Interim Consolidated Statement of Income (Unaudited) (USD $) In Millions, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Consolidated Statement of Income [Abstract]
Sales	$ 12,151	$ 11,346	$ 23,732	$ 22,768
Costs, Expenses and Other
Materials and production	4,284	4,549	8,343	9,764
Marketing and administrative	3,525	3,175	6,689	6,397
Research and development	1,936	2,179	4,094	4,230
Restructuring costs	668	526	654	814
Equity income from affiliates	(55)	(43)	(193)	(180)
Other (income) expense, net	121	(281)	744	(113)
Total Costs, Expenses and Other	10,479	10,105	20,331	20,912
Income Before Taxes	1,672	1,241	3,401	1,856
Taxes on Income	(382)	461	276	746
Net Income	2,054	780	3,125	1,110
Less: Net Income Attributable to Noncontrolling Interests	30	28	58	59
Net Income Attributable to Merck & Co., Inc.	$ 2,024	$ 752	$ 3,067	$ 1,051
Basic Earnings per Common Share Attributable to Merck & Co., Inc. Common Shareholders	$ 0.65	$ 0.24	$ 0.99	$ 0.34
Earnings per Common Share Assuming Dilution Attributable to Merck & Co., Inc. Common Shareholders	$ 0.65	$ 0.24	$ 0.98	$ 0.33
Dividends Declared per Common Share	$ 0.38	$ 0.38	$ 0.76	$ 0.76