Condensed Consolidated Statements of Shareholder's Equity (Parentheticals) (Parentheticals) - USD ($) shares in Millions, $ in Millions	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018		Dec. 31, 2017
Treasury Stock, Shares, Held in Trust	1	1	1		1
Treasury Stock, Value, Shares Held In Trust	$ 29	$ 29	$ 31		$ 31
Common Stock, Value, Issued	17	$ 17	17		$ 17
Adoption of new accounting standard	178		(13)	[1]
CVS Health Shareholders' Equity
Adoption of new accounting standard	178		(13)	[1]
Accumulated Other Comprehensive Loss
Adoption of new accounting standard	$ 0		$ (7)	[1]

[1] (3)Reflects the adoption of 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 and an increase to retained earnings of $7 million.