Fair Value - Carrying Value and Fair Value Classified by Level (Details) - Nonrecurring - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Carrying Value
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans	$ 1,047	$ 1,213
Equity securities	145	149
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Investment contracts with a fixed maturity	5	5
Investment contracts without a fixed maturity	322	372
Long-term debt	64,647	68,480
Estimated Fair Value
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans	1,070	1,239
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Investment contracts with a fixed maturity	5	5
Investment contracts without a fixed maturity	371	392
Long-term debt	75,940	74,306
Estimated Fair Value \| Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Investment contracts with a fixed maturity	0	0
Investment contracts without a fixed maturity	0	0
Long-term debt	75,940	74,306
Estimated Fair Value \| Level 2
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans	0	0
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Investment contracts with a fixed maturity	0	0
Investment contracts without a fixed maturity	0	0
Long-term debt	0	0
Estimated Fair Value \| Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Mortgage loans	1,070	1,239
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Investment contracts with a fixed maturity	5	5
Investment contracts without a fixed maturity	371	392
Long-term debt	$ 0	$ 0

Investment Contracts With Fixed Maturity, Fair Value Disclosure.

No definition available.

Name:	cvs_InvestmentContractsWithFixedMaturityFairValueDisclosure
Namespace Prefix:	cvs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Investment Contracts Without A Fixed Maturity, Fair Value Disclosure.

+ References

No definition available.

+ Details

Name:	cvs_InvestmentContractsWithoutFixedMaturityFairValueDisclosure
Namespace Prefix:	cvs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611

+ Details

Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 321
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120269885&loc=SL75117539-209714

+ Details

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

- References

No definition available.

+ Details

Name:	us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of mortgage loans held-for-sale.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: