v2.4.1.9
Condensed Financial Information Of Registrant (Condensed Balance Sheets) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Cash and cash equivalents $ 1,610us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations $ 1,038us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations $ 844us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations $ 574us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations
Short term investments 177us-gaap_ShortTermInvestments 102us-gaap_ShortTermInvestments    
Other current assets 324us-gaap_OtherAssetsCurrent 217us-gaap_OtherAssetsCurrent    
Total current assets 3,034us-gaap_AssetsCurrent 1,800us-gaap_AssetsCurrent    
Long term investments 1,280us-gaap_LongTermInvestments 792us-gaap_LongTermInvestments    
Other long term assets 80us-gaap_OtherAssetsNoncurrent 60us-gaap_OtherAssetsNoncurrent    
Total assets 5,838us-gaap_Assets 3,529us-gaap_Assets    
Current liabilities 2,900us-gaap_LiabilitiesCurrent 1,559us-gaap_LiabilitiesCurrent    
Long term debt 888us-gaap_LongTermDebtNoncurrent 666us-gaap_LongTermDebtNoncurrent    
Other long term liabilities 158us-gaap_OtherLiabilitiesNoncurrent 60us-gaap_OtherLiabilitiesNoncurrent    
Total liabilities 3,947us-gaap_Liabilities 2,286us-gaap_Liabilities    
Redeemable noncontrolling interest 148us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount 0us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount    
Common stock, $.001 par value; authorized 200,000,000 shares; 124,274,864 issued and 118,433,416 outstanding at December 31, 2014, and 117,346,430 issued and 110,638,478 outstanding at December 31, 2013 0us-gaap_CommonStockValue 0us-gaap_CommonStockValue    
Additional paid-in capital 840us-gaap_AdditionalPaidInCapitalCommonStock 594us-gaap_AdditionalPaidInCapitalCommonStock    
Retained earnings 1,003us-gaap_RetainedEarningsAccumulatedDeficit 732us-gaap_RetainedEarningsAccumulatedDeficit    
Treasury stock, at cost (5,841,448 and 6,707,952 shares, respectively) (98)us-gaap_TreasuryStockValue (89)us-gaap_TreasuryStockValue    
Total Centene stockholders’ equity 1,744us-gaap_StockholdersEquity 1,234us-gaap_StockholdersEquity    
Noncontrolling interest (1)us-gaap_MinorityInterest 9us-gaap_MinorityInterest    
Total stockholders’ equity 1,743us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest 1,243us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest 954us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest 937us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
Total liabilities and stockholders’ equity 5,838us-gaap_LiabilitiesAndStockholdersEquity 3,529us-gaap_LiabilitiesAndStockholdersEquity    
Parent Company [Member]        
Income Taxes Receivable 359us-gaap_IncomeTaxReceivable
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
113us-gaap_IncomeTaxReceivable
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Cash and cash equivalents 3us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
3us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
22us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
29us-gaap_CashAndCashEquivalentsAtCarryingValueIncludingDiscontinuedOperations
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
Short term investments 8us-gaap_ShortTermInvestments
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
6us-gaap_ShortTermInvestments
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Other current assets 378us-gaap_OtherAssetsCurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
125us-gaap_OtherAssetsCurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Total current assets 389us-gaap_AssetsCurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
134us-gaap_AssetsCurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Long term investments 10us-gaap_LongTermInvestments
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
8us-gaap_LongTermInvestments
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Investment in subsidiaries 2,296us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
1,667us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Other long term assets 38us-gaap_OtherAssetsNoncurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
32us-gaap_OtherAssetsNoncurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Total assets 2,733us-gaap_Assets
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
1,841us-gaap_Assets
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Current liabilities 24us-gaap_LiabilitiesCurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
5us-gaap_LiabilitiesCurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Long term debt 815us-gaap_LongTermDebtNoncurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
591us-gaap_LongTermDebtNoncurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Other long term liabilities 3us-gaap_OtherLiabilitiesNoncurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
2us-gaap_OtherLiabilitiesNoncurrent
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Total liabilities 842us-gaap_Liabilities
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
598us-gaap_Liabilities
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Redeemable noncontrolling interest 148us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
0us-gaap_RedeemableNoncontrollingInterestEquityCarryingAmount
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Common stock, $.001 par value; authorized 200,000,000 shares; 124,274,864 issued and 118,433,416 outstanding at December 31, 2014, and 117,346,430 issued and 110,638,478 outstanding at December 31, 2013 0us-gaap_CommonStockValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
0us-gaap_CommonStockValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Additional paid-in capital 840us-gaap_AdditionalPaidInCapitalCommonStock
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
594us-gaap_AdditionalPaidInCapitalCommonStock
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Unrealized gain on investments, net of tax (1)us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
(3)us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Retained earnings 1,003us-gaap_RetainedEarningsAccumulatedDeficit
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
732us-gaap_RetainedEarningsAccumulatedDeficit
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Treasury stock, at cost (5,841,448 and 6,707,952 shares, respectively) (98)us-gaap_TreasuryStockValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
(89)us-gaap_TreasuryStockValue
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Total Centene stockholders’ equity 1,744us-gaap_StockholdersEquity
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
1,234us-gaap_StockholdersEquity
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Noncontrolling interest (1)us-gaap_MinorityInterest
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
9us-gaap_MinorityInterest
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Total stockholders’ equity 1,743us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
1,243us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
   
Total liabilities and stockholders’ equity $ 2,733us-gaap_LiabilitiesAndStockholdersEquity
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
$ 1,841us-gaap_LiabilitiesAndStockholdersEquity
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember