Significant Accounting Policies - Narrative (Details) shares in Millions, people in Millions		3 Months Ended			12 Months Ended
	Oct. 22, 2020 USD ($)	Dec. 31, 2021 USD ($) store	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Dec. 31, 2021 USD ($) store state Segment	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) store shares	Dec. 31, 2021 shares	Dec. 31, 2021 store	Dec. 31, 2021 member	Dec. 31, 2021 people	Dec. 31, 2021 patient	Dec. 31, 2021 state	Dec. 31, 2021 clinic	Aug. 31, 2019 USD ($)	Jul. 01, 2019 store
Significant Accounting Policies [Line Items]
Number of plan members | people											110
Number of patients served per year (more than) | patient												1,000,000
Number of people served | people											35
Number of reportable segments | Segment					4
Deferred acquisition costs		$ 895,000,000			$ 895,000,000	$ 546,000,000
Depreciation					2,300,000,000	2,100,000,000	$ 1,900,000,000
Store impairment charges					1,358,000,000	0	231,000,000
Goodwill impairment			$ 0	$ 0	431,000,000	0	0
Impairment of intangible assets, indefinite-lived					$ 0	$ 0	0
Assumed interest rates on long-duration group life and long-term care contracts					5.10%	5.10%
HSA balances		2,900,000,000			$ 2,900,000,000	$ 2,700,000,000
Self insurance liabilities		1,100,000,000			$ 1,100,000,000	927,000,000
Pharmacy rebate period					30 days
Health insurer fee					$ 0	1,000,000,000	0
Advertising costs					523,000,000	$ 461,000,000	$ 396,000,000
Treasury shares held in trust (in shares) | shares						1	1	1
Expenses from transactions with related party					52,000,000	$ 56,000,000	$ 32,000,000
Other revenues from transactions with related party					79,000,000	77,000,000	96,000,000
Charitable contribution to CVS Health Foundation					$ 50,000,000	50,000,000	$ 30,000,000
Number of stores, planned closure | store					900		68
U.S. Department of Health and Human Services, ACA Risk Corridor Receivables | Settled Litigation
Significant Accounting Policies [Line Items]
Gain contingency, unrecorded amount						313,000,000									$ 313,000,000
Amount awarded from other party	$ 313,000,000
Former gain contingency, recognized in current period, before tax						307,000,000
Former gain contingency, recognized in current period, net of tax						223,000,000
Heartland Healthcare Services
Significant Accounting Policies [Line Items]
Number of states in which entity operates | state													4
Foreign currency translation adjustments
Significant Accounting Policies [Line Items]
Cumulative translation adjustment from AOCI eliminated upon divestiture					$ 0	0	$ (154,000,000)
Other Insurance Liabilities
Significant Accounting Policies [Line Items]
Liability for unpaid claims		324,000,000			324,000,000	532,000,000
Future policy benefits		416,000,000			416,000,000	462,000,000
Other Long-Term Insurance Liabilities
Significant Accounting Policies [Line Items]
Liability for unpaid claims		1,300,000,000			1,300,000,000	1,500,000,000
Future policy benefits		5,100,000,000			$ 5,100,000,000	$ 5,500,000,000
Minimum
Significant Accounting Policies [Line Items]
Period after date of service a claim is paid					6 months
Assumed interest rates on limited payment pension contracts on large case pension business (in hundredths)					3.00%	3.30%
Interest rate for pension and annuity investment contracts					3.50%	4.10%
Award vesting period					3 years
Minimum | Building, building improvements and leasehold improvements
Significant Accounting Policies [Line Items]
Useful life of property plant and equipment					1 year
Minimum | Fixtures, equipment and internally developed software
Significant Accounting Policies [Line Items]
Useful life of property plant and equipment					3 years
Maximum
Significant Accounting Policies [Line Items]
Lease renewal term					5 years
Period after date of service a claim is paid					48 months
Assumed interest rates on limited payment pension contracts on large case pension business (in hundredths)					11.30%	11.30%
Interest rate for pension and annuity investment contracts					4.80%	5.10%
Award vesting period					5 years
Maximum | Building, building improvements and leasehold improvements
Significant Accounting Policies [Line Items]
Useful life of property plant and equipment					40 years
Maximum | Fixtures, equipment and internally developed software
Significant Accounting Policies [Line Items]
Useful life of property plant and equipment					10 years
Brazil Subsidiary | Discontinued Operations, Disposed of by Sale | Foreign currency translation adjustments
Significant Accounting Policies [Line Items]
Cumulative translation adjustment from AOCI eliminated upon divestiture							$ 154,000,000
Retail/ LTC
Significant Accounting Policies [Line Items]
Number of retail locations (more than) | store									9,900
Number of walk-in medical clinics										1,200				1,200
Store impairment charges		$ 1,400,000,000			$ 1,400,000,000
Goodwill impairment					$ 431,000,000
Number of stores, planned closure | store		900			900		68
Retail/ LTC | Property and equipment
Significant Accounting Policies [Line Items]
Store impairment charges		$ 261,000,000
Retail/ LTC | Brazil Subsidiary | Discontinued Operations, Disposed of by Sale
Significant Accounting Policies [Line Items]
Number of retail locations (more than) | store																50
Health Care Benefits
Significant Accounting Policies [Line Items]
Number of states the Company has submitted regulatory filings for a January 2022 entrance into the individual public health insurance exchange | state					8
Goodwill impairment					$ 0
Health Insurance Product Line
Significant Accounting Policies [Line Items]
Premium deficiency reserve		$ 16,000,000			$ 16,000,000	$ 11,000,000	$ 4,000,000