Summary of Significant Accounting Policies Impact of New Lease Standard On Balance Sheet Line Items (Details) - USD ($) $ in Millions	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets	$ 4,578	$ 4,533	$ 4,581
Total current assets	47,857	45,195	45,243
Property and equipment, net	11,348	11,360	11,349
Operating lease right-of-use assets	20,992	20,987	0
Intangible assets, net	35,147	36,307	36,524
Other assets	4,865	4,525	5,046
Total assets	219,768	216,668	196,456
Accrued expenses	10,443	10,659	10,711
Current portion of operating lease liabilities	1,803	1,803	0
Current portion of long-term debt	3,893	1,267	1,265
Total current liabilities	50,631	45,762	44,009
Long-term operating lease liabilities	18,961	18,832	0
Long-term debt	67,888	71,348	71,444
Deferred income taxes	7,540	7,740	7,677
Other long-term liabilities	2,616	2,262	2,780
Total liabilities	159,762	157,947	137,913
Retained earnings	41,859	41,089	40,911
Total CVS health shareholders' equity	59,686	58,403	58,225
Total shareholders' equity	$ 60,006	58,721	$ 58,543	$ (38,677)	$ (37,695)
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other current assets		(48)
Total current assets		(48)
Property and equipment, net		11
Operating lease right-of-use assets		20,987
Intangible assets, net		(217)
Other assets		(521)
Total assets		20,212
Accrued expenses		(52)
Current portion of operating lease liabilities		1,803
Current portion of long-term debt		2
Total current liabilities		1,753
Long-term operating lease liabilities		18,832
Long-term debt		(96)
Deferred income taxes		63
Other long-term liabilities		(518)
Total liabilities		20,034
Retained Earnings (Accumulated Deficit), Pre-Tax		241
Total CVS health shareholders' equity		178
Total shareholders' equity		$ 178