Taxes on Income	6 Months Ended
Taxes on Income	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Taxes on Income	Taxes on Income The effective income tax rates of 14.5% and 18.9% for the second quarter of 2020 and 2019, respectively, and 15.3% and 13.0% for the first six months of 2020 and 2019, respectively, reflect the impacts of acquisition and divestiture-related costs and restructuring costs, partially offset by the beneficial impact of foreign earnings. In addition, the effective income tax rate for the first six months of 2019 reflects the favorable impact of a $360 million net tax benefit related to the settlement of certain federal income tax matters. In the first quarter of 2019, the Internal Revenue Service (IRS) concluded its examinations of Merck’s 2012-2014 U.S. federal income tax returns. As a result, the Company was required to make a payment of $107 million. The Company’s reserves for unrecognized tax benefits for the years under examination exceeded the adjustments relating to this examination period and therefore the Company recorded a $360 million net tax benefit in the first six months of 2019. This net benefit reflects reductions in reserves for unrecognized tax benefits for tax positions relating to the years that were under examination, partially offset by additional reserves for tax positions not previously reserved for.

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.