Accounting Standards (Policies)	9 Months Ended
Sep. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements were prepared following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by accounting principles generally accepted in the United States of America (U.S. GAAP) can be condensed or omitted. Balance sheet amounts and operating results for subsidiaries operating outside the U.S. are as of and for the three and nine months ended August 31, 2021 and August 31, 2020.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards	Recently Issued Accounting StandardsIn March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and subsequent amendment to the initial guidance: ASU No. 2021-01, Reference Rate Reform (Topic 848). The new guidance provides temporary optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. Adoption of the guidance is optional and effective as of March 12, 2020, but only available through December 31, 2022. We are currently evaluating the impact that the new guidance will have on our consolidated financial statements and related disclosures, as well as the timing of the potential adoption
Tax Contingencies	Our tax liabilities for uncertain tax positions relate primarily to issues common among multinational corporations. Any settlements or statute of limitations expirations could result in a significant decrease in our uncertain tax positions. Substantially all of these unrecognized tax benefits, if recognized, would impact our effective income tax rate. We do not expect that within the next twelve months any of our uncertain tax positions could significantly decrease as a result of settlements with taxing authorities or the expiration of the statutes of limitations. Our assessments are based on estimates and assumptions that have been deemed reasonable by management, but our estimates of uncertain tax positions and potential tax benefits may not be representative of actual outcomes, and any variation from such estimates could materially affect our financial statements in the period of settlement or when the statutes of limitations expire, as we treat these events as discrete items in the period of resolution. Finalizing audits with the relevant taxing authorities can include formal administrative and legal proceedings, and, as a result, it is difficult to estimate the timing and range of possible changes related to our uncertain tax positions, and such changes could be significant.
Legal Proceedings	A. Legal Proceedings Our non-tax contingencies include, among others, the following: • Product liability and other product-related litigation, which can include injury, consumer, off-label promotion, antitrust and breach of contract claims. • Commercial and other matters, which can include product-pricing claims and environmental claims and proceedings. • Patent litigation, which typically involves challenges to the coverage and/or validity of our patents or those of third parties on various products or processes. • Government investigations, which can involve regulation by national, state and local government agencies in the U.S. and in other countries. Certain of these contingencies could result in losses, including damages, fines and/or civil penalties, and/or criminal charges, which could be substantial. We believe that we have strong defenses in these types of matters, but litigation is inherently unpredictable and excessive verdicts do occur. We do not believe that any of these matters will have a material adverse effect on our financial position. However, we could incur judgments, enter into settlements or revise our expectations regarding the outcome of certain matters, and such developments could have a material adverse effect on our results of operations or cash flows in the period in which the amounts are paid. We have accrued for losses that are both probable and reasonably estimable. Substantially all of these contingencies are subject to significant uncertainties and, therefore, determining the likelihood of a loss and/or the measurement of any loss can be complex. Consequently, we are unable to estimate the range of reasonably possible loss in excess of amounts accrued. Our assessments are based on estimates and assumptions that have been deemed reasonable by management, but the assessment process relies on estimates and assumptions that may prove to be incomplete or inaccurate, and unanticipated events and circumstances may occur that might cause us to change those estimates and assumptions. Amounts recorded for legal and environmental contingencies can result from a complex series of judgments about future events and uncertainties and can rely on estimates and assumptions. The principal matters to which we are a party are discussed below. In determining whether a pending matter is significant for financial reporting and disclosure purposes, we consider both quantitative and qualitative factors in order to assess materiality, such as, among other things, the amount of damages and the nature of any other relief sought in the proceeding, if such damages and other relief are specified; our view of the merits of the claims and of the strength of our defenses; whether the action purports to be a class action and our view of the likelihood that a class will be certified by the court; the jurisdiction in which the proceeding is pending; any experience that we or, to our knowledge, other companies have had in similar proceedings; whether disclosure of the action would be important to a reader of our financial statements, including whether disclosure might change a reader’s judgment about our financial statements in light of all of the information about the company that is available to the reader; the potential impact of the proceeding on our reputation; and the extent of public interest in the matter. In addition, with respect to patent matters, we consider, among other things, the financial significance of the product protected by the patent.
Guarantees and Indemnifications	B. Guarantees and IndemnificationsIn the ordinary course of business and in connection with the sale of assets and businesses, we indemnify our counterparties against certain liabilities that may arise in connection with the transaction or related to activities prior to the transaction. These indemnifications typically pertain to environmental, tax, employee and/or product-related matters and patent-infringement claims. If the indemnified party were to make a successful claim pursuant to the terms of the indemnification, we would be required to reimburse the loss. These indemnifications are generally subject to threshold amounts, specified claim periods and other restrictions and limitations. Historically, we have not paid significant amounts under these provisions and, as of September 30, 2021, recorded amounts for the estimated fair value of these indemnifications were not significant.
Segment Information	Operating Segments We manage our operations through two geographic operating segments: the U.S. and International. Each operating segment has responsibility for its commercial activities. Within each of these operating segments, we offer a diversified product portfolio, including vaccines, parasiticides, anti-infectives, dermatology, medicated feed additives, animal health diagnostics and other pharmaceuticals, for both companion animal and livestock customers. Our chief operating decision maker uses the revenue and earnings of the two operating segments, among other factors, for performance evaluation and resource allocation. Beginning in the first quarter of 2021, certain costs associated with information technology that specifically support our global manufacturing operations, which were previously reported in Other unallocated, are now reported in Corporate. In addition, in the first quarter of 2021, the company realigned certain management responsibilities. These changes did not impact the determination of our operating segments, however they resulted in the reallocation of certain costs between segments. These changes primarily include the following: (i) certain diagnostics costs, which were previously reported in Corporate, are now reported in our U.S. results; and (ii) certain other miscellaneous costs, which were previously reported in our U.S. results, are now reported in Corporate. Other Costs and Business Activities Certain costs are not allocated to our operating segment results, such as costs associated with the following: • Other business activities, includes our Client Supply Services (CSS) contract manufacturing results, our human health business, and expenses associated with our dedicated veterinary medicine research and development organization, research alliances, U.S. regulatory affairs and other operations focused on the development of our products. Other R&D-related costs associated with non-U.S. market and regulatory activities are generally included in the international commercial segment. • Corporate, includes platform functions such as information technology, facilities, legal, finance, human resources, business development, certain diagnostic costs and communications, among others. These costs also include compensation costs and other miscellaneous operating expenses not charged to our operating segments, as well as interest income and expense. •Certain transactions and events such as (i) Purchase accounting adjustments, where we incur expenses associated with the amortization of fair value adjustments to inventory, intangible assets and property, plant and equipment; (ii) Acquisition-related activities, where we incur costs associated with acquiring and integrating newly acquired businesses, such as transaction costs and integration costs; and (iii) Certain significant items, which comprise substantive, unusual items that, either as a result of their nature or size, would not be expected to occur as part of our normal business on a regular basis, such as restructuring charges and implementation costs associated with our cost-reduction/productivity initiatives that are not associated with an acquisition, certain asset impairment charges, certain legal and commercial settlements and the impact of divestiture-related gains and losses. •Other unallocated includes (i) certain overhead expenses associated with our global manufacturing operations not charged to our operating segments; (ii) certain costs associated with finance that specifically support our global manufacturing operations; (iii) certain supply chain and global logistics costs; and (iv) procurement costs. Segment Assets We manage our assets on a total company basis, not by operating segment. Therefore, our chief operating decision maker does not regularly review any asset information by operating segment and, accordingly, we do not report asset information by operating segment.

Accounting Standards (Policies)

9 Months Ended

Sep. 30, 2021

The accompanying unaudited condensed consolidated financial statements were prepared following the requirements of the Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by accounting principles generally accepted in the United States of America (U.S. GAAP) can be condensed or omitted. Balance sheet amounts and operating results for subsidiaries operating outside the U.S. are as of and for the three and nine months ended August 31, 2021 and August 31, 2020.

Recently Adopted Accounting Standards and Recently Issued Accounting Standards

Recently Issued Accounting StandardsIn March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting and subsequent amendment to the initial guidance: ASU No. 2021-01, Reference Rate Reform (Topic 848). The new guidance provides temporary optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions that reference the London Interbank Offered Rate (LIBOR) or another reference rate expected to be discontinued because of reference rate reform. Adoption of the guidance is optional and effective as of March 12, 2020, but only available through December 31, 2022. We are currently evaluating the impact that the new guidance will have on our consolidated financial statements and related disclosures, as well as the timing of the potential adoption

Tax Contingencies

Our tax liabilities for uncertain tax positions relate primarily to issues common among multinational corporations. Any settlements or statute of limitations expirations could result in a significant decrease in our uncertain tax positions. Substantially all of these unrecognized tax benefits, if recognized, would impact our effective income tax rate. We do not expect that within the next twelve months any of our uncertain tax positions could significantly decrease as a result of settlements with taxing authorities or the expiration of the statutes of limitations. Our assessments are based on estimates and assumptions that have been deemed reasonable by management, but our estimates of uncertain tax positions and potential tax benefits may not be representative of actual outcomes, and any variation from such estimates could materially affect our financial statements in the period of settlement or when the statutes of limitations expire, as we treat these events as discrete items in the period of resolution. Finalizing audits with the relevant taxing authorities can include formal administrative and legal proceedings, and, as a result, it is difficult to estimate the timing and range of possible changes related to our uncertain tax positions, and such changes could be significant.

Legal Proceedings

A. Legal Proceedings

Our non-tax contingencies include, among others, the following:

• Product liability and other product-related litigation, which can include injury, consumer, off-label promotion, antitrust and breach of contract claims.

• Commercial and other matters, which can include product-pricing claims and environmental claims and proceedings.

• Patent litigation, which typically involves challenges to the coverage and/or validity of our patents or those of third parties on various products or processes.

• Government investigations, which can involve regulation by national, state and local government agencies in the U.S. and in other countries.

Certain of these contingencies could result in losses, including damages, fines and/or civil penalties, and/or criminal charges, which could be substantial.

We believe that we have strong defenses in these types of matters, but litigation is inherently unpredictable and excessive verdicts do occur. We do not believe that any of these matters will have a material adverse effect on our financial position. However, we could incur judgments, enter into settlements or revise our expectations regarding the outcome of certain matters, and such developments could have a material adverse effect on our results of operations or cash flows in the period in which the amounts are paid.

We have accrued for losses that are both probable and reasonably estimable. Substantially all of these contingencies are subject to significant uncertainties and, therefore, determining the likelihood of a loss and/or the measurement of any loss can be complex. Consequently, we are unable to estimate the range of reasonably possible loss in excess of amounts accrued. Our assessments are based on estimates and assumptions that have been deemed reasonable by management, but the assessment process relies on estimates and assumptions that may prove to be incomplete or inaccurate, and unanticipated events and circumstances may occur that might cause us to change those estimates and assumptions.

Amounts recorded for legal and environmental contingencies can result from a complex series of judgments about future events and uncertainties and can rely on estimates and assumptions.

The principal matters to which we are a party are discussed below. In determining whether a pending matter is significant for financial reporting and disclosure purposes, we consider both quantitative and qualitative factors in order to assess materiality, such as, among other things, the amount of damages and the nature of any other relief sought in the proceeding, if such damages and other relief are specified; our view of the merits of the claims and of the strength of our defenses; whether the action purports to be a class action and our view of the likelihood that a class will be certified by the court; the jurisdiction in which the proceeding is pending; any experience that we or, to our knowledge, other companies have had in similar proceedings; whether disclosure of the action would be important to a reader of our financial statements, including whether disclosure might change a reader’s judgment about our financial statements in light of all of the information about the company that is available to the reader; the potential impact of the proceeding on our reputation; and the extent of public interest in the matter. In addition, with respect to patent matters, we consider, among other things, the financial significance of the product protected by the patent.

Guarantees and Indemnifications

B. Guarantees and IndemnificationsIn the ordinary course of business and in connection with the sale of assets and businesses, we indemnify our counterparties against certain liabilities that may arise in connection with the transaction or related to activities prior to the transaction. These indemnifications typically pertain to environmental, tax, employee and/or product-related matters and patent-infringement claims. If the indemnified party were to make a successful claim pursuant to the terms of the indemnification, we would be required to reimburse the loss. These indemnifications are generally subject to threshold amounts, specified claim periods and other restrictions and limitations. Historically, we have not paid significant amounts under these provisions and, as of September 30, 2021, recorded amounts for the estimated fair value of these indemnifications were not significant.

Segment Information

Operating Segments

We manage our operations through two geographic operating segments: the U.S. and International. Each operating segment has responsibility for its commercial activities. Within each of these operating segments, we offer a diversified product portfolio, including vaccines, parasiticides, anti-infectives, dermatology, medicated feed additives, animal health diagnostics and other pharmaceuticals, for both companion animal and livestock customers. Our chief operating decision maker uses the revenue and earnings of the two operating segments, among other factors, for performance evaluation and resource allocation.

Beginning in the first quarter of 2021, certain costs associated with information technology that specifically support our global manufacturing operations, which were previously reported in Other unallocated, are now reported in Corporate. In addition, in the first quarter of 2021, the company realigned certain management responsibilities. These changes did not impact the determination of our operating segments, however they resulted in the reallocation of certain costs between segments. These changes primarily include the following: (i) certain diagnostics costs, which were previously reported in Corporate, are now reported in our U.S. results; and (ii) certain other miscellaneous costs, which were previously reported in our U.S. results, are now reported in Corporate.

Other Costs and Business Activities

Certain costs are not allocated to our operating segment results, such as costs associated with the following:

• Other business activities, includes our Client Supply Services (CSS) contract manufacturing results, our human health business, and expenses associated with our dedicated veterinary medicine research and development organization, research alliances, U.S. regulatory affairs and other operations focused on the development of our products. Other R&D-related costs associated with non-U.S. market and regulatory activities are generally included in the international commercial segment.

• Corporate, includes platform functions such as information technology, facilities, legal, finance, human resources, business development, certain diagnostic costs and communications, among others. These costs also include compensation costs and other miscellaneous operating expenses not charged to our operating segments, as well as interest income and expense.

•Certain transactions and events such as (i) Purchase accounting adjustments, where we incur expenses associated with the amortization of fair value adjustments to inventory, intangible assets and property, plant and equipment; (ii) Acquisition-related activities, where we incur costs associated with acquiring and integrating newly acquired businesses, such as transaction costs and integration costs; and (iii) Certain significant items, which comprise substantive, unusual items that, either as a result of their nature or size, would not be expected to occur as part of our normal business on a regular basis, such as restructuring charges and implementation costs associated with our cost-reduction/productivity initiatives that are not associated with an acquisition, certain asset impairment charges, certain legal and commercial settlements and the impact of divestiture-related gains and losses.

•Other unallocated includes (i) certain overhead expenses associated with our global manufacturing operations not charged to our operating segments; (ii) certain costs associated with finance that specifically support our global manufacturing operations; (iii) certain supply chain and global logistics costs; and (iv) procurement costs.

Segment Assets

We manage our assets on a total company basis, not by operating segment. Therefore, our chief operating decision maker does not regularly review any asset information by operating segment and, accordingly, we do not report asset information by operating segment.