Name:	ci_RealizedInvestmentGainLoss
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The net realized gains or (losses) on investments during the period and still held at the reporting date, including gains (losses) on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

No definition available.

Name:	ci_RealizedInvestmentGainLossInstrumentsStillHeldAtReportingDate
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount after taxes of the net realized gains or (losses) on investments during the period.

No definition available.

Name:	ci_RealizedInvestmentGainsLossesNetOfTaxes
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of tax expense (benefit) on net realized gains or losses on investments during the period.

No definition available.

Name:	ci_RealizedInvestmentGainsLossesTaxes
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_GainLossOnInvestmentsByCategoryAxis=us-gaap_FixedMaturitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_GainLossOnInvestmentsByCategoryAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_GainLossOnInvestmentsByCategoryAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: