The period of time prior to a policy anniversary when an annuitization election must occur.

No definition available.

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- Definition

The number of external reinsurers underwriting credit risk ceded by the Company.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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- Definition

Percent of future claim payments reinsured under reinsurance agreement(s), net of existing retrocessional arrangements at the time agreement was made.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

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+ Details

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- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

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-Publisher FASB
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- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

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- Definition

Amount of gain (loss) recognized in income from asset measured at fair value on recurring basis using unobservable input (level 3).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of gain (loss) recognized in income from liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

+ Details

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- Details

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- Details

Name:	us-gaap_CededCreditRiskAxis=ci_BerkshireHathwayLifeInsuranceCompanyOfNebraskaMember
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Period Type:

- Details

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- Details

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- Details

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- Details

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Reinsurance - GMIB Reinsurers (Details) - Guaranteed Minimum Income Benefit [Member] $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) Reinsurers	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) Reinsurers	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Ceded Credit Risk [Line Items]
Annuitization election period			30 days
Number of external reinsurers \| Reinsurers	3		3
Percent of GMIB exposures reinsured	100.00%		100.00%		100.00%
GMIB Assets	$ 808		$ 808		$ 733
GMIB liabilities	781		781		706
Amounts included in shareholders net income for GMIB assets
Amounts included in shareholders net income for GMIB liabilities
Berkshire [Member]
Ceded Credit Risk [Line Items]
GMIB Assets	376		$ 376		341
Berkshire [Member] \| Ceded Credit Risk Secured [Member] \| GMIB Assets [Member]
Ceded Credit Risk [Line Items]
Concentration percentage			100.00%
Sun Life Assurance Company Of Canada [Member]
Ceded Credit Risk [Line Items]
GMIB Assets	230		$ 230		208
Liberty Re (Bermuda) Ltd. [Member]
Ceded Credit Risk [Line Items]
GMIB Assets	$ 202		$ 202		$ 184
Liberty Re (Bermuda) Ltd. [Member] \| Ceded Credit Risk Secured [Member] \| GMIB Assets [Member]
Ceded Credit Risk [Line Items]
Concentration percentage			84.00%