Variable Interest Entities (Details) $ in Billions	6 Months Ended
Jun. 30, 2019 USD ($) LimitedPartnerships
Securities limited partnerships and real estate limited partnerships [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss related to arrangements with variable interest entity	$ 3.3
Number of limited partnerships defined as variable interest entities \| LimitedPartnerships	135
Carrying amount of assets	$ 1.7
Commitments to contribute additional cash, amount	$ 1.7
Securities limited partnerships and real estate limited partnerships [Member] \| Maximum [Member]
Variable Interest Entity [Line Items]
Non-controlling interest percentage	10.00%
Other asset-backed and corporate securities [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss related to arrangements with variable interest entity	$ 0.6
Carrying amount of assets	0.6
Real estate joint ventures [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss related to arrangements with variable interest entity
Carrying amount of assets
Independent physician associations [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss related to arrangements with variable interest entity
Carrying amount of assets
Health Care Start Up And Growth Stage Companies [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss related to arrangements with variable interest entity
Carrying amount of assets
India Joint Venture [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss related to arrangements with variable interest entity
Carrying amount of assets

Number of individual variable interest entities associated with an aggregate disclosure.

No definition available.

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Namespace Prefix:	ci_
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- Definition

The off-balance sheet obligation to contribute additional cash to limited partnerships.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5747-111685

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5728-111685

+ Details

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Balance Type:	credit
Period Type:	instant

- 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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Period Type:	duration

- Definition

Carrying amount of the assets in the reporting entity's statement of financial position that relate to the reporting entity's variable interest in the Variable Interest Entity (VIE), where the reporting entity is not the VIE's primary beneficiary.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph a
-URI http://asc.fasb.org/extlink&oid=108788376&loc=d3e5728-111685

+ Details

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

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=108788376&loc=SL6759159-111685

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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- Details

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