Consolidated Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions		Total	Cumulative Effect, Period of Adoption, Adjustment		Common Shares	Treasury Shares		Common Stock and Capital Surplus		Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment		Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjustment	Total CVS Health Shareholders' Equity	Total CVS Health Shareholders' Equity Cumulative Effect, Period of Adoption, Adjustment		Noncontrolling Interest
Balance at beginning of period (in shares) at Dec. 31, 2017					1,712	(698)	[1]
Beginning of year balance at Dec. 31, 2017		$ 37,695	$ (13)			$ (37,796)	[1]	$ 32,096	[2]	$ 43,556	$ (6)		$ (165)	$ (7)	$ 37,691	$ (13)		$ 4
Stockholders' Equity [Roll Forward]
Net income (loss)		(596)								(594)					(594)			(2)
Other comprehensive income (Note 13)		274											274		274
Common shares issued to acquire Aetna (in shares)						274
Common shares issued to acquire Aetna		22,484				$ 9,561		12,923							22,484
Stock option activity, stock awards and other (in shares)					8
Stock option activity, stock awards and other		421						421	[2]						421
Purchase of treasury shares, net of ESPP issuances (in shares)	[1]					(1)
Purchase of treasury shares, net of ESPP issuances		7				$ 7	[1]								7
Common stock dividends		(2,045)								(2,045)					(2,045)
Acquisition of noncontrolling interests		329																329
Other decreases in noncontrolling interests		(13)																(13)
Balance at end of period (in shares) at Dec. 31, 2018					1,720	(425)	[1]
End of year balance at Dec. 31, 2018		$ 58,543	178	[3]		$ (28,228)	[1]	45,440	[2]	40,911	178	[3]	102		58,225	178	[3]	318
Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201602Member
Net income (loss)		$ 6,631								6,634					6,634			(3)
Other comprehensive income (Note 13)		917											917		917
Stock option activity, stock awards and other (in shares)					7	2
Stock option activity, stock awards and other		532						532	[2]						532
Purchase of treasury shares, net of ESPP issuances (in shares)	[1]					(2)
Purchase of treasury shares, net of ESPP issuances		(7)				$ (7)	[1]								(7)
Common stock dividends		(2,615)								(2,615)					(2,615)
Other decreases in noncontrolling interests		(9)																(9)
Balance at end of period (in shares) at Dec. 31, 2019					1,727	(425)	[1]
End of year balance at Dec. 31, 2019		$ 64,170	$ (3)			$ (28,235)	[1]	45,972	[2]	45,108	$ (3)		1,019		63,864	$ (3)		306
Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Net income (loss)		$ 7,192								7,179					7,179			13
Other comprehensive income (Note 13)		395											395		395
Stock option activity, stock awards and other (in shares)					6	0
Stock option activity, stock awards and other		541						541	[2]						541
ESPP issuances, net of purchase of treasury shares (in shares)	[1]					2
ESPP issuances, net of purchase of treasury shares		57				$ 57	[1]								57
Common stock dividends		(2,644)								(2,644)					(2,644)
Other decreases in noncontrolling interests		(7)																(7)
Balance at end of period (in shares) at Dec. 31, 2020					1,733	(423)	[1]
End of year balance at Dec. 31, 2020		$ 69,701				$ (28,178)	[1]	$ 46,513	[2]	$ 49,640			$ 1,414		$ 69,389			$ 312

[1] Treasury shares include 1 million shares held in trust for each of the years ended December 31, 2020, 2019 and 2018. Treasury stock includes $29 million related to shares held in trust for each of the years ended December 31, 2020, 2019 and 2018. See Note 1 ‘‘Significant Accounting Policies’’ for additional information.

[2] Common stock and capital surplus includes the par value of common stock of $17 million as of December 31, 2020, 2019 and 2018.

[3] Reflects the adoption of Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers, which resulted in a reduction to retained earnings of $13 million and the adoption of ASU 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income, which resulted in a reduction to accumulated other comprehensive income of $7 million and an increase to retained earnings of $7 million, each during the year ended December 31, 2018.(4)Reflects the adoption of ASU 2016-02, Leases (Topic 842), which resulted in an increase to retained earnings of $178 million during the year ended December 31, 2019.