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

- References

No definition available.

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

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

No definition available.

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

This element represents after-tax acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

No definition available.

Name:	ci_BusinessCombinationAcquisitionRelatedCostsAfterTax
Namespace Prefix:	ci_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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

- References

No definition available.

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

The difference between the reacquisition price and the net carrying amount of the extinguished debt recognized currently as a component of income in the period of extinguishment, net of tax.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6401765&loc=d3e13305-112630

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Name:	us-gaap_ExtinguishmentOfDebtGainLossNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256

Name:	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=ci_AccountingStandardsUpdate201609Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementScenarioAxis=us-gaap_RestatementAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ConsolidationItemsAxis=us-gaap_OperatingSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=ci_GlobalHealthBenefitsSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=ci_GlobalSupplementalBenefitsSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=ci_GroupDisabilityAndLifeSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_AllOtherSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: