Name:	ci_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLossBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Available For Sale Securities Continuous Unrealized Loss Position Less Than 12 Months Accumulated Loss Before Reclassification To Disposal Group Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLossBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Amortized Cost Before Reclassification To Disposal Group Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsAmortizedCostBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Available For Sale Securities Continuous Unrealized Loss Position Less Than Twelve Months Fair Value Before Reclassification To Disposal Group Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValueBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Amortized Cost Before Reclassification To Disposal Group Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerAmortizedCostBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Available For Sale Securities Continuous Unrealized Loss Position Twelve Months Or Longer Fair Value Before Reclassification To Disposal Group Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValueBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Available For Sale Securities In Unrealized Loss Positions, Qualitative Disclosure, Less Than 12 Months, Number Of Positions, Before Reclassification To Disposal Group, Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureLessThan12MonthsNumberOfPositionsBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Available For Sale Securities In Unrealized Loss Positions, Qualitative Disclosure, Number Of Positions, Before Reclassification To Disposal Group, Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositionsBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Available For Sale Securities In Unrealized Loss Positions, Qualitative Disclosure, Twelve Months Or Longer, Number Of Positions, Before Reclassification To Disposal Group, Assets Held For Sale

No definition available.

Name:	ci_AvailableForSaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureTwelveMonthsOrLongerNumberOfPositionsBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months Or Longer

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAbstract
Namespace Prefix:	ci_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, 12 Months Or Longer, Amortized Cost

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAmortizedCost
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Amortized Cost

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionAmortizedCost
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less Than 12 Months

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAbstract
Namespace Prefix:	ci_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Less Than 12 Months, Amortized Cost

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAmortizedCost
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Debt Securities, Available-For-Sale, Unrealized Loss Position, Accumulated Loss, Before Reclassification To Disposal Group, Assets Held-For-Sale

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLossBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Debt Securities, Available-For-Sale, Unrealized Loss Position, Amortized Cost, Before Reclassification To Disposal Group, Assets Held-For-Sale

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAmortizedCostBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Debt Securities, Available-For-Sale, Unrealized Loss Position, Before Reclassification To Disposal Group, Assets Held For Sale

No definition available.

Name:	ci_DebtSecuritiesAvailableForSaleUnrealizedLossPositionBeforeReclassificationToDisposalGroupAssetsHeldForSale
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922888-210455

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPosition12MonthsOrLongerNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12Months
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without an allowance for credit loss. Includes beneficial interest in securitized financial asset.

Name:	us-gaap_DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsNumberOfPositions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922888-210455

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=121590138&loc=SL82922954-210456

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

Name:	us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionAccumulatedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of investments in debt securities measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.