
Changes from net earnings attributable to Centene Corporation and net transfers from (to) the noncontrolling interest                 259us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet 168us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet 78us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestChangeDueToNetIncomeAttributableToParentAndEffectsOfChangesNet  
Louisiana Healthcare Connections [Member]                        
Noncontrolling Interest [Line Items]                        
Ownership percentage by parent                       51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_LouisianaHealthcareConnectionsMember
Payments to Acquire Additional Interest in Subsidiaries 10us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries
/ dei_LegalEntityAxis
= cnc_LouisianaHealthcareConnectionsMember
                     
Centurion [Member]                        
Noncontrolling Interest [Line Items]                        
Ownership percentage by parent 51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_CenturionMember
      51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_CenturionMember
      51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_CenturionMember
51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_CenturionMember
51.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_CenturionMember
 
Home State Health Plan [Member]                        
Noncontrolling Interest [Line Items]                        
Ownership percentage by parent 95.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_HomeStateHealthPlanMember
      95.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_HomeStateHealthPlanMember
      95.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_HomeStateHealthPlanMember
95.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_HomeStateHealthPlanMember
95.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_HomeStateHealthPlanMember
 
U.S. Medical Management [Member]                        
Noncontrolling Interest [Line Items]                        
Ownership percentage by parent 68.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_U.S.MedicalManagementMember
      0.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_U.S.MedicalManagementMember
      68.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_U.S.MedicalManagementMember
0.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_U.S.MedicalManagementMember
0.00%us-gaap_MinorityInterestOwnershipPercentageByParent
/ dei_LegalEntityAxis
= cnc_U.S.MedicalManagementMember
 
Noncontrolling Interest [Member]                        
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Net [Abstract]                        
Increase in equity for distributions from and consolidation of noncontrolling interest                 $ 0us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
$ 7us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember
$ 1us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance
/ us-gaap_StatementEquityComponentsAxis
= us-gaap_NoncontrollingInterestMember