v2.4.1.9

Debt (Narrative) (Details) In Millions, unless otherwise specified | 3 Months Ended |  |  |  |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2014 USD ($) | Apr. 30, 2014 USD ($) | Dec. 31, 2013 USD ($) | May 31, 2013 USD ($) | May 31, 2011 USD ($) | Apr. 30, 2014 Four Point Seven Five Percent Senior Notes [Member] USD ($) | May 31, 2011 Five Point Seven Five Percent Senior Notes [Member] USD ($) | Dec. 31, 2014 Non-recourse Mortgage Note Due January 1, 2021 [Member] USD ($) | Dec. 31, 2014 Ribera Salud [Member] USD ($) | Dec. 31, 2014 Ribera Salud [Member] EUR (€) | Dec. 31, 2014 Non Revolver Letter of Credit [Member] USD ($) | Dec. 31, 2014 Interest Rate Swap [Member] USD ($)
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Covenant Terms | The agreement contains non-financial and financial covenants, including requirements of minimum fixed charge coverage ratios, maximum debt-to-EBITDA ratios and minimum tangible net worth. The Company is required to not exceed a maximum debt-to-EBITDA ratio of 3.0 to 1.0. |  |  |  |  |  |  |  |  |  |  |
Mortgage notes payable | $ 70 us-gaap_OtherNotesPayable |  | $ 73 us-gaap_OtherNotesPayable |  |  |  |  |  |  |  |  |
Line of Credit Facility, Current Borrowing Capacity | 500 us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity |  |  |  |  |  |  |  |  |  |  |
Senior notes, at par | 429 cnc_SeniorNotesAtPar |  | 431 cnc_SeniorNotesAtPar |  |  | 300 cnc_SeniorNotesAtPar / us-gaap_LongtermDebtTypeAxis = cnc_FourPointSevenFivePercentSeniorNotesMember | 425 cnc_SeniorNotesAtPar / us-gaap_LongtermDebtTypeAxis = cnc_FivePointSevenFivePercentSeniorNotesMember |  |  |  |  |
Derivative, Notional Amount |  | 300 invest_DerivativeNotionalAmount |  |  | 250 invest_DerivativeNotionalAmount |  |  |  |  |  |  | 550 invest_DerivativeNotionalAmount / us-gaap_VariableRateAxis = us-gaap_InterestRateSwapMember
Interest rate on notes, percentage |  |  |  |  |  | 4.75%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_LongtermDebtTypeAxis = cnc_FourPointSevenFivePercentSeniorNotesMember | 5.75%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_LongtermDebtTypeAxis = cnc_FivePointSevenFivePercentSeniorNotesMember |  |  |  |  |
Debt Instrument, Maturity Date |  |  |  |  |  | May 15, 2022 | Jun. 01, 2017 | Jan. 01, 2021 |  |  |  |
Senior notes, effective yield | 1.73%us-gaap_DebtInstrumentInterestRateEffectivePercentage |  |  |  |  |  |  |  |  |  |  |
Debt Instrument, Unamortized Premium | 300 us-gaap_DebtInstrumentUnamortizedPremium |  | 0 us-gaap_DebtInstrumentUnamortizedPremium |  |  |  |  |  |  |  |  |
Fair value of swap agreements | 11 us-gaap_InterestRateDerivativeAssetsAtFairValue |  | 10 us-gaap_InterestRateDerivativeAssetsAtFairValue |  |  |  |  |  |  |  |  |
Variable rate of swap, percentage |  |  |  |  |  |  |  |  |  |  |  | 2.83%us-gaap_DerivativeVariableInterestRate / us-gaap_VariableRateAxis = us-gaap_InterestRateSwapMember
weighted average interest rate, interest rate swap agreements |  |  |  |  |  |  |  |  |  |  |  | 3.06%cnc_Weightedaverageinterestrateinterestrateswapagreements / us-gaap_VariableRateAxis = us-gaap_InterestRateSwapMember
Revolving credit facility, maximum borrowing capacity |  |  |  | 500 us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity |  |  |  |  |  |  |  |
Revolving credit facility, due date | Jun. 01, 2018 |  |  |  |  |  |  |  |  |  |  |
Line of Credit, Minimum carrying amount of unrestricted cash | 100 cnc_LineofCreditMinimumcarryingamountofunrestrictedcash |  |  |  |  |  |  |  |  |  |  |
Line of Credit Facility, Amount Outstanding | 75 us-gaap_LineOfCredit |  | 150 us-gaap_LineOfCredit |  |  |  |  |  |  |  |  |
Letters of Credit Outstanding, Amount |  |  |  |  |  |  |  |  | 58 us-gaap_LettersOfCreditOutstandingAmount / dei_LegalEntityAxis = cnc_RiberaSaludMember | 48 us-gaap_LettersOfCreditOutstandingAmount / dei_LegalEntityAxis = cnc_RiberaSaludMember | 30 us-gaap_LettersOfCreditOutstandingAmount / us-gaap_CreditFacilityAxis = cnc_NonRevolverLetterofCreditMember |
Mortgage note non-recourse interest rate |  |  |  |  |  |  |  | 5.14%us-gaap_MortgageLoansOnRealEstateInterestRate / us-gaap_LongtermDebtTypeAxis = cnc_NonRecourseMortgageNoteDueJanuary12021Member |  |  |  |
Net Book Value Of Collateralized Properties |  |  |  |  |  |  |  | 159 cnc_NetBookValueOfCollateralizedProperties / us-gaap_LongtermDebtTypeAxis = cnc_NonRecourseMortgageNoteDueJanuary12021Member |  |  |  |
Weighted average interest rate of outstanding borrowings | 1.91%us-gaap_DebtWeightedAverageInterestRate |  |  |  |  |  |  |  |  |  |  |
Surety Bonds | 142 us-gaap_GuaranteeObligationsMaximumExposure |  |  |  |  |  |  |  |  |  |  |
Fair value of outstanding debt | $ 901 us-gaap_LongTermDebtFairValue |  | $ 673 us-gaap_LongTermDebtFairValue |  |  |  |  |  |  |  |  |

X
- Definition Line of Credit, Minimum carrying amount of unrestricted cash + References No definition available. + Details
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Balance Type: | debit
Period Type: | instant

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- Definition Net book value of collateralized properties + References No definition available. + Details
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Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Senior Notes At Par + References No definition available. + Details
Name: | cnc_SeniorNotesAtPar
Namespace Prefix: | cnc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition weighted average interest rate, interest rate swap agreements + References No definition available. + Details
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Namespace Prefix: | cnc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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X
- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Details
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X
- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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Balance Type: | na
Period Type: | duration

X
- Definition The amount of debt premium that was originally recognized at the issuance of the instrument that has yet to be amortized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Weighted average interest rate of debt outstanding. + References No definition available. + Details
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- Definition Variable interest rate in effect as of the balance sheet date related to the interest rate derivative. + References No definition available. + Details
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X
- Definition Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value as of the balance sheet date of interest rate derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611 + Details
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Balance Type: | debit
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X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Description of the conditions for borrowing under the credit facility including the nature of any restrictions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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Balance Type: | na
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X
- Definition Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Date the credit facility terminates, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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Balance Type: | na
Period Type: | duration

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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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Balance Type: | credit
Period Type: | instant

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
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Balance Type: | credit
Period Type: | instant

X
- Definition The stated interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 10 -Section S99 -Paragraph 6 -Subparagraph (SX 210.5-04.(c) Schedule IV) -URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 29 -Article 12 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule IV -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 + Details
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- Definition Including the current and noncurrent portions, the carrying value of notes payable which were initially due after one year or beyond the normal operating cycle, if longer, and which are not otherwise defined in the taxonomy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20, 22 -Article 5 + Details
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