Segment Information - Special Item Charges (Benefits) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	18 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026
Pre-tax
Integration and transaction-related costs	$ 34	$ 74	$ 69	$ 290
Charges (benefits) associated with litigation matters	77	0	66	0
Deferred tax expenses (benefits)	0	0	0	0
(Gain) loss on sale of business(es)	(6)	0	(6)	(41)
Total impact from special items, pre-tax	175	203	579	593
After-tax
Integration and transaction-related costs, after-tax	26	56	53	220
Charges (benefits) associated with litigation matters, after-tax	60	0	52	0
Deferred tax expenses (benefits), after-tax	17	17	33	34
(Gain) on sale of businesses, after-tax	(3)	0	(6)	(115)
Total impact from special items, after-tax	153	171	475	400
Strategic Optimization Program
Pre-tax
Strategic optimization program	70	129	450	344	$ 1,199
After-tax
Strategic optimization program, after-tax	$ 53	$ 98	$ 343	$ 261	$ 908

Restructuring Charges, Net Of Tax Expense

No definition available.

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

- Definition

After-tax charges associated with litigation matters that are classified as special items, attributable to the parent. Special items reflect amounts that management does not believe are representative of underlying results of operations.

+ References

No definition available.

+ Details

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

- Definition

+ References

No definition available.

+ Details

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

- Definition

Special Item Charge Benefit Tax Matters

+ References

No definition available.

+ Details

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

- Definition

Special Item Charge Benefit Tax Matters After Tax

+ References

No definition available.

+ Details

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

- Definition

Special Item, Gain (Loss) On Sale Of Business, Before Taxes

+ References

No definition available.

+ Details

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

- Definition

Special Item, Gain (Loss) On Sale Of Business, Net Of Tax

+ References

No definition available.

+ Details

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

- Definition

Sum of before-tax tax amounts classified as special items, attributable to the parent. Special items are excluded from the calculation of 'adjusted income (loss) from operations' because management believes they are not representative of the underlying results of operations. This is generally because the nature and size of these matters are not indicative of our ongoing business operations.

+ References

No definition available.

+ Details

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

- Definition

Sum of after-tax amounts classified as special items, attributable to the parent. Special items are excluded from the calculation of 'adjusted income (loss) from operations' because management believes they are not representative of the underlying results of operations. This is generally because the nature and size of these matters are not indicative of our ongoing business operations.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Pre-tax transaction-related costs primarily consisting of fees for legal, advisory and other professional services, as well as employee costs.

+ References

No definition available.

+ Details

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

- Definition

After-tax transaction-related costs including the impact of tax benefits realized from termination of merger agreement. Transaction-related costs consist primarily of fees for legal, advisory and other professional services as well as employee costs.

+ References

No definition available.

+ Details

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

- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-18

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 5.P.4.b.1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482047/420-10-45-3

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 5.P.3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479823/420-10-S99-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 21
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476148/220-40-50-21

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476148/220-40-50-6

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_RestructuringPlanAxis=ci_StrategicOptimizationProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: