v2.4.1.9

Condensed Financial Information Of Registrant Condensed Balance Sheets (Parenthetical) (Details) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Common stock, par value	$ 0.001us-gaap_CommonStockParOrStatedValuePerShare	$ 0.001us-gaap_CommonStockParOrStatedValuePerShare
Common stock, shares authorized	200,000,000us-gaap_CommonStockSharesAuthorized	200,000,000us-gaap_CommonStockSharesAuthorized
Common Stock, Shares, Issued	124,274,864us-gaap_CommonStockSharesIssued	117,346,430us-gaap_CommonStockSharesIssued
Common Stock, Shares, Outstanding	118,433,416us-gaap_CommonStockSharesOutstanding	110,638,478us-gaap_CommonStockSharesOutstanding
Treasury Stock, Shares	5,841,448us-gaap_TreasuryStockShares	6,707,952us-gaap_TreasuryStockShares
Parent Company [Member]
Short-term investments, Amortized cost	$ 8cnc_ShortTermInvestmentsAmortizedCost / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	$ 6cnc_ShortTermInvestmentsAmortizedCost / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Long-term investments, Amortized cost	$ 10cnc_LongTermInvestmentsAmortizedCost / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	$ 8cnc_LongTermInvestmentsAmortizedCost / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Common stock, par value	$ 0.001us-gaap_CommonStockParOrStatedValuePerShare / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	$ 0.001us-gaap_CommonStockParOrStatedValuePerShare / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Common stock, shares authorized	200,000,000us-gaap_CommonStockSharesAuthorized / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	200,000,000us-gaap_CommonStockSharesAuthorized / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Common Stock, Shares, Issued	124,274,864us-gaap_CommonStockSharesIssued / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	117,346,430us-gaap_CommonStockSharesIssued / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Common Stock, Shares, Outstanding	118,433,416us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	110,638,478us-gaap_CommonStockSharesOutstanding / dei_LegalEntityAxis = us-gaap_ParentCompanyMember
Treasury Stock, Shares	5,841,448us-gaap_TreasuryStockShares / dei_LegalEntityAxis = us-gaap_ParentCompanyMember	6,707,952us-gaap_TreasuryStockShares / dei_LegalEntityAxis = us-gaap_ParentCompanyMember

X

- Definition

The total amount of investments that are intended to be held for an extended period of time, at amortized cost (longer than one operating cycle).

+ References

No definition available.

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- Definition

Short-term investments, at amortized cost.

+ References

No definition available.

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X

- Definition

Face amount or stated value per share of common stock.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

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X

- Definition

The maximum number of common shares permitted to be issued by an entity's charter and bylaws.

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X

- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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- Definition

Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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