Elanco Animal Health (ELAN) 10-K 26 Feb 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2023	Feb. 21, 2024	Jun. 30, 2023
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Entity File Number	001-38661
Entity Registrant Name	Elanco Animal Health Inc
Entity Incorporation, State or Country Code	IN
Entity Tax Identification Number	82-5497352
Entity Address, Address Line One	2500 INNOVATION WAY
Entity Address, City or Town	GREENFIELD
Entity Address, State or Province	IN
Entity Address, Postal Zip Code	46140
City Area Code	877
Local Phone Number	352-6261
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	ELAN
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 4.9
Entity Common Stock, Shares Outstanding (in shares)		492,970,011
Documents Incorporated by Reference	Portions of the registrant's definitive proxy materials for its 2024 Annual Meeting of Shareholders are incorporated by reference into Part III hereof.
Document Transition Report	false
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Entity Central Index Key	0001739104

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Audit Information [Abstract]
Auditor Name	Ernst & Young LLP
Auditor Location	Indianapolis, Indiana
Auditor Firm ID	42

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 4,417,000,000	$ 4,411,000,000	$ 4,764,000,000
Costs, expenses and other:
Cost of sales	1,931,000,000	1,913,000,000	2,132,000,000
Research and development	327,000,000	321,000,000	369,000,000
Marketing, selling and administrative	1,285,000,000	1,265,000,000	1,403,000,000
Amortization of intangible assets	548,000,000	528,000,000	556,000,000
Asset impairment, restructuring and other special charges	127,000,000	183,000,000	634,000,000
Goodwill impairment	1,042,000,000	0	0
Interest expense, net of capitalized interest	277,000,000	241,000,000	236,000,000
Other expense, net	75,000,000	32,000,000	5,000,000
Costs, expenses and other	5,612,000,000	4,483,000,000	5,335,000,000
Loss before income taxes	(1,195,000,000)	(72,000,000)	(571,000,000)
Income tax expense (benefit)	36,000,000	6,000,000	(88,000,000)
Net loss	$ (1,231,000,000)	$ (78,000,000)	$ (483,000,000)
Loss per share:
Basic (usd per share)	$ (2.50)	$ (0.16)	$ (0.99)
Diluted (usd per share)	$ (2.50)	$ (0.16)	$ (0.99)
Weighted-average shares outstanding:
Basic (in shares)	492.3	488.3	487.2
Diluted (in shares)	492.3	488.3	487.2

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Loss - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1,231)	$ (78)	$ (483)
Other comprehensive income (loss):
Cash flow hedges, net of taxes	(125)	157	86
Foreign currency translation, net of taxes	293	(419)	(613)
Defined benefit pension and retiree health benefit plans, net of taxes	(42)	79	15
Other comprehensive income (loss), net of taxes	126	(183)	(512)
Comprehensive loss	$ (1,105)	$ (261)	$ (995)

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets
Cash and cash equivalents	$ 352	$ 345
Accounts receivable, net	842	797
Other receivables	168	205
Inventories	1,735	1,538
Prepaid expenses and other	310	394
Total current assets	3,407	3,279
Noncurrent Assets
Goodwill	5,094	5,993
Other intangibles, net	4,494	4,842
Other noncurrent assets	341	378
Property and equipment, net	1,026	999
Total assets	14,362	15,491
Current Liabilities
Accounts payable	270	390
Employee compensation	157	146
Sales rebates and discounts	367	324
Current portion of long-term debt	38	388
Other current liabilities	409	454
Total current liabilities	1,241	1,702
Noncurrent Liabilities
Long-term debt	5,736	5,448
Accrued retirement benefits	184	161
Deferred taxes	567	662
Other noncurrent liabilities	411	229
Total liabilities	8,139	8,202
Commitments and Contingencies
Equity
Common stock, 5,000,000,000 shares authorized, no par value; 492,845,216 and 474,237,738 shares issued and outstanding as of December 31, 2023 and 2022, respectively	0	0
Additional paid-in capital	8,777	8,738
Accumulated deficit	(2,288)	(1,057)
Accumulated other comprehensive loss	(266)	(392)
Total equity	6,223	7,289
Total liabilities and equity	$ 14,362	$ 15,491

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Common stock authorized (in shares)	5,000,000,000	5,000,000,000
Common stock issued (in shares)	492,845,216	474,237,738
Common stock outstanding (in shares)	492,845,216	474,237,738

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Cash Flow Hedges	Foreign Currency Translation	Defined Benefit Plans	Total
Balance at beginning of period (in shares) at Dec. 31, 2020		471,900,000
Balance at beginning of period at Dec. 31, 2020	$ 8,457	$ 0	$ 8,650	$ (496)	$ (61)	$ 360	$ 4	$ 303
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(483)			(483)
Other comprehensive income (loss), net of taxes	(512)				86	(613)	15	(512)
Stock-based compensation activity, net (in shares)		1,200,000
Stock-based compensation activity, net	46		46
Balance at end of period (in shares) at Dec. 31, 2021		473,100,000
Balance at end of period at Dec. 31, 2021	7,508	$ 0	8,696	(979)	25	(253)	19	(209)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(78)			(78)
Other comprehensive income (loss), net of taxes	(183)				157	(419)	79	(183)
Stock-based compensation activity, net (in shares)		1,100,000
Stock-based compensation activity, net	$ 42		42
Balance at end of period (in shares) at Dec. 31, 2022	474,237,738	474,200,000
Balance at end of period at Dec. 31, 2022	$ 7,289	$ 0	8,738	(1,057)	182	(672)	98	(392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(1,231)			(1,231)
Other comprehensive income (loss), net of taxes	126				(125)	293	(42)	126
Stock-based compensation activity, net (in shares)		1,400,000
Stock-based compensation activity, net	$ 39		39
Conversion of tangible equity units (TEUs) into common stock (in shares)		17,200,000
Balance at end of period (in shares) at Dec. 31, 2023	492,845,216	492,800,000
Balance at end of period at Dec. 31, 2023	$ 6,223	$ 0	$ 8,777	$ (2,288)	$ 57	$ (379)	$ 56	$ (266)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash Flows from Operating Activities
Net income (loss)	$ (1,231,000,000)	$ (78,000,000)	$ (483,000,000)
Adjustments to reconcile net loss to cash flows from operating activities:
Depreciation and amortization	694,000,000	682,000,000	716,000,000
Goodwill impairment	1,042,000,000	0	0
Deferred income taxes	(80,000,000)	(57,000,000)	(148,000,000)
Stock-based compensation expense	46,000,000	59,000,000	66,000,000
Asset impairment and write-down charges	32,000,000	81,000,000	345,000,000
Inventory fair value step-up amortization	2,000,000	0	64,000,000
Loss on extinguishment of debt	0	20,000,000	0
Proceeds from interest rate swap settlements	57,000,000	207,000,000	0
Other non-cash operating activities, net	9,000,000	0	11,000,000
Other changes in operating assets and liabilities, net of acquisitions and divestitures:
Receivables	(40,000,000)	14,000,000	(35,000,000)
Inventories	(160,000,000)	(269,000,000)	29,000,000
Other assets	(6,000,000)	(109,000,000)	25,000,000
Accounts payable and other liabilities	(94,000,000)	(98,000,000)	(116,000,000)
Other changes in operating assets and liabilities	0	0	9,000,000
Net Cash Provided by Operating Activities	271,000,000	452,000,000	483,000,000
Cash Flows from Investing Activities
Purchases of property and equipment and software	(140,000,000)	(171,000,000)	(159,000,000)
Purchases of intangible assets	(14,000,000)	(13,000,000)	(38,000,000)
Cash paid for acquisitions, net of cash acquired	(19,000,000)	0	(342,000,000)
Other investing activities, net	4,000,000	5,000,000	9,000,000
Net Cash Used for Investing Activities	(169,000,000)	(179,000,000)	(530,000,000)
Cash Flows from Financing Activities
Proceeds from issuance of long-term debt	0	425,000,000	500,000,000
Repayments of long-term borrowings	(402,000,000)	(677,000,000)	(573,000,000)
Funding related to construction of corporate headquarters	0	(15,000,000)	64,000,000
Other financing activities, net	(6,000,000)	(32,000,000)	(31,000,000)
Net Cash (Used for) Provided by Financing Activities	(83,000,000)	(549,000,000)	210,000,000
Effect of exchange rate changes on cash and cash equivalents	(12,000,000)	(17,000,000)	(31,000,000)
Net increase (decrease) in cash and cash equivalents	7,000,000	(293,000,000)	132,000,000
Cash and cash equivalents at January 1	345,000,000	638,000,000	506,000,000
Cash and cash equivalents at December 31	352,000,000	345,000,000	638,000,000
Revolving credit facility
Cash Flows from Financing Activities
Proceeds from facility	350,000,000	563,000,000	500,000,000
Repayments of facility	(150,000,000)	(813,000,000)	(250,000,000)
Securitization Facility
Cash Flows from Financing Activities
Proceeds from facility	250,000,000	0	0
Repayments of facility	$ (125,000,000)	$ 0	$ 0

Background and Basis of Present

Background and Basis of Presentation	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background and Basis of Presentation	Background and Basis of Presentation Elanco Animal Health Incorporated (collectively, Elanco, the Company, we, us, or our) is a global animal health company that innovates, develops, manufactures and markets products for pets and farm animals. Our diverse, durable portfolio of approximately 200 brands is sold in more than 90 countries and serves animals across many species, primarily: dogs and cats (collectively, pet health) and cattle, poultry, swine, sheep and aqua (collectively, farm animal). Our pet health products are generally sold worldwide to third-party distributors and retailers, as well as directly to veterinarians who typically then sell our products to pet owners. We primarily sell our farm animal products to third-party distributors and to a diverse set of farm animal producers. In recent years, we have expanded our omnichannel presence in both the veterinary clinic and in retail markets, including e-commerce. Elanco was incorporated in Indiana on September 18, 2018, and prior to that was a business unit of Eli Lilly and Company (Lilly). We operate as a single operating segment. Consistent with our operational structure, our Chief Executive Officer (CEO), as the chief operating decision maker (CODM), makes resource allocation and business process decisions globally across our consolidated business. Strategic and resource allocation decisions are managed globally with global functional leaders responsible for determining significant costs/investments and with regional leaders responsible for overseeing the execution of the global strategy. Managing and allocating resources at the global corporate level enables our CEO to assess the overall level of resources available and how to best deploy these resources across functions, product types, regional commercial organizations and research and development projects in line with our overarching long-term corporate-wide strategic goals, rather than on a product or geographic basis. Consistent with this decision-making process, our CEO uses consolidated, single-segment financial information for purposes of evaluating performance, allocating resources, setting incentive compensation targets, as well as forecasting future period financial results. We have prepared the accompanying consolidated financial statements in accordance with accounting principles generally accepted in the United States (GAAP). In our opinion, the financial statements reflect all adjustments (including those that are normal and recurring) that are necessary for fair presentation of the results of operations for the periods shown. All intercompany balances and transactions have been eliminated. In preparing financial statements in conformity with GAAP, we must make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue, expenses and related disclosures at the date of the financial statements and during the reporting period. Actual results could differ from those estimates. We issued our financial statements by filing with the Securities and Exchange Commission (the SEC) and have evaluated subsequent events up to the time of filing. Certain reclassifications of prior year information have been made to conform to the current year's presentation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies The following is a summary of significant accounting policies used in the preparation of the accompanying consolidated financial statements. Estimates and Assumptions The preparation of financial statements in accordance with GAAP requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses. These estimates and underlying assumptions can impact all elements of our consolidated financial statements. Our estimates are often based on several factors, including the facts and circumstances available at the time the estimates are made, historical experience, risk of loss, general economic conditions and trends and the assessment of the probable future outcome. Some of our estimates require significant, difficult or complex judgments, probabilities and assumptions that we believe to be reasonable but that can be inherently uncertain and unpredictable. If our estimates and assumptions are not representative of actual outcomes, our results could be materially impacted. We regularly evaluate our estimates and assumptions and adjust them when facts and circumstances indicate the need for change. Such changes generally would be reflected in our consolidated financial statements in the period they are determined. We apply estimation methodologies consistently from year to year. Revenue We recognize revenue primarily from product sales to customers. Revenue from sales of products is recognized at the point where the customer obtains control of the goods and we satisfy our performance obligation, which is generally once the goods have shipped and the customer has assumed title. For contract manufacturing organization (CMO) arrangements, we recognize revenue over time or at a point in time depending on our evaluation of when the customer obtains control of the promised goods or service. Revenue reflects the total consideration to which we expect to be entitled (i.e., the transaction price), in exchange for products sold, after considering various types of variable consideration, such as rebates, sales allowances, product returns and discounts. Provisions for rebates and discounts, as well as returns, are established in the same period the related sales are recognized. Significant judgments must be made in determining the transaction price for sales of products related to anticipated rebates, discounts and returns. The following describe the most significant of these judgments: Sales Rebates and Discounts • Many of our products are sold and initially invoiced at contractual list prices. Contracts with customers often provide for various rebates and discounts that may differ in each contract. As a consequence, to determine the appropriate transaction price for our product sales, we must estimate any rebates or discounts that ultimately will be due to the customer under the terms of our contracts. The rebate and discount amounts are recorded as a deduction to revenue to arrive at our net product sales during the period in which revenue is recognized. Significant judgment is involved in determining the rebate and discount amounts expected to be payable to a customer. In determining the appropriate accrual amount, we consider our historical experience with similar incentives programs and current sales data and estimates of inventory levels at our channel distributors to evaluate the impact of such programs on revenue. We continually monitor the impact of this experience and adjust our accrual amounts as necessary. Although we accrue a liability for rebates related to these programs at the time the sale is recorded, the rebate related to that sale is typically paid up to six months after the rebate or incentive period expires. Because of this, in any particular period rebate adjustments may incorporate revisions of accruals for several periods. Sales Returns • We estimate a reserve for future product returns based on several factors, including local returns policies and practices, historical returns as a percentage of revenue, an understanding of the reasons for past returns, estimated shelf life by product and estimates of the amount of time between shipment and return. Reserves for sales returns are estimated and recorded in the same period as the underlying revenue recognition as a deduction to arrive at our net product sales and as a liability. Payment terms differ by jurisdiction and customer, but typically range from 30 to 120 days from date of shipment in most of our major jurisdictions. Revenue for our product sales has not been adjusted for the effects of a financing component, as we expect the period between when we transfer control of the product and when we receive payment will be one year or less. Any exceptions are either not material or we collect interest for payments made after the due date. Shipping and handling activities are considered fulfillment activities and are not considered to be a separate performance obligation. We exclude from the measurement of the transaction price all taxes assessed by a governmental authority that are imposed on our sales of product and collected from a customer. Allowance for Doubtful Accounts We provide for an allowance for doubtful accounts, which represents our best estimate of expected lifetime credit losses inherent in our accounts and other receivables portfolios. Our estimates include a continuing credit evaluation of customers' financial condition, trade accounts and other receivables aging and historical loss experience, as well as reasonable and supportable forecasts of future economic conditions. As of December 31, 2023 and 2022, we had an allowance for doubtful accounts of $18 million and $13 million, respectively. Inventories Effective October 1, 2023, we changed our method of accounting for portions of our inventories from the weighted-average cost method to the first-in-first-out (FIFO) method. As of December 31, 2022, inventories accounted for using the weighted-average cost method were approximately 30% of total inventories. We believe the FIFO method is preferable because it is expected to more accurately match revenue with expenses and reflects the current value of inventories on the consolidated balance sheets. Additionally, it will conform the inventory valuation methodology used for the majority of our inventories and improve comparability with industry peers. We concluded this change from the weighted-average cost method to the FIFO method does not have a material effect on the current or prior periods’ financial statements, and therefore, we have not applied the change on a retrospective basis. The impact on the current period financial statements as a result of recording the cumulative effect of this accounting change during the year ended December 31, 2023, was not material. Research and Development Expenses Research and development (R&D) costs are expensed as incurred and relate to the effort associated with the discovery of new knowledge that will be useful in developing a new product or in significantly improving an existing product and the implementation of the research findings. R&D costs include, but are not limited to, compensation and benefits, facilities and overhead expense, clinical trial expense and fees paid to contract research organizations. We may also enter into licensing arrangements with third parties to acquire the rights to in-process research and development (IPR&D). These arrangements typically do not meet the definition of a business combination. In such arrangements, prior to regulatory approval of a product, we record upfront and milestone payments to third parties as expense when the event requiring the upfront or milestone payment occurs. Goodwill and Indefinite-lived Intangible Assets Goodwill represents the excess of the consideration transferred for an acquired business over the assigned fair value of the net assets acquired. Goodwill is not amortized, but is reviewed at least annually for impairment during the fourth quarter, or more frequently if there is a significant change in events or circumstances that indicate the fair value of our single reporting unit is more likely than not less than its carrying amount (i.e., a triggering event). When required, a comparison of fair value to the carrying amount of our single reporting unit is performed to determine the amount of impairment, if any. We begin by assessing qualitative factors to determine whether it is more likely than not that the fair value of our single reporting unit is less than its carrying value. Based on that qualitative assessment, if we conclude it is more likely than not that the fair value of our single reporting unit is less than its carrying value, we conduct a quantitative goodwill impairment test, which involves comparing the estimated fair value of our single reporting unit to its carrying value, including goodwill. We estimate the fair value of our single reporting unit using an income approach, which is a valuation technique that provides an estimate of the fair value of an asset based on market participant expectations of the cash flows an asset would generate over its remaining useful life. If the carrying value of the reporting unit exceeds its estimated fair value, we recognize an impairment loss for the difference. During the third quarter of 2023, there was a sharp increase in long-term treasury rates, and as a result we assessed our long-lived assets for impairment, concluding that a triggering event existed as of September 30, 2023, for certain indefinite-lived assets, including goodwill. Accordingly, we performed an interim quantitative goodwill impairment test, which resulted in a $1,042 million pre-tax impairment charge. The fair value of our single reporting unit was determined using the income approach, based on a discounted cash flow model. Significant management judgment was required in estimating our reporting unit’s fair value, including, but not limited to, estimates and assumptions regarding future cash flows, revenue growth and other profitability measures such as gross margin and EBITDA margin, and the determination of an appropriate discount rate. We made these judgments based on historical experience, relevant market size, historical pricing and expected industry trends. See Note 11. Goodwill and Intangibles for further information. Similar to goodwill, indefinite-lived intangible assets, which primarily represent IPR&D acquired from prior business combinations and to a lesser extent, acquired trade names, are not amortized, but rather are reviewed annually for impairment during the fourth quarter, or more frequently in the event of a triggering event. We utilize the income method for determining the estimated fair value of indefinite-lived intangible assets upon acquiring them in a business combination and as needed for our evaluations of potential impairment. This method is a Level 3 fair value measurement in the fair value hierarchy (see Note 10. Fair Value for further information) and applies a probability weighting that considers the risk of development and commercialization to the estimated future net cash flows derived from projected revenues and estimated costs. These projections are based on factors such as relevant market size, patent protection, historical pricing of similar products and expected industry trends. The estimated future net cash flows are then discounted to the present value using an appropriate discount rate. Acquired IPR&D assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are tested for impairment and, if not impaired, are transferred to marketed products (see below) and amortized over their estimated economic life. Other Long-lived Assets We have a substantial amount of long-lived assets on our consolidated balance sheets, related to both property and equipment and finite-lived intangible assets. Property and equipment: • Property and equipment assets are stated at cost less accumulated depreciation. Assets placed in service are recorded at cost and depreciated using the straight-line method over the estimated useful life of the asset (12 to 50 years for buildings and 3 to 25 years for equipment), except for leasehold improvements, which are depreciated over the shorter of their economic useful life, or their remaining lease term. Repair and maintenance costs that do not extend the useful life of the asset are expensed as incurred. Major replacements and significant improvements that either increase asset values or extend useful lives are capitalized. We assess the recoverability of the carrying value of the property and equipment asset or asset group that includes the property and equipment whenever events or changes in circumstances indicate the carrying amount of the asset may not be fully recoverable. When such indications of a potential impairment exist, we compare the projected undiscounted cash flows to be generated by the asset (or asset group) to its carrying value. If the carrying amount is found to be greater, an impairment charge is recorded equal to the excess of the asset's carrying value over its fair value. In such an event, we also re-evaluate the remaining useful lives of the assets (or asset group) and modify them, as appropriate. Finite-lived intangible assets: • Finite-lived intangible assets primarily relate to marketed products acquired or licensed from third parties and software. Marketed products consist of the amortized cost of the rights to assets acquired in business combinations and approved for marketing in a significant global jurisdiction. The cost basis of marketed products includes both the initial assigned IPR&D value, as well as any associated milestone payments subsequent to the marketed products receiving regulatory approval in a significant global jurisdiction. Software consists of certain costs incurred in connection with obtaining or developing internal-use software, including payroll and payroll-related costs for employees directly associated with the internal-use software projects and direct costs of external resources. Other finite-lived intangible assets consist primarily of the amortized cost of licensed platform technologies, manufacturing technologies and customer relationships. Intangible assets with finite lives are capitalized and amortized over their estimated economic lives, typically ranging from 3 to 20 years. We assess the recoverability of the carrying value of finite-lived intangible assets in the same manner as property and equipment, as described above. Advertising Expenses Costs associated with advertising, including costs for TV, radio and other electronic media and publications, are generally expensed when the related advertising occurs, and are included in marketing, selling and administrative expenses in the consolidated statements of operations. Advertising and promotion expenses for the years ended December 31, 2023, 2022 and 2021, approximated $207 million, $201 million and $248 million, respectively. Foreign Currency Translation Operations in our subsidiaries outside the U.S. are recorded in the functional currency of each subsidiary, which is determined by a review of the environment where each subsidiary primarily generates and expends cash. The results of operations for our subsidiaries outside the U.S., where the U.S. dollar is not the functional currency, are translated from functional currencies into U.S. dollars using the weighted-average currency rate for the period. Assets and liabilities are translated using the period-end exchange rates. The U.S. dollar effects that arise from translating the net assets of these subsidiaries are recorded in other comprehensive income (loss). Foreign currency transaction gains and losses are due to the effect of exchange rate changes on transactions denominated in currencies other than a subsidiary's functional currency and are recognized in other income (expense), net, in the consolidated statements of operations in the period incurred. Transaction losses of $40 million and $28 million, respectively, were recorded during the years ended December 31, 2023 and 2022. We generally identify hyperinflationary markets as those markets whose cumulative inflation rate over a three-year period exceeds 100%. Translation adjustments resulting from the application of hyperinflationary accounting are also recognized in other income (expense), net, in the consolidated statements of operations in the period incurred. Other Significant Accounting Policies Our other significant accounting policies are described in the remaining appropriate notes to the consolidated financial statements. Implementation of New Financial Accounting Pronouncements The following table provides a brief description of an accounting standard adopted in the current year: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2020-04, Reference rate reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting; and related amendments ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. ASU 2021-01 clarifies the scope of Topic 848 so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions. ASU 2022-06 extends the period of time entities can utilize the reference rate reform relief guidance under ASU 2020-04 from December 31, 2022 to December 31, 2024. Adoption of the guidance is optional and effective as of March 12, 2020 through December 31, 2024. Adoption is permitted at any time during the period on a prospective basis. Effective April 1, 2023, and in accordance with the provisions outlined in our underlying credit agreements, we have transitioned the reference rate used in our credit facilities from the London Interbank Offered Rate (LIBOR) to the Secured Overnight Financing Rate (Term SOFR). The change did not have a material impact on our consolidated financial statements. The following table provides a brief description of accounting standards applicable to us that we have not yet adopted: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures ASU 2023-07 is intended to improve disclosure requirements related to reportable segments, primarily through enhanced disclosures about significant segment expenses that are regularly provided to the CODM for purposes of assessing a segment's profit or loss and deciding how to allocate resources. This new standard applies to all public entities, including entities, like us, with a single reportable segment. This new standard is effective for fiscal years beginning after December 31, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. Adoption requires retrospective application. We are currently assessing the impact ASU 2023-07 will have on our consolidated financial statements, including our footnote disclosures. ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures ASU 2023-09 is intended to enhance the transparency and decision usefulness of income tax disclosures by enhancing information about how an entity's operations and related tax risks and its tax planning and operational opportunities affect its tax rate and prospects for future cash flows. The guidance is effective for fiscal years beginning after December 31, 2024, with early adoption permitted. Adoption allows for prospective application, with retrospective application permitted. We are currently assessing the impact ASU 2023-09 will have on our consolidated financial statements, including, but not limited to, our Income Taxes footnote disclosure.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Revenue	Revenue The following table summarizes the activity in our global sales rebates and discounts liability for the years ended December 31: 2023 2022 Beginning balance $ 324 $ 319 Reduction of revenue 722 682 Payments (683) (662) Foreign currency translation adjustments 4 (15) Ending balance $ 367 $ 324 Disaggregation of Revenue The following table summarizes our revenue disaggregated by product category for the years ended December 31: 2023 2022 2021 Pet Health $ 2,104 $ 2,138 $ 2,350 Farm Animal: Cattle 949 944 980 Poultry 765 716 744 Swine 382 384 464 Aqua 175 175 144 Total Farm Animal 2,271 2,219 2,332 Contract Manufacturing (1) 42 54 82 Revenue $ 4,417 $ 4,411 $ 4,764 (1) Represents revenue from arrangements in which we manufacture products on behalf of a third party. The following table summarizes our revenue disaggregated by geographic area for the years ended December 31: 2023 2022 2021 United States $ 1,983 $ 1,965 $ 2,124 International 2,434 2,446 2,640 Revenue $ 4,417 $ 4,411 $ 4,764

Acquisitions, Divestitures and

Acquisitions, Divestitures and Other Arrangements	12 Months Ended
	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Acquisitions, Divestitures and Other Arrangements	Acquisitions, Divestitures and Other Arrangements During 2023 we completed the acquisitions of certain U.S. marketed products, pipeline products, inventory and an assembled workforce from NutriQuest, LLC (NutriQuest) and certain assets including inventory and distribution rights for certain marketed products from NutriQuest Nutricao Animal Ltda (NutriQuest Brazil). In 2021 we completed the acquisition of Kindred Biosciences, Inc. (KindredBio). Each of these transactions was accounted for as a business combination under the acquisition method of accounting. The acquisition method requires, among other things, that assets acquired and liabilities assumed be recognized at their fair values as of the acquisition date. The determination of estimated fair value requires management to make significant estimates and assumptions. The excess of the purchase price over the fair value of the acquired net assets, where applicable, has been recorded as goodwill. NutriQuest U.S. Acquisition On January 3, 2023, we acquired NutriQuest for total purchase consideration of approximately $59 million. NutriQuest is a provider of swine, poultry and cattle nutritional health products to animal producers. This acquisition has helped us expand our existing nutritional health offerings and further our efforts to explore innovative antibiotic alternatives. The composition of the purchase price was as follows: Up-front cash consideration $ 16 Deferred cash consideration paid January 4, 2024 5 Fair value of contingent consideration 38 Total purchase consideration $ 59 Contingent consideration for this acquisition includes up to $85 million of cash consideration payable if specific development, sales and geographic expansion milestones are achieved, as outlined in the asset purchase agreement. The initial fair value of this contingent consideration liability of $38 million was estimated at the acquisition date using a Monte Carlo simulation model, which represented a Level 3 measurement under the fair value measurement hierarchy (see Note 10. Fair Value for further information). The following table summarizes the fair value of assets acquired as of the acquisition date: Inventories $ 3 Intangible assets: Marketed products 29 Acquired IPR&D 9 Other intangible assets 15 Total identifiable assets 56 Goodwill 3 Total consideration transferred $ 59 Other intangible assets consist of customer relationships and trade names. The acquired definite-lived intangible assets are being amortized over a weighted-average estimated useful life of approximately 12 years on a straight-line basis. The estimated fair values of identifiable intangible assets were determined using the income approach. Some of the significant assumptions inherent in the development of these valuations include the estimated net cash flows for each year for each asset or product (including revenues, cost of sales, R&D expenses, marketing, selling and administrative expenses and contributory asset charges), the appropriate discount rate necessary to measure the risk inherent in each future cash flow stream, the life cycle of each asset, the potential regulatory and commercial success risk and competitive trends impacting the asset and each cash flow stream, as well as other factors. The valuation of assets acquired and liabilities assumed was finalized during the fourth quarter of 2023. Revenue attributable to the NutriQuest acquisition for the year ended December 31, 2023, was approximately $19 million. NutriQuest Brazil Acquisition On August 1, 2023, we acquired NutriQuest Brazil for total purchase consideration of $19 million. The composition of the purchase price included cash paid on the closing date of approximately $3 million, with additional consideration payable through 2026 valued at approximately $16 million, a portion of which is contingent upon the continuation of certain terms and conditions set forth in the asset purchase agreement. The following table summarizes the preliminary amounts recognized for assets acquired as of the acquisition date: Inventories $ 3 Definite-lived intangible assets 15 Total identifiable assets 18 Goodwill 1 Total consideration transferred $ 19 The acquired definite-lived intangible assets are being amortized over a weighted-average estimated useful life of approximately nine years on a straight-line basis. The estimated fair values of identifiable intangible assets were determined using the income approach. The purchase price allocation for this acquisition is preliminary as of December 31, 2023, and subject to change, including the valuation of the intangible assets. The final determination of these amounts will be completed as soon as possible but no later than one year from the acquisition date. Neither revenue nor income before taxes included within our consolidated statements of operations from NutriQuest Brazil were material for the year ended December 31, 2023. KindredBio Acquisition On August 27, 2021, we acquired KindredBio, a publicly traded biopharmaceutical company that developed innovative biologics focused on saving and improving the lives of pets, for aggregate cash purchase consideration of $444 million. The acquisition of KindredBio continued our pet health expansion, particularly our presence in dermatology. Prior to this acquisition, in May 2021, we signed an agreement with KindredBio to acquire exclusive global rights to KIND-030, a monoclonal antibody that was being developed for the treatment and prevention of canine parvovirus, a treatment for which we received conditional approval and launched in 2023. We settled the $29 million liability associated with acquiring these rights upon the closing of our acquisition of KindredBio in August 2021. The following table summarizes the fair value of assets acquired and liabilities assumed as of the acquisition date: Cash and cash equivalents $ 31 Other net working capital 13 Property and equipment 33 Intangible assets, primarily acquired IPR&D 333 Deferred income taxes, net (30) Total identifiable net assets 380 Goodwill 35 Settlement of liability related to previous license agreement 29 Total consideration transferred $ 444 The valuation of assets acquired and liabilities assumed was finalized during the third quarter of 2022. Property and equipment was mostly comprised of land, buildings, equipment and construction in progress. The estimated fair values of acquired IPR&D were determined using the income approach. Some of the significant assumptions inherent in the development of these valuations included the estimated net cash flows for each year for each IPR&D asset acquired, the appropriate discount rate necessary to measure the risk inherent in each future cash flow stream, the life cycle of each asset, the potential regulatory and commercial success risk and competitive trends impacting the asset and each cash flow stream, as well as other factors. The goodwill recognized from this acquisition was primarily attributable to KindredBio's assembled workforce and anticipated synergies. The majority of goodwill associated with this acquisition is not deductible for tax purposes. Revenue and loss from KindredBio included in the consolidated statements of operations since the date of acquisition were not material. Divestitures Microbiome R&D platform carve-out In April 2022, we signed an agreement to transfer assets associated with our microbiome R&D platform to a newly created, independent biopharmaceutical company, BiomEdit, focused on developing solutions for animal and human health. As part of the agreement, we retained a non-voting, minority stake in the company. Assets transferred included intellectual property and laboratory equipment. The book values of those assets were not material. In addition, we entered into transitional services agreements with the company for certain services. During the year ended December 31, 2022, we recorded a gain on the disposal of approximately $3 million. Shawnee and Speke divestitures During 2021, as part of our strategy to optimize our manufacturing footprint, we announced an agreement with TriRx Pharmaceuticals (TriRx) to sell our manufacturing sites in Shawnee, Kansas (Shawnee) and Speke, U.K. (Speke), including the planned transfer of approximately 600 employees. In connection with these arrangements, we also entered into long-term manufacturing and supply agreements, under which TriRx is to manufacture existing Elanco products at both sites subsequent to the closing of the transactions. In August 2021 and February 2022, we completed the sales of our Shawnee and Speke sites, respectively. Based on the original terms of the sales agreements, we anticipated receiving cash consideration from TriRx over a three-year period, and during the year ended December 31, 2022, we received cash proceeds of $13 million from TriRx related to the sales of Shawnee and Speke. In May 2023, we entered into amendments to the agreements (the amended agreement) which effectively restructured the payment schedule related to the remaining amount owed. As of December 31, 2023, our remaining net receivable balance from TriRx related to the sales of Shawnee and Speke, and under the amended agreement, was $69 million, of which $66 million was received in February 2024, with the remaining $3 million due in August 2024. Further, upon closing the sale of the Speke site in 2022, we recorded a contract asset of $55 million for the favorable supply agreement. During the fourth quarter of 2023, we determined that a forecasted decline in cash flows associated with the contract asset represented an indicator of impairment, which required us to perform a test for recoverability. In performing this assessment, we compared the expected undiscounted cash flows associated with the contract asset to its carrying value, determining that the asset was impaired as of December 31, 2023. Based on a comparison of the estimated fair value of the contract asset to its carrying value, we recorded a $26 million impairment charge. The remaining net book value of $14 million related to this contact asset as of December 31, 2023, was included in prepaid expenses and other and other noncurrent assets on our consolidated balance sheets. Our fair value assessment for the supply agreement was estimated, both upon the initial determination in 2022 and as part of our 2023 impairment assessment, using a combined income and market approach, which incorporated Level 3 inputs. BexCaFe Arrangement In June 2022, we signed a license agreement with BexCaFe, LLC (BexCaFe) for the development and commercialization of products related to Bexacat , an oral treatment intended to reduce glucose levels in diabetic cats. BexCaFe held the rights to the compound through a license agreement with similar terms and conditions. Since signing this license agreement, we have incurred, and will continue to incur, all development and regulatory costs associated with the products. We determined that BexCaFe represented a variable interest entity and that we are the primary beneficiary because the terms of the license give us the power to direct the activities that most significantly impact BexCaFe's economic performance. As a result, we consolidated BexCaFe, a development-stage company with no employees that did not meet the definition of a business, as of the date we signed the license agreement. Upon initial consolidation of BexCaFe, we measured an IPR&D asset at its fair value of $59 million and recorded liabilities totaling $59 million, which included contingent consideration of $49 million based on the fair value of estimated future milestone payments and sales royalties owed under the license agreement. The initial fair value of the contingent payments was calculated based on an income approach, with payments adjusted for probability of success and discounted to a present value. There is no minimum payout due on the contingent consideration and the maximum payout related to sales royalties is unlimited. Since BexCaFe did not meet the definition of a business, no goodwill was recorded, and immediately after initial consolidation, we expensed the IPR&D asset because we concluded it did not have an alternative future use. During the year ended December 31, 2023, we paid $13 million to BexCaFe in connection with development/regulatory milestones achieved upon U.S. Food and Drug Administration (FDA) approval of the original new animal drug application for Bexacat

Asset Impairment, Restructuring

Asset Impairment, Restructuring and Other Special Charges	12 Months Ended
	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Asset Impairment, Restructuring and Other Special Charges	Asset Impairment, Restructuring and Other Special Charges In recent years, we have incurred substantial costs associated with restructuring programs and cost-reduction initiatives designed to achieve a flexible and competitive cost structure. These restructuring activities have primarily included charges associated with facility rationalization and workforce reductions. In connection with recent acquisitions, including the acquisition of Bayer Animal Health, we have also incurred costs associated with executing transactions and integrating acquired operations. In addition, we have incurred costs to stand up our organization as an independent company. All operating functions can be impacted by these actions; therefore, non-cash impairment charges have also been incurred as a result of revised fair value projections and/or determinations to no longer utilize certain assets on an ongoing basis. Determinations of fair value can result from a complex series of judgments and rely on estimates and assumptions. Components of asset impairment, restructuring and other special charges for the years ended December 31 were as follows: 2023 2022 2021 Restructuring charges (credits) (1) $ — $ (7) $ 110 Acquisition related charges (2) 93 105 162 Non-cash and other items: Asset impairment (3) 32 81 350 Other special charges (4) 2 4 12 Total expense $ 127 $ 183 $ 634 (1) Restructuring credits in 2022 related to adjustments resulting from the reversal of severance accruals associated with 2021 restructuring programs, resulting from final negotiations and certain restructured employees filling open positions. Restructuring charges in 2021 primarily represented employee termination costs for restructuring programs announced and initiated in January and November 2021. These costs were partially offset by the reversal of severance accruals associated with prior restructuring programs during the period. (2) Acquisition related charges primarily included transaction costs directly related to acquiring businesses, such as expenditures for banking, legal, accounting, consulting and other similar services, integration charges inclusive of system and process integration and product transfers, and independent company stand-up costs related to the implementation of new systems, programs and processes. (3) Asset impairments during 2023 included a $26 million write-down of a contract asset related to a long-term manufacturing and supply agreement initially recorded upon the completion of the sale of our Speke site (see Note 4. Acquisitions, Divestitures and Other Arrangements for further discussion on this item) and a write-down of certain indefinite-lived intangible assets, principally due to increases in the relevant discount rates. Asset impairments during 2022 included a charge of $59 million related to the write-off of an IPR&D asset with no alternative future use licensed from BexCaFe and a $22 million charge related to the finalization of the write-down upon sale of the Speke site. Asset impairments in 2021 included write-downs of certain IPR&D and marketed products assets that were subject to product rationalization, as well as write-downs of assets ultimately sold related to the Shawnee and Speke sites. Also included in 2021 are charges recorded to write-down assets in connection with restructuring programs. (4) Other special charges in 2021 primarily represented $10 million of litigation settlements. The following table summarizes the activity in our reserves established in connection with restructuring activities: Balance at December 31, 2021 $ 126 Reserve adjustment (9) Cash paid (79) Foreign currency translation adjustments (2) Balance at December 31, 2022 36 Cash paid (29) Balance at December 31, 2023 $ 7

Inventories

Inventories	12 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Inventories	Inventories We state all inventories at the lower of cost and net realizable value. We value a majority of our inventories using the FIFO method, although at December 31, 2023 and 2022, $295 million and $288 million, respectively, of our total inventories were valued using the last-in, first-out (LIFO) method. Inventories at December 31 consisted of the following: 2023 2022 Finished products $ 857 $ 783 Work in process 814 683 Raw materials and supplies 128 130 Total 1,799 1,596 Decrease to LIFO cost (64) (58) Inventories $ 1,735 $ 1,538

Equity

Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Equity	Equity Elanco had 5.0 billion ordinary shares authorized, with approximately 492.8 million issued and outstanding as of December 31, 2023. Elanco also had 1.0 billion preferred shares, no par value, authorized (with none issued or outstanding) as of December 31, 2023. Tangible Equity Unit (TEU) Offering

Debt

Debt	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Debt	Debt Long-term debt as of December 31 consisted of the following: 2023 2022 Incremental Term Facility due 2025 $ 175 $ 175 Incremental Term Facility due 2028 489 494 Incremental Term Facility due 2029 247 249 Term Loan B due 2027 3,838 3,881 Revolving Credit Facility (1) 200 — Securitization Facility (2) 125 — 4.272% Senior Notes due 2023 (3) — 344 4.900% Senior Notes due 2028 (4) 750 750 TEU Amortizing Notes due 2023 (5) — 7 Unamortized debt issuance costs (50) (64) 5,774 5,836 Less current portion of long-term debt 38 388 Total long-term debt $ 5,736 $ 5,448 (1) Our Revolving Credit Facility provides up to $750 million in borrowing capacity (with incremental capacity if certain conditions are met), bears interest at Term SOFR plus 2.10% and matures in August 2025. In February 2024, we drew an additional $50 million on our Revolving Credit Facility to fund working capital and other operational needs. (2) In August 2023 we entered into a new secured term facility that is secured and collateralized by our U.S. Net Eligible Receivables Balance (see below for further information). In January 2024, we drew an additional $50 million on our Securitization Facility to fund working capital and other operational needs. (3) We redeemed the 4.272% Senior Notes due 2023 in full in August 2023 (see below for further information). (4) Subsequent to issuance in August 2018, the 4.900% Senior Notes due 2028 have been subject to interest rate increases related to credit rating agency downgrades. As of December 31, 2023, these notes bear interest at a rate of 6.650%. (5) The TEU Amortizing Notes due 2023 matured on February 1, 2023 (see Note 7. Equity for further information). Future required principal payments on our outstanding indebtedness for each of the next five years and thereafter, as of December 31, 2023, were as follows: 2024 $ 50 2025 425 2026 175 2027 3,718 2028 1,221 2029 and thereafter 235 Total obligations and commitments 5,824 Unamortized debt issuance costs (50) Total debt $ 5,774 As of December 31, 2023, approximately 78% of our long-term indebtedness bore interest at a fixed rate, including variable-rate converted to fixed-rate through the use of interest rate swaps (see Note 9. Financial Instruments for further information). Cash payments for interest during the years ended December 31 were as follows: 2023 2022 2021 Interest paid $ 379 $ 266 $ 221 Term Loan B and Revolving Credit Facility In connection with our acquisition of Bayer Animal Health in 2020, we entered into our Term Loan B facility, which bears interest at a floating rate of Term SOFR plus 175 basis points and is payable in quarterly installments through its maturity on August 1, 2027. Simultaneously, we entered into our Revolving Credit Facility, which provides us with a source of liquidity for certain operating activities and for additional flexibility to finance capital investments, business development activities, repayments of debt and other cash requirements. Our Term Loan B and Revolving Credit Facility are secured by a significant portion of our assets. There are two financial maintenance covenants which are solely for the benefit of lenders under the Revolving Credit Facility. There are no financial maintenance covenants for the benefit of the Term Loan B facility, and the lenders under the Term Loan B facility have no enforcement rights with respect to the financial maintenance covenants for the Revolving Credit Facility. The first financial maintenance covenant for the Revolving Credit Facility requires us to maintain a net total leverage ratio level (which is not subject to step-downs) as of the end of each quarter. The required level of this covenant is based on closing date pro forma net leverage and pro forma adjusted earnings before interest, taxes, depreciation and amortization (EBITDA) not to exceed 7.71 to 1.00 of our pro forma adjusted EBITDA for the preceding four fiscal quarters. The second financial maintenance covenant for the Revolving Credit Facility requires us to maintain a ratio of pro forma adjusted EBITDA to cash interest expense of no less than 2.00 to 1.00, tested as of the end of each fiscal quarter. We were in compliance with all of our debt covenants as of December 31, 2023. 2023 Financings On August 3, 2023, we entered into a new secured term facility (the Securitization Facility) that is secured and collateralized by our U.S. accounts receivable, subject to certain adjustments (defined as the Net Eligible Receivables Balance within the applicable agreement). The terms of the agreement result in an amount of our U.S. accounts receivable, equivalent to the outstanding balance of the Securitization Facility at any point in time, being pledged to the lender as collateral for the borrowings. Of the maximum borrowing capacity under the Securitization Facility of $300 million, $250 million was drawn on August 3, 2023, based on our borrowing capacity on that date. Our borrowing capacity under the Securitization Facility is subject to fluctuation monthly based on the level of our borrowing base as reported to the lender, which is correlated to our U.S. Net Eligible Receivables Balances. The Securitization Facility requires monthly interest payments over its three-year term at a variable rate based on Term SOFR plus 125 basis points. The full, outstanding balance of the Securitization Facility is due on July 31, 2026. We utilized the proceeds from the Securitization Facility, in addition to a $100 million draw on our Revolving Credit Facility, to redeem in full the 4.272% Senior Notes due 2023 on August 7, 2023. Subsequent to our initial $250 million draw on the Securitization Facility, $125 million was repaid, resulting in a balance of $125 million outstanding as of December 31, 2023. In January 2024, we drew an additional $50 million on our Securitization Facility to fund working capital and other operational needs. The Securitization Facility includes various covenants specific to the underlying composition of our U.S. accounts receivables portfolio, all of which we were in compliance with as of December 31, 2023. 2022 Financings In April 2022, we entered into an incremental assumption agreement which provides for an incremental term facility with an aggregate principal amount of $250 million maturing on April 19, 2029 (the Incremental Term Facility due 2029). The Incremental Term Facility due 2029 bears interest at Term SOFR, including a credit spread adjustment, plus 175 basis points and is payable in quarterly installments of principal and interest with a final balloon payment due at maturity. The terms of the Incremental Term Facility due 2029 are generally consistent with the terms of our Term Loan B and Revolving Credit Facility. In June 2022, we entered into an incremental assumption agreement which provides for an incremental term facility with an aggregate principal amount of $175 million maturing on June 30, 2025 (the Incremental Term Facility due 2025). The Incremental Term Facility due 2025 bears interest at Term SOFR, including a credit spread adjustment, plus 175 basis points and is payable in full at maturity. The terms of the Incremental Term Facility due 2025 are generally consistent with the terms of our Term Loan B and Revolving Credit Facility. 2021 Financing In August 2021, we entered into an incremental assumption agreement which provides for an incremental term facility with an aggregate principal amount of $500 million maturing on August 12, 2028 (the Incremental Term Facility due 2028). The incremental term facility bears interest at Term SOFR plus 175 basis points and is payable in quarterly installments of principal and interest with a final balloon payment due at maturity. The terms of the Incremental Term Facility due 2028 are generally consistent with the terms of our Term Loan B and Revolving Credit Facility. Senior Notes In August 2018, we issued $750 million of 4.272% Senior Notes due August 28, 2023 and $750 million of 4.900% Senior Notes due August 28, 2028. The interest rate payable on each series of Senior Notes has been subject to adjustment in the event of credit rating agency downgrades, which last occurred in April 2023. The indenture that governs the Senior Notes contains covenants that limit our ability to incur liens or engage in sale-leaseback transactions. The indenture also contains restrictions on our ability to consolidate, merge or sell substantially all of our assets, in addition to other customary terms. We were in compliance with all such covenants under the indenture governing the Senior Notes as of December 31, 2023. In April 2022, we completed a tender offer and retired $406 million in aggregate principal amount of our 4.272% Senior Notes due August 28, 2023, resulting in a debt extinguishment loss of approximately $17 million, which was recognized in interest expense, net of capitalized interest in the consolidated statements of operations. As discussed above, on August 7, 2023, we utilized the proceeds from the Securitization Facility, in addition to a $100 million draw on our Revolving Credit Facility, to redeem in full the remaining outstanding 4.272% Senior Notes due 2023. This early redemption satisfied all obligations and commitments related to the 4.272% Senior Notes due 2023.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Financial Instruments	Financial Instruments To manage our exposure to market risks, such as changes in foreign currency exchange rates and interest rates, we have entered into various derivative transactions. We formally assess, designate and document, as a hedge of an underlying exposure, each qualifying derivative instrument that will be accounted for as an accounting hedge at inception. We also assess at least quarterly thereafter whether the financial instruments used in the hedging transaction are effective at offsetting changes in either the fair values or cash flows of the underlying exposures. Derivative cash flows are principally classified in the operating activities section of the consolidated statements of cash flows, consistent with the underlying hedged item. Further, we do not offset derivative assets and liabilities on the consolidated balance sheets. Our outstanding positions are discussed below. Derivatives Not Designated as Hedges We may enter into foreign exchange forward or option contracts to reduce the effect of fluctuating currency exchange rates. Foreign currency derivatives used for hedging are put in place using the same or like currencies and duration as the underlying exposures and are recorded at fair value with the gain or loss recognized in other expense, net in the consolidated statements of operations. Forward contracts generally have maturities not exceeding 12 months. As of December 31, 2023 and 2022 , we had outstanding foreign exchange contracts with aggregate notional amounts of $891 million and $784 million, respectively. The amount of net gains (losses) on derivative instruments not designated as hedging instruments, recorded in other expense, net for the years ended December 31, were as follows: 2023 2022 2021 Foreign exchange forward contracts (1) $ 7 $ (12) $ (35) (1) These amounts were substantially offset in other expense, net by the effect of changing exchange rates on the underlying foreign currency exposures. Derivatives Designated as Hedges – Net investment hedges In September 2023 we entered into a series of cross-currency fixed interest rate swaps to help mitigate the impact of currency fluctuations on our operations in Switzerland with a combined 1,000 million CHF notional amount with tenors in 2026 and 2027. These instruments were determined to be, and were designated as, effective economic hedges of net investments in our CHF denominated net assets. The fair values of these instruments were estimated based on quoted market values of similar hedges and are classified as Level 2 in the fair value hierarchy (see Note 10. Fair Value for further information). Gains or losses related to these instruments due to spot rate fluctuations are recorded as cumulative translation adjustments as a component of other comprehensive income (loss). Gains and losses will remain in accumulated other comprehensive income (loss) until either the sale or substantial liquidation of the hedged subsidiary. The amount of losses on net investment hedges, net of tax, recorded in other comprehensive income (loss), for the year ended December 31, was as follows: 2023 Cross-currency fixed interest rate swaps $ (72) For the year ended December 31, 2023, these instruments also generated $9 million of interest income, which is included as a contra interest expense, net of capitalized interest in our consolidated statements of operations. Derivatives Designated as Hedges – Interest rate swaps To manage our exposure to variable interest rate risk, we utilize interest rate swap contracts to effectively convert our variable-rate debt into fixed-rate debt. We recognize any differences between the variable interest rate payments and the fixed interest rate settlements with the swap counterparties as an adjustment to interest expense, net of capitalized interest over the life of the swaps. We have designated our interest rate swaps as cash flow hedges and record them at fair value on the consolidated balance sheets. Changes in the fair value of the hedges are recognized in other comprehensive income (loss) and reclassified into earnings through interest expense, net of capitalized interest at the time earnings are affected by the hedged transaction. Fair value is estimated based on quoted market values of similar hedges and is classified as Level 2 in the fair value hierarchy. We had outstanding forward-starting interest rate swaps with aggregate notional amounts of $3,800 million and $3,050 million as of December 31, 2023 and December 31, 2022, respectively. In March 2023, we entered into new interest rate swap agreements with a combined notional amount of $1,000 million, which prior to the interest rate swap restructuring in September 2023 discussed below, were set to become effective on October 1, 2023, following the maturity of certain swaps with the same combined notional amount. Additionally, on May 1, 2023, we entered into new interest rate swap agreements with a combined notional amount of $750 million, which became effective on June 1, 2023, and mature in August 2028. As of December 31, 2023, our outstanding forward-starting interest rate swap instruments had maturities ranging between 2026 and 2028. The amounts of gains on interest rate swap contracts, net of tax, recorded in accumulated other comprehensive loss, for the years ended December 31, were as follows: 2023 2022 2021 Forward-starting interest rate swaps $ — $ 209 $ 58 The amounts of gains (losses) reclassified from accumulated other comprehensive loss and recognized into earnings through interest expense, net of capitalized interest for the years ended December 31, were as follows: 2023 2022 2021 Forward-starting interest rate swaps $ 125 $ 35 $ (28) Over the next 12 months, we expect to reclassify a gain of $90 million from accumulated other comprehensive loss into interest expense, net of capitalized interest related to our interest rate swaps. In April and September 2022, we took advantage of market opportunities to restructure our interest rate swap portfolio by unwinding the previously existing swaps and simultaneously entering into new agreements with the same notional amounts and covering the same tenors. As a result, we received cash settlements of $207 million during 2022, in aggregate. In September 2023, we took further advantage of market opportunities to restructure $3,050 million of our interest rate swap portfolio by unwinding existing swaps, including the $1,000 million of aforementioned swaps that had not yet taken effect, and simultaneously entering into new agreements with the same notional amounts and tenors extending through 2026. As a result, we received cash settlements of $57 million in the aggregate. Cash proceeds from these interest rate swap settlements were included in net cash from operating activities in the consolidated statements of cash flows for the years ended December 31, 2023 and 2022, and will continue to be reclassified to interest expense, net of capitalized interest over the remaining period of the swaps' original tenors. Additionally, as a result of the April 2022 interest rate swap settlement, we reclassified $17 million of a stranded tax benefit from accumulated other comprehensive loss to income tax expense, based on our policy to reclassify income tax effects from accumulated other comprehensive loss using the portfolio approach. As of December 31, 2023, when factoring in the $3,800 million of variable rate debt converted to fixed-rate through the use of interest rate swaps (excluding the expected future reclassifications to interest expense, net of capitalized interest related to past interest rate swap settlements), the weighted-average effective interest rate on our outstanding indebtedness was 6.40%.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Fair Value	Fair Value Fair value is defined as the exchange price that would be received to sell an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Fair value measurements are based on a framework that utilizes the inputs market participants use to determine the fair value of an asset or liability and establishes a fair value hierarchy to prioritize those inputs. Level 1 fair value measurements are based on quoted prices in active markets for identical assets or liabilities. We determine our Level 2 fair value measurements based on a market approach using quoted market values or significant other observable inputs for identical or comparable assets or liabilities. Our Level 3 fair value measurements, which include the value of contingent consideration as of December 31, 2023, are based on unobservable inputs based on little or no market activity. The following table summarizes the fair value information at December 31, 2023 and 2022, for assets and liabilities measured at fair value on a recurring basis in the respective balance sheet line items, as well as long-term debt, for which fair value is disclosed on a recurring basis: Fair Value Measurements Using Financial statement line item Carrying Amount Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Fair Value December 31, 2023 Recurring fair value measurements Prepaid expenses and other - derivative instruments $ 65 $ — $ 65 $ — $ 65 Other current liabilities - derivative instruments (63) — (63) — (63) Other current liabilities - contingent consideration (9) — — (9) (9) Other noncurrent liabilities - derivative instruments (132) — (132) — (132) Other noncurrent liabilities - contingent consideration (31) — — (31) (31) Financial instruments not carried at fair value Long-term debt, including current portion (5,824) — (5,825) — (5,825) December 31, 2022 Recurring fair value measurements Prepaid expenses and other - derivative instruments $ 90 $ — $ 90 $ — $ 90 Other noncurrent assets - derivative instruments 10 — 10 — 10 Other noncurrent assets - investments with readily determinable fair value 7 7 — — 7 Other current liabilities - derivative instruments (64) — (64) — (64) Financial instruments not carried at fair value Long-term debt, including current portion (5,900) — (5,711) — (5,711) Cash and cash equivalents include cash on hand and all highly liquid investments with original maturities at the time of purchase of three months or less. The carrying values of cash and cash equivalents, accounts and other receivables, accounts payable, employee compensation and other current liabilities are a reasonable estimate of their fair values due to the short-term nature of these assets and liabilities. We also had investments without readily determinable fair values and equity method investments, which were classified as other noncurrent assets on the consolidated balance sheets totaling $26 million and $27 million as of December 31, 2023 and 2022 , respectively. These investments are not recorded at fair value on a recurring basis, and as such, are not included in the fair value table above. Of the total value of the contingent consideration liabilities at December 31, 2023, $34 million related to our acquisition of NutriQuest during the first quarter of 2023 (see Note 4. Acquisitions, Divestitures and Other Arrangements for further information). We may pay up to $85 million in cash consideration related to this acquisition, which is contingent upon the achievement of specific development, sales and geographic expansion milestones, as outlined in the asset purchase agreement. The fair values of these liabilities at December 31, 2023, were estimated using the Monte Carlo simulation model, consisting of Level 3 inputs not observable in the market, including estimates relating to revenue forecasts, discount rates and volatility.

Goodwill and Intangibles

Goodwill and Intangibles	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Goodwill and Intangibles Goodwill The following table summarizes the changes in the carrying amount of goodwill: December 31, 2021 $ 6,172 Additions related to the KindredBio acquisition 3 Goodwill associated with Speke divestiture (3) Foreign currency translation adjustments (179) December 31, 2022 5,993 Additions related to acquisitions 4 Impairment charge (1,042) Foreign currency translation adjustments 139 December 31, 2023 $ 5,094 As disclosed previously, there was a sharp increase in long-term treasury rates during the third quarter of 2023, and as a result, we assessed our long-lived assets for impairment, concluding that a triggering event existed as of September 30, 2023, for certain indefinite-lived assets, including goodwill. Accordingly, we performed an interim quantitative goodwill impairment test, which resulted in a $1,042 million pre-tax impairment charge. The fair value of our single reporting unit was determined using the income approach, based on a discounted cash flow model. Significant management judgment was required in estimating our reporting unit’s fair value, including, but not limited to, estimates and assumptions regarding future cash flows, revenue growth and other profitability measures such as gross margin and EBITDA margin; and the determination of an appropriate discount rate. We made these judgments based on historical experience, relevant market size, historical pricing and expected industry trends. We reevaluated our long-lived assets for impairment at December 31, 2023, and concluded no impairment indicators existed with respect to our indefinite-lived assets, including goodwill. While we believe our estimates and assumptions underlying our interim quantitative goodwill impairment test were reasonable in view of all available information, and while no further impairment charges were recorded during the fourth quarter of 2023, future changes in our discount rate, whether driven by increases in long-term treasury rates or other factors, or future changes in other significant assumptions or the use of alternative estimates and assumptions, could have a significant impact on the estimated fair value of our reporting unit, exposing us to further goodwill impairment losses. No impairments to the carrying value of goodwill were recorded during the years ended December 2022 and 2021. Other Intangible Assets The gross amount of intangible assets and related accumulated amortization, as of December 31, were as follows: 2023 2022 Description Carrying Amount, Gross Accumulated Amortization Carrying Amount, Net Carrying Amount, Gross Accumulated Amortization Carrying Amount, Net Finite-lived intangible assets: Marketed products $ 6,947 $ (2,982) $ 3,965 $ 6,561 $ (2,275) $ 4,286 Software 257 (111) 146 310 (135) 175 Other 71 (35) 36 47 (31) 16 Total finite-lived intangible assets 7,275 (3,128) 4,147 6,918 (2,441) 4,477 Indefinite-lived intangible assets: Acquired IPR&D 339 — 339 359 — 359 Trade names 8 — 8 6 — 6 Total intangible assets: $ 7,622 $ (3,128) $ 4,494 $ 7,283 $ (2,441) $ 4,842 Intangible assets with finite lives are capitalized and amortized over their estimated economic lives. As of December 31, 2023, the remaining weighted-average amortization periods for finite-lived intangible assets were as follows: Weighted-Average Life (Years) Marketed products 8 Software 6 Other 6 The estimated amortization expense for each of the next five years associated with our finite-lived intangible assets, as of December 31, 2023, is as follows: 2024 2025 2026 2027 2028 Estimated amortization expense $ 552 $ 537 $ 529 $ 494 $ 491 For the years ended December 31, 2023, 2022 and 2021, amortization expense related to software was $54 million, $65 million and $52 million, respectively. As discussed in Note 2. Summary of Significant Accounting Policies, acquired IPR&D is not amortized, but rather is reviewed for impairment at least annually, or more frequently in the event of a triggering event. Acquired IPR&D assets are treated as indefinite-lived assets until completion or abandonment of the projects, at which time they are tested for impairment and, if not impaired, are transferred to marketed products and amortized over their estimated economic life. Amortization expense that will be incurred related to assets currently classified as acquired IPR&D upon their future transfer to marketed products, is not included in the future amortization expense table presented above, as we are not able to predict with certainty the period in which such related amortization will begin. Impairment charges related to acquired IPR&D included within asset impairment, restructuring and other special charges within our consolidated statements of operations for the years ended December 31, were as follows: 2023 2022 2021 Acquired IPR&D impairment $ 6 $ 59 $ 55

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment At December 31, property and equipment consisted of the following: 2023 2022 Land $ 40 $ 40 Buildings 630 578 Equipment 985 941 Construction in progress 186 163 1,841 1,722 Less accumulated depreciation (815) (723) Property and equipment, net $ 1,026 $ 999 Property and equipment, less accumulated depreciation, by geographic area as of December 31, was as follows: 2023 2022 United States $ 555 $ 554 Germany 245 224 France 59 52 Other foreign countries 167 169 Property and equipment, net $ 1,026 $ 999 Depreciation expense related to property and equipment for the years ended December 31, was as follows: 2023 2022 2021 Depreciation expense $ 92 $ 89 $ 108

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	Leases We have operating leases for corporate offices, research and development facilities, vehicles and equipment with lease terms generally ranging from one ROU assets represent our right to use an underlying asset for the lease term, while lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the lease commencement date based on the present value of lease payments over the lease term. As most of our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at lease commencement date in determining the present value of lease payments. We use the implicit rate if it is readily determinable. Our lease terms may include options to extend or terminate the lease, and when it is reasonably certain we will exercise that option, these extensions are included in the lease term used to calculate the ROU assets and operating lease liabilities. We do not include leases with a lease term of 12 months or less within the determination of our ROU assets or lease liabilities. Operating lease expense is recognized on a straight-line basis over the lease term. Variable lease payments, which represent lease payments that vary due to changes in facts or circumstances occurring after the commencement date, are expensed in the period in which the obligation for these payments is incurred. The impact of operating leases to the consolidated financial statements for the years ended December 31, was as follows: 2023 2022 2021 Lease cost Operating lease cost $ 42 $ 45 $ 43 Short-term lease cost 1 1 1 Variable lease cost 4 5 4 Total lease cost $ 47 $ 51 $ 48 Other information Operating cash outflows from operating leases $ 35 $ 33 $ 40 ROU assets obtained in exchange for new operating lease liabilities 28 32 36 Weighted-average remaining lease term - operating leases 7 years 7 years 7 years Weighted-average discount rate - operating leases 4.8 % 4.0 % 3.8 % Supplemental balance sheet information related to our operating leases is as follows: Asset/Liability Balance Sheet Classification December 31, 2023 December 31, 2022 Right-of-use assets Other noncurrent assets $ 140 $ 141 Current operating lease liabilities Other current liabilities 32 31 Non-current operating lease liabilities Other noncurrent liabilities 110 111 As of December 31, 2023, the annual minimum lease payments for our operating lease liabilities for the next five years and thereafter were as follows: 2024 $ 39 2025 30 2026 25 2027 16 2028 10 2029 and thereafter 44 Total lease payments 164 Less imputed interest (22) Total operating lease liabilities $ 142 Lease contracts that have been executed but have not yet commenced are excluded from the tables above. As of December 31, 2023, we have a lease commitment that has not yet commenced for our new corporate headquarters in Indianapolis, Indiana. Total minimum lease payments are estimated to be approximately $378 million over a term of 25 years, excluding extensions. Final lease payments may vary depending on the actual cost of certain construction activities. Lease commencement is expected in 2025.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation The Amended and Restated 2018 Elanco Stock Plan (Plan) provides long-term incentives to attract, motivate and retain employees and non-employee directors. The types of stock-based awards available include, but are not limited to, restricted stock units (RSUs), performance-based awards (PAs) and stock options. Our practices and policies specify that stock-based compensation awards are approved by the Compensation and Human Capital Committee of the Board of Directors (the Compensation Committee). In May 2023, our shareholders approved an increase in the total number of shares authorized for stock-based compensation by 20 million, raising the total number of shares authorized for stock-based compensation awards under the plan to 40 million. As of December 31, 2023, the aggregate number of remaining shares available for future grant was 26.6 million. Stock-Based Compensation Expense We measure compensation expense for stock-based awards based on grant date fair value and the estimated number of awards that are expected to vest. For purposes of measuring stock-based compensation expense, we consider whether an adjustment to the observable market price is necessary to reflect material nonpublic information that is known to us at the time the award is granted. Adjustments during the years ended December 31, 2023, 2022 and 2021, were not material. Forfeitures are estimated based on historical experience at the time of grant and are revised in subsequent periods if actual forfeitures differ from those estimates. Components of stock-based compensation expense and related tax benefit for the years ended December 31 were as follows: 2023 2022 2021 Total stock-based compensation expense (1) $ 46 $ 59 $ 66 (1) A majority of our stock-based compensation expense relates to RSUs and PAs. The associated tax benefit from stock-based compensation expense was offset by a valuation allowance. Restricted Stock Units RSUs are granted to certain employees and are settled in shares of our common stock. RSUs are accounted for at fair value based upon the closing stock price on the date of grant. The corresponding expense is amortized over the vesting period, which is typically three years. The number of shares ultimately issued for the RSU program remains constant with the exception of forfeitures. RSUs granted to employees for the years ended December 31 were as follows: (Units in millions) 2023 2022 2021 Granted units 3.2 1.3 1.1 Weighted-average grant date fair value $ 11.15 $ 28.17 $ 33.57 Changes in the nonvested portion of RSUs for 2023 are summarized below: (Shares in millions) Shares Weighted-Average Grant Date Fair Value Nonvested units at January 1, 2023 2.0 $ 29.40 Granted 3.2 11.15 Vested (1.0) 29.40 Forfeited (0.3) 23.22 Nonvested units at December 31, 2023 3.9 15.49 The fair market value of RSUs vesting in 2023, 2022 and 2021 was $12 million, $29 million and $30 million, respectively. As of December 31, 2023, the total remaining unrecognized stock-based compensation expense related to nonvested RSUs was $20 million, which is expected to be amortized over a weighted-average remaining requisite service period of 16 months. Performance-Based Awards PAs, which are granted to eligible officers and management, represent the right to receive a share of our common stock and are subject to forfeiture until restrictions lapse (including continued employment through the end of the vesting period and achievement of certain pre-established metrics). Payouts can vary depending on achievement. PAs are accounted for at fair value based upon the closing stock price on the date of grant and fully vest at the end of the measurement period. Stock-based compensation expense for PAs is recognized only if it is deemed probable that the performance condition will be achieved. PA activity during the year ended December 31, 2023, is summarized below: (Shares in millions) Shares Weighted-Average Grant Date Fair Value Nonvested awards at January 1, 2023 0.5 $ 28.94 Granted 1.6 11.25 Vested (0.7) 32.58 Forfeited (0.1) 15.64 Nonvested awards at December 31, 2023 1.3 11.25 The fair market value of PAs vesting in 2023, 2022 and 2021 was $8 million, $23 million and $22 million, respectively. As of December 31, 2023, the total remaining unrecognized stock-based compensation expense related to nonvested PAs was $9 million, which is expected to be amortized over a weighted-average remaining requisite service period of 12 months. Stock Options Stock options represent the right to purchase shares of our common stock within a specified period of time at a specified price. Stock options were granted in 2023 and 2022 to our officers and management at exercise prices equal to the fair market value of our stock at the date of the grant. Options fully vest three years from the grant date and have a term of 10 years. No stock options were granted in 2021. We account for our employee stock options under the fair value method of accounting using a Black-Scholes-Merton valuation model to measure stock option expense at the grant date, and the corresponding expense is generally amortized on a straight-line basis over the vesting term. The weighted-average fair value of stock options granted during the years ended December 31, 2023 and 2022 using the Black-Scholes-Merton valuation model was estimated to be $4.93 and $10.89, respectively. The Black-Scholes-Merton model incorporates a number of valuation assumptions, which are noted in the following table, shown at their weighted-average values for the years ended December 31: 2023 2022 Expected dividend yield (1) — % — % Risk-free interest rate (2) 4.08 % 1.59 % Expected stock price volatility (3) 38.2 % 36.5 % Expected term (4) (years) 6 6 (1) We have never declared nor paid any dividends on our common stock, and we do not anticipate paying dividends on our common stock for the foreseeable future. (2) Determined using the term-matched, zero-coupon risk-free rate from the Treasury Constant Maturity yield curve, continuously compounded. (3) Determined using a leverage-adjusted historical volatility of peer companies. (4) Determined using SEC safe harbor approach, based on a 3-year cliff vesting schedule and 10-year contractual term. Stock option activity during the year ended December 31, 2023, is summarized below: (Shares in millions) Shares of Common Stock Attributable to Options Weighted-Average Exercise Price of Options Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in millions) Outstanding at January 1, 2023 0.8 $ 30.11 Granted 1.1 11.26 Exercised — — Forfeited or expired (0.3) 18.40 Outstanding at December 31, 2023 1.6 $ 17.92 8.4 $ 4 Exercisable at December 31, 2023 0.3 30.86 6.2 —

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Our income tax provision for the years ended December 31, 2023, 2022 and 2021, includes income tax costs and benefits such as valuation allowances, uncertain tax positions, audit settlements and other items. We were included in Lilly's U.S. tax examinations by the Internal Revenue Service (IRS) through the full separation date of March 11, 2019. Pursuant to the tax matters agreement we executed with Lilly in connection with the IPO, the potential liabilities or potential refunds attributable to pre-IPO periods in which Elanco was included in a Lilly consolidated or combined tax return remain with Lilly. The U.S. examination by the IRS of tax years 2016 to 2018 began in 2019 and is ongoing. Final resolution of certain matters is dependent upon several factors, including the potential for formal administrative proceedings. Deferred taxes are recognized for the future tax effects of temporary differences between financial and income tax reporting based on enacted tax laws and rates. The tax benefit from an uncertain tax position is recognized only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate resolution. Deferred taxes are not provided on substantially all of the unremitted earnings of subsidiaries outside of the U.S., except where required, because it is expected that these earnings will be reinvested indefinitely. For the amount deemed indefinitely reinvested, it is not practicable to determine the amount of the related deferred income tax liability due to the complexities in the tax laws and assumptions required to be made. Deferred taxes, including U.S. or foreign withholding taxes, would be provided when we no longer consider our subsidiary earnings to be permanently invested, such as in situations where our subsidiaries plan to make future dividend distributions. We treat taxes due on future Global Intangible Low-Taxed Income (GILTI) inclusions in U.S. taxable income as a current period expense when incurred. Certain countries in which we have operations have adopted legislation influenced by the Organization for Economic Co-operation and Development (OECD) Pillar Two rules, including a minimum tax rate of 15%. It is uncertain whether the U.S. will enact legislation to adopt the Pillar Two framework. We are continuing to evaluate additional guidance released by the OECD, along with the pending legislative adoption by additional individual countries. The composition of loss before income tax expense (benefit) for the years ended December 31, was as follows: 2023 2022 2021 Federal $ (669) $ (350) $ (341) Foreign (526) 278 (230) Loss before income taxes $ (1,195) $ (72) $ (571) The composition of income tax expense (benefit) for the years ended December 31, was as follows: 2023 2022 2021 Current: Federal $ (8) $ 11 $ — Foreign 122 51 59 State 2 1 1 Total current tax expense 116 63 60 Deferred: Federal (3) (20) (11) Foreign (66) (36) (136) State (11) (1) (1) Total deferred tax benefit (80) (57) (148) Income tax expense (benefit) $ 36 $ 6 $ (88) Significant components of our deferred tax assets and liabilities as of December 31 were as follows: 2023 2022 Deferred tax assets: Compensation and benefits $ 37 $ 32 Accruals and reserves 55 54 Tax credit carryovers 57 53 Tax loss carryovers 314 329 Business interest deduction limitation 196 120 Inventories 24 30 Restructuring and other reserves 7 13 R&D capitalized assets 68 42 Operating lease liabilities 52 34 Deferred loss on derivatives designated as hedges 5 — Other assets — 13 Total gross deferred tax assets 815 720 Valuation allowances (363) (228) Total deferred tax assets 452 492 Deferred tax liabilities: Right-of-use assets (50) (34) Intangibles (837) (920) Property and equipment (74) (70) Deferred gain on derivatives designated as hedges — (42) Other liabilities (5) (6) Total deferred tax liabilities (966) (1,072) Deferred tax liabilities - net $ (514) $ (580) The deferred tax assets and related valuation allowance amounts for net operating losses and tax credits shown above have been adjusted for differences between financial reporting and tax return filings. At December 31, 2023, we had tax credit carryovers of $57 million available to reduce future income taxes. This amount was comprised of foreign, U.S. federal and state credits. The foreign credits totaled $8 million and if unused, will begin to expire in 2026. The U.S. federal credits totaled $33 million and if unused, will begin to expire in 2029. The state credits totaled $16 million and if unused, will begin to expire in 2027. The U.S. federal credits were subject to a partial valuation allowance and the state credits were subject to a full valuation allowance. At December 31, 2023, we had net operating loss carryovers for foreign, U.S. federal and state income tax purposes of $314 million. Of this total, $120 million will expire between 2024 and 2036, and $195 million of the carryovers had an indefinite carryforward period. Net operating losses and other carryovers for foreign, U.S. federal and state income tax purposes were subject to full and partial valuation allowances. Movements in the valuation allowance for the years ended December 31, are summarized as follows: 2023 2022 January 1 $ (228) $ (182) Increase (141) (49) Release 6 3 December 31 $ (363) $ (228) The increase in the valuation allowance during 2023 was primarily attributable to the likelihood of not realizing the benefit of U.S. federal and state deferred tax assets because of U.S. pre-tax losses. The total net increase in the valuation allowance recorded in income tax expense (benefit) in the consolidated statements of operations was $93 million, $80 million and $76 million in 2023, 2022 and 2021, respectively, with the remaining change in balance primarily recorded through accumulated other comprehensive loss. Cash payments of income taxes during the years ended December 31, were as follows: 2023 2022 2021 Cash payments of income taxes $ 95 $ 93 $ 151 Income taxes receivable of $149 million and $180 million, respectively, were included in prepaid expenses and other on our consolidated balance sheets as of December 31 2023 and 2022. The following is a reconciliation of the income tax expense (benefit) applying the U.S. federal statutory rate to income before income taxes to reported income tax expense: 2023 2022 2021 Income tax benefit at the U.S. federal statutory tax rate $ (251) $ (15) $ (120) Add (deduct): Taxation of international operations 3 (43) (16) State taxes (12) (11) (8) Income tax credits (10) (13) (14) Non-deductible employee compensation 15 7 4 Goodwill and other asset impairments 164 — — Other permanent adjustments 19 (2) (8) Change in uncertain tax positions 15 3 (2) Change in valuation allowance 93 80 76 Income tax expense (benefit) $ 36 $ 6 $ (88) Goodwill impairment (see Note 11. Goodwill and Intangibles for further information) was not deductible for income tax purposes in most of the impacted jurisdictions. Taxation of international operations for the year ended December 31, 2022, included a $16 million benefit related to an income tax refund claim in Brazil resulting from a Brazil Supreme Court decision that determined certain Brazil state value-added tax (VAT) incentives were not subject to federal tax. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for the years ended December 31, was as follows: 2023 2022 2021 Beginning balance at January 1 $ 16 $ 6 $ 3 Additions based on tax positions related to the current year 2 3 — Changes for tax positions of prior years 13 — (1) Additions related to acquisitions — 7 4 Ending balance at December 31 $ 31 $ 16 $ 6 The total amount of unrecognized tax benefits that, if recognized, would affect tax expense was $31 million and $16 million at December 31, 2023 and 2022, respectively. We recognize both accrued interest and penalties related to unrecognized tax benefits in income tax expense (benefit). Interest and penalties related to income tax matters were not material for the years ended December 31, 2023, 2022 and 2021.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Matters We are party to various legal actions that arise in the normal course of business. The most significant matters are described below. Under GAAP, loss contingency provisions are recorded when we deem it probable that we will incur a loss and we are able to formulate a reasonable estimate of that loss. Seresto Class Action Lawsuits and EPA Safety Review Claims seeking actual damages, injunctive relief and/or restitution for allegedly deceptive marketing have been made against Elanco Animal Health Inc. and Bayer HealthCare LLC, along with other Elanco and Bayer entities, arising out of the use of Seresto™ , a non-prescription flea and tick collar for cats and dogs. During 2021, putative class action lawsuits were filed in federal courts in the U.S. alleging that the Seresto collars contain pesticides that can cause serious injury and death to cats and/or dogs wearing the product. In August 2021, the lawsuits were consolidated by the Judicial Panel on Multidistrict Litigation, and the cases were transferred to the Northern District of Illinois. In June 2023, the parties agreed on the monetary terms of a potential settlement of the consolidated class action lawsuits, and as a result, a charge of $15 million was recorded. As of December 31, 2023, the parties had agreed on the non-monetary terms of a potential settlement, in addition to the monetary terms agreed to in June 2023. In January 2024, the court preliminarily approved the settlement. The court set a hearing to consider final approval of the settlement in December 2024. If at that time all conditions of the settlement are met, and the settlement is approved, we anticipate the settlement amount will be payable in the the first or second quarter of 2025. As such, the $15 million provision was included within other noncurrent liabilities on our consolidated balance sheet as of December 31, 2023. Also, in January 2023, a lawsuit seeking damages for alleged negligence, breach of statutory regulations, breach of statutory duties and deceptive marketing was filed in Israel against Elanco and other parties, arising out of the use of Seresto and Foresto™ flea and tick collars for cats and dogs that are marketed and sold in Europe and in Israel. We intend to defend our position vigorously, and as of the date of this filing, we are unable to estimate the probability of loss or range of loss, if any. Seresto is a pesticide registered with the U.S. Environmental Protection Agency (EPA). In April 2021, a non-profit organization submitted a petition to the EPA requesting that the agency take action to cancel Seresto’s pesticide registration and suspend the registration pending cancellation. In response to the EPA's request for comments from the public on the petition, we submitted a comment to the EPA supporting the safety profile of Seresto and engaged in discussions with the EPA. On July 13, 2023, the EPA announced their completion of a comprehensive, multi-year review, with support from the FDA, of the Seresto flea and tick collar and confirmed the continued registration of the collar, denying the citizen's petition. As part of the EPA’s scientific review process, the agency analyzed incident data including third-party assessments and compared data to other EPA registered pet products. Based on comprehensive data from the review, the EPA concluded that Seresto continues to meet all the EPA’s standards for registration under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), which ensures that products do not pose unreasonable risk of harm. Additional Legal Matters For the litigation matters discussed below we either believe loss is not probable or are unable to estimate the possible loss or range of loss, if any. The process of resolving these matters is inherently uncertain and may develop over an extended period of time; therefore, at this time, the ultimate resolutions cannot be predicted. As of December 31, 2023 and 2022, we had no material liabilities established related to the litigation matters discussed below. On May 20, 2020, a shareholder class action lawsuit captioned Hunter v. Elanco Animal Health Inc., et al. was filed in the United States District Court for the Southern District of Indiana (Court) against Elanco and certain executives. On September 3, 2020, the Court appointed a lead plaintiff, and on November 9, 2020, the lead plaintiff filed an amended complaint adding additional claims against Elanco, certain executives and other individuals. The lawsuit alleged, in part, that Elanco and certain of its executives made materially false and/or misleading statements and/or failed to disclose certain facts about Elanco’s supply chain, inventory, revenue and projections. The lawsuit sought unspecified monetary damages and purports to represent purchasers of Elanco securities between September 30, 2018 and May 6, 2020, and purchasers of Elanco common stock issued in connection with Elanco's acquisition of Aratana. On January 13, 2021, we filed a motion to dismiss, and on August 17, 2022, the Court issued an order granting our motion to dismiss the case without prejudice. On October 14, 2022, the plaintiffs filed a motion for leave to amend the complaint. On December 7, 2022, we filed an opposition to the plaintiffs' motion, and on September 27, 2023, the Court denied the plaintiffs' motion for leave, issuing final judgment in favor of Elanco. On October 25, 2023, the plaintiffs filed a notice of appeal to the United States Court of Appeals for the Seventh Circuit. We continue to believe the claims made in the case are meritless, and we intend to continue to vigorously defend our position. On October 16, 2020, a shareholder class action lawsuit captioned Saffron Capital Corporation v. Elanco Animal Health Inc., et al. was filed in the Marion Superior Court of Indiana against Elanco, certain executives and other individuals and entities. On December 23, 2020, the plaintiffs filed an amended complaint adding an additional plaintiff. The lawsuit alleges, in part, that Elanco and certain of its executives made materially false and/or misleading statements and/or failed to disclose certain facts about Elanco’s relationships with third party distributors and revenue attributable to those distributors within the registration statement on Form S-3 dated January 21, 2020 and accompanying prospectus filed in connection with Elanco’s public offering which closed on or about January 27, 2020. The lawsuit seeks unspecified monetary damages and purports to represent purchasers of Elanco common stock or TEUs issued in connection with the public offering. From February 2021 to August 2022, this case was stayed in deference to Hunter v. Elanco Animal Health Inc . On October 24, 2022, we filed a motion to dismiss. On December 23, 2022, the plaintiffs filed their opposition to the motion to dismiss. Prior to the ruling on the motion to dismiss, on June 8, 2023, the plaintiffs filed a motion for leave to file a second amended complaint, which is now the operative complaint. We filed a motion to dismiss the complaint on August 7, 2023, to which the plaintiff filed their opposition on October 13, 2023. We continue to believe the claims made in the case are meritless, and we intend to vigorously defend our position. In the third quarter of 2019, Tevra Brands, LLC (Tevra) filed a complaint in the U.S. District Court of the Northern District of California, alleging that Bayer Animal Health (acquired by us in August 2020) had been involved in unlawful, exclusive dealing and tying of its flea and tick products Advantage , Advantix and Seresto and maintained a monopoly in the market. The complaint was amended in March 2020 and then dismissed in September 2020 with leave to amend. A second amended complaint was filed in March 2021 and realleges claims of unlawful exclusive dealing related to Advantage and Advantix and monopoly maintenance. A motion to dismiss the second amended complaint was denied in January 2022. Tevra’s demands include both actual and treble damages. The trial is scheduled for July 2024. We intend to defend our position vigorously. Regulatory Matters On July 1, 2021, we received a subpoena from the SEC relating to our channel inventory and sales practices prior to mid-2020. We have cooperated in providing documents and information to the SEC and will continue to do so. We have engaged in discussions with the SEC about a possible resolution or settlement of potential disclosure claims. While we have not reached an agreement on a resolution or settlement of the potential disclosure claims, based on the ongoing discussions with the SEC, we believe a loss contingency is both probable and estimable. Accordingly, we have accrued a liability of $12.5 million as of December 31, 2023, which was reflected within other expense, net, in the consolidated statements of operations and within other current liabilities in the consolidated balance sheets. It remains uncertain whether an agreement will be reached and the terms of any such agreement. Management continues to believe its actions were appropriate. Other Commitments As of December 31, 2023, we had a lease commitment that has not yet commenced for our new corporate headquarters in Indianapolis, Indiana. See Note 13. Leases for further information regarding this lease commitment. The land for our new corporate headquarters is located in a Tax Increment Finance District, and the project is, in part, funded through Tax Incremental Financing (TIF) through an incentive agreement between us and the City of Indianapolis. The agreement provides for an estimated total incentive of $64 million to be funded by the City of Indianapolis in connection with the future tax increment revenue generated from the developed property. In December 2021, as part of a funding and development agreement entered into between us and the developer, we made a commitment to use the expected TIF proceeds towards the cost of developing and constructing the headquarters. In exchange, the developer reimbursed us up to the $64 million commitment in 2021. During 2022, we refunded approximately $15 million of the TIF proceeds to the developer. As a result, it is our expectation that our future lease payments will be reduced. The remaining accrued incentive was included in other noncurrent liabilities on our consolidated balance sheets and will be amortized over the lease term beginning on the commencement date and offset future rent expense.

Retirement Benefits

Retirement Benefits	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Retirement Benefits	Retirement Benefits Pension Plans We sponsor various defined benefit pension plans, which cover certain employees worldwide. Our plans in Switzerland and Germany represent approximately 92% of our global benefit obligation. We use a measurement date of December 31 to develop the change in benefit obligation, change in plan assets, funded status and amounts recorded on the consolidated balance sheets at December 31 for our defined benefit pension plans, which were as follows: Change in benefit obligation: 2023 2022 Benefit obligation at beginning of year $ 324 $ 462 Service cost 9 14 Interest cost 11 4 Actuarial loss (gain) 17 (123) Benefits paid (14) (12) Foreign currency exchange rate changes and other adjustments 19 (21) Benefit obligation at end of year 366 324 Change in plan assets: Fair value of plan assets at beginning of year 175 207 Actual return on plan assets 8 (26) Employer contribution 11 12 Benefits paid (14) (12) Foreign currency exchange rate changes and other adjustments 12 (6) Fair value of plan assets at end of year 192 175 Funded status (174) (148) Unrecognized net actuarial gain (63) (82) Unrecognized prior service cost (28) (30) Net amount recognized $ (265) $ (260) Amounts recognized in the consolidated balance sheet as of December 31, consisted of: Other noncurrent assets $ 1 $ 2 Other current liabilities (1) — Accrued retirement benefits (174) (150) Accumulated other comprehensive loss before income taxes (91) (112) Net amount recognized $ (265) $ (260) The unrecognized net actuarial gain and unrecognized prior service cost for these pension plans have not yet been recognized in net periodic pension expense and were included in accumulated other comprehensive loss at December 31, 2023. We do not expect any plan assets to be returned to us in 2024. The following represents our weighted-average assumptions related to these pension plans as of and for the years ended December 31: (Percentages) 2023 2022 2021 Discount rate for benefit obligation 2.8 % 3.4 % 1.1 % Discount rate for net benefit costs 3.4 1.1 0.6 Rate of compensation increase for benefit obligation 2.9 3.0 2.7 Rate of compensation increase for net benefit costs 3.0 2.7 3.1 Expected return on plan assets for net benefit costs 4.4 3.1 2.9 The assumptions above were used both to estimate our pension benefit obligations at year-end, as well as in the determination of applicable pension benefit costs for the years presented. These assumptions are reviewed on at least an annual basis and are revised based on a yearly evaluation of long-term trends and market conditions that may impact the cost of providing retirement benefits. The weighted-average discount rates for our defined benefit plans are set by benchmarking against investment grade corporate bonds where available, including, when there is sufficient data, a yield curve approach. For countries that lack a sufficient corporate bond market, a government bond index is used to establish the discount rate. In evaluating the expected rate of return, we consider many factors, with a primary analysis of current and projected market conditions, asset returns and asset allocations and the views of leading financial advisers and economists. We may also review our historical assumptions compared with actual results, as well as the assumptions and trend rates utilized by similar plans, where applicable. Future benefit payments as of December 31, 2023, which reflect expected future service, as appropriate, are expected to be as follows: 2024 2025 2026 2027 2028 2029-2033 Benefit payments $ 14 $ 15 $ 15 $ 16 $ 16 $ 93 We also expect to contribute $10 million to our pension plans in 2024. Amounts relating to pension plans with projected benefit obligations in excess of plan assets were as follows at December 31: 2023 2022 Projected benefit obligation $ 343 $ 301 Fair value of plan assets 168 150 Amounts relating to defined benefit pension plans with accumulated benefit obligations in excess of plan assets were as follows at December 31: 2023 2022 Accumulated benefit obligation $ 332 $ 289 Fair value of plan assets 168 146 The total accumulated benefit obligation for our defined benefit pension plans was $354 million and $314 million at December 31, 2023 and 2022, respectively. Net pension expense (benefit) related to our defined benefit pension plans for the years ended December 31, included the following components: 2023 2022 2021 Service cost $ 9 $ 14 $ 18 Interest cost 11 4 2 Expected return on plan assets (8) (6) (6) Amortization of prior service cost (5) (5) (6) Amortization of net actuarial (gain) loss (3) 1 2 Net curtailments and settlements — — (29) Net pension expense (benefit) $ 4 $ 8 $ (19) The components of net periodic benefit expense, other than service cost and net curtailments and settlements, were included in other expense, net in the consolidated statements of operations. Net curtailments and settlements related to the remeasurement of our pension benefit obligation as a result of workforce reductions in connection with past restructuring programs. See Note 5. Asset Impairment, Restructuring and Other Special Charges for further information. The following represents the pre-tax amounts recognized for defined benefit plans in other comprehensive income (loss) for the years ended December 31, 2023: 2023 2022 2021 Actuarial (loss) gain arising during period $ (17) $ 92 $ 29 Amortization of prior service cost, including settlements, in net loss (5) (5) (36) Amortization of net actuarial (gain) loss, including curtailments, in net loss (3) 1 22 Foreign currency exchange rate changes and other 5 2 — Total other comprehensive (loss) income during period $ (20) $ 90 $ 15 We recognized $3 million and $11 million of income tax expense in other comprehensive income (loss), respectively, related to our defined benefit plans during the years ended December 31, 2023 and 2022. Amounts recognized in 2021 were not material. Benefit Plan Investments Our benefit plan investment policies are set with specific consideration of return and risk requirements in relationship to the respective liabilities. Our plan assets related to our pension plans in Switzerland and Germany represent approximately 87% of our total plan assets for all pension plans. Given the long-term nature of our liabilities, our plans have the flexibility to manage an above-average degree of risk in the asset portfolios. At the investment-policy level, there are no specifically prohibited investments; however, individual investment manager mandates, restrictions and limitations are contractually set to align with our investment objectives, ensure risk control and limit concentrations. We manage our portfolio to minimize concentration of risk by allocating funds within asset categories. In addition, within a category we use different managers with various management objectives to eliminate any significant concentration of risk. The investment strategy for the legacy Elanco plans is to diversify our plan assets with a designated percentage invested in fixed-income securities, equity securities, real estate and other alternative investments. The acquired Bayer Animal Health plans are managed separately, and underlying investments are classified in the same categories. Each category is diversified and comprised of the following: • Fixed-income securities – Swiss bonds, global aggregates, global aggregate corporates, global government bonds, emerging market local currencies and emerging markets hard currencies. • Equity securities – Swiss equities, global equities, low volatility equities (to reduce risk) and emerging market equities. • Real estate – Swiss real estate and global real estate funds. • Other alternative investments – cash, cash equivalents and investments in senior secured loans. We determine the fair value of the investments based on a market approach using quoted market values, significant other observable inputs for identical or comparable assets or liabilities. Real estate is mostly comprised of public holdings. Real estate investments in registered investment companies that trade on an exchange are classified as Level 1 on the fair value hierarchy. Other real estate investments are marked to fair value using models that are supported by observable market-based data (Level 2). The fair values of pension plan assets as of December 31, 2023, by asset category were as follows: Fair Value Measurements Using Asset Class Total Quoted Prices in Active Markets for Identical Assets Significant Observable Significant Unobservable Inputs Investments Valued at NAV (1) Public equity securities $ 58 $ 55 $ — $ — $ 3 Fixed income: Developed markets 72 71 — — 1 Emerging markets 12 12 — — — Real estate 18 11 7 — — Other 32 28 4 — — Total $ 192 $ 177 $ 11 $ — $ 4 (1) Certain investments measured at fair value using the Net Asset Value (NAV) per share, or its equivalent, as a practical expedient have not been classified in the fair value hierarchy. No material transfers between Level 1, Level 2, or Level 3 occurred during the year ended December 31, 2023. The fair values of pension plan assets as of December 31, 2022, by asset category were as follows: Fair Value Measurements Using Asset Class Total Quoted Prices in Active Markets for Identical Assets Significant Observable Significant Unobservable Inputs Investments Valued at NAV (1) Public equity securities $ 49 $ 47 $ — $ — $ 2 Fixed income: Developed markets 64 63 — — 1 Emerging markets 9 9 — — — Real estate 23 17 6 — — Other 30 25 5 — — Total $ 175 $ 161 $ 11 $ — $ 3 (1) Certain investments measured at fair value using NAV per share, or its equivalent, as a practical expedient have not been classified in the fair value hierarchy. No material transfers between Level 1, Level 2, or Level 3 occurred during the year ended December 31, 2022. Defined Contribution Plans Elanco has defined contribution savings plans that include certain employees worldwide. Our contributions to these plans are based on our employee contributions and the level of our match. Expenses under the plans totaled $40 million, $34 million and $39 million for the years ended December 31, 2023, 2022 and 2021, respectively. Multiemployer Plans Through the acquisition of Bayer Animal Health, we acquired participation in certain multiemployer arrangements with Bayer-Pensionskasse VVaG, Leverkusen (Germany) (Bayer-Pensionskasse) and Rheinishche Pensionskasse VVaG, Leverkusen (Germany) (Rheinishche Pensionskasse). These plans provide basic pension benefits to the majority of our employees in Germany. Up to a certain salary level, the benefit obligations are covered by our contributions and the contributions from employees to the plan. The Company-specific plan information for Bayer-Pensionskasse and Rheinische-Pensionskasse is not publicly available, and the plans are not subject to a collective-bargaining agreement. The plans provide fixed, monthly retirement payments on the basis of the credits earned by the participating employees. To the extent Bayer-Pensionskasse or Rheinische-Pensionskasse are underfunded, our future contributions to the plan(s) may increase and may be used to fund retirement benefits for employees related to other employers, although as of December 31, 2022 and 2021, both plans' total assets exceeded the total actuarial present value of accumulated plan benefits. Our plan contributions to these plans are expensed as incurred and were not material in any of the years ended December 31, 2023, 2022 and 2021, nor did they exceed 5% of the total contributions to the plans.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share We compute basic earnings (loss) per share by dividing net income (loss) available to common shareholders by the actual weighted-average number of common shares outstanding for the reporting period. Elanco has variable common stock equivalents relating to certain equity awards in stock-based compensation arrangements. We also had variable common stock equivalents related to the TEU prepaid stock purchase contracts through their settlement date of February 1, 2023 (see Note 7. Equity for further discussion). Diluted earnings per share reflects the potential dilution that could occur if holders of the unvested equity awards converted their holdings into common stock and that could have occurred if holders of unsettled TEUs had converted their holdings into common stock prior to the February 1, 2023, settlement date. The weighted-average number of potentially dilutive shares outstanding was calculated using the treasury stock method. Potential common shares that would have had the effect of increasing diluted earnings per share (or reducing loss per share) were considered to be anti-dilutive and as such, these shares were not included in the calculation of diluted loss per share. Basic and diluted weighted-average shares outstanding were as follows: 2023 2022 2021 Determination of shares: Weighted-average common shares outstanding (1) 492.3 488.3 487.2 Assumed conversion of dilutive common stock equivalents (2) — — — Diluted weighted-average shares outstanding 492.3 488.3 487.2 (1) The TEU prepaid stock purchase contracts were convertible into a minimum of 14.3 million shares or a maximum of 17.2 million shares. The minimum 14.3 million shares were included in the calculation of basic weighted-average shares from January 22, 2020 to February 1, 2023. The 17.2 million shares that were ultimately issued were included in the calculation of basic weighted-average shares subsequent to the settlement date of February 1, 2023. (2) For the years ended December 31, 2023, 2022 and 2021, approximat ely 2.9 million,

Related Party Agreements and Tr

Related Party Agreements and Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Party Agreements and Transactions	Related Party Agreements and Transactions During the second quarter of 2023, Ellen de Brabander, Executive Vice President, Innovation and Regulatory Affairs, joined the Board of Directors of Archer Daniels Midland Company (ADM), serving on ADM's audit committee and sustainability and corporate responsibility committee. In her capacity with Elanco, Ellen oversees our global research and development organization and regulatory affairs. ADM is a global human and animal nutrition company, and throughout the normal course of business, we purchase various raw materials from ADM for use in the manufacturing of certain of our products. Total purchases from ADM since Ms. de Brabander joined its Board of Directors were not material.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2023
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Announced sale of aqua business: In February 2024, we entered into an asset purchase agreement (the agreement) to sell our aqua business to Intervet International B.V., a Dutch subsidiary of Merck Animal Health for approximately $1.3 billion in cash, payable at closing. This divestiture is expected to include inventories, real property and equipment, including our manufacturing sites in Canada and Vietnam, and certain intellectual property, technology and other intangible assets, including marketed brands, as well as approximately 280 commercial and manufacturing employees. The agreement contains certain representations, warranties and covenants that are customary for transactions of this nature, including covenants by us relating to the operation of the aqua business prior to the closing of the agreement, as well as certain non-compete restrictions. The closing of the agreement is subject to customary closing conditions, including the receipt of applicable regulatory and antitrust approvals, and is currently anticipated to occur around mid-year 2024. If the agreement is terminated due to failure to obtain the applicable required approvals, subject to certain conditions, Merck Animal Health will be required to pay us a termination fee of $55 million in cash. Our aqua business includes products across both warm-water and cold-water species and generated $175 million in revenue during the year ended December 31, 2023. The aqua business assets being sold met the criteria to be classified as held for sale in February 2024, when all the required criteria for held for sale classification, as outlined within GAAP, were met. We have determined that this future divestiture does not qualify for reporting as a discontinued operation, as it does not represent a strategic shift that has or will have a major effect on our operations and/or financial results. Approved restructuring plan: In February 2024 our Board of Directors authorized a restructuring plan (the restructuring plan) to improve operational efficiencies and better align our organizational structure with current business needs, top strategic priorities and key growth opportunities. Specifically, the restructuring plan is intended to reallocate resources by shifting international resources from farm animal to pet health as we plan for the global launches of certain potential blockbuster products currently under regulatory review. Further, the restructuring plan is expected to result in changes in how we operate in and sell into the Argentina market, among others, which we anticipate will reduce our foreign currency exposure. The restructuring plan will result in the elimination of approximately 420 personnel across our global organization. Expected pre-tax charges associated with the restructuring plan total $50 to $55 million in 2024, including $40 to $45 million of cash-based severance costs, the majority of which will be paid in 2024.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (1,231)	$ (78)	$ (483)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	We have prepared the accompanying consolidated financial statements in accordance with accounting principles generally accepted in the United States (GAAP). In our opinion, the financial statements reflect all adjustments (including those that are normal and recurring) that are necessary for fair presentation of the results of operations for the periods shown. All intercompany balances and transactions have been eliminated. In preparing financial statements in conformity with GAAP, we must make estimates and assumptions that affect the reported amounts of assets, liabilities, revenue, expenses and related disclosures at the date of the financial statements and during the reporting period. Actual results could differ from those estimates. We issued our financial statements by filing with the Securities and Exchange Commission (the SEC) and have evaluated subsequent events up to the time of filing. Certain reclassifications of prior year information have been made to conform to the current year's presentation.
Estimates and Assumptions	The preparation of financial statements in accordance with GAAP requires us to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses. These estimates and underlying assumptions can impact all elements of our consolidated financial statements. Our estimates are often based on several factors, including the facts and circumstances available at the time the estimates are made, historical experience, risk of loss, general economic conditions and trends and the assessment of the probable future outcome. Some of our estimates require significant, difficult or complex judgments, probabilities and assumptions that we believe to be reasonable but that can be inherently uncertain and unpredictable. If our estimates and assumptions are not representative of actual outcomes, our results could be materially impacted. We regularly evaluate our estimates and assumptions and adjust them when facts and circumstances indicate the need for change. Such changes generally would be reflected in our consolidated financial statements in the period they are determined. We apply estimation methodologies consistently from year to year.
Revenue	We recognize revenue primarily from product sales to customers. Revenue from sales of products is recognized at the point where the customer obtains control of the goods and we satisfy our performance obligation, which is generally once the goods have shipped and the customer has assumed title. For contract manufacturing organization (CMO) arrangements, we recognize revenue over time or at a point in time depending on our evaluation of when the customer obtains control of the promised goods or service. Revenue reflects the total consideration to which we expect to be entitled (i.e., the transaction price), in exchange for products sold, after considering various types of variable consideration, such as rebates, sales allowances, product returns and discounts. Provisions for rebates and discounts, as well as returns, are established in the same period the related sales are recognized. Significant judgments must be made in determining the transaction price for sales of products related to anticipated rebates, discounts and returns. The following describe the most significant of these judgments: Sales Rebates and Discounts • Many of our products are sold and initially invoiced at contractual list prices. Contracts with customers often provide for various rebates and discounts that may differ in each contract. As a consequence, to determine the appropriate transaction price for our product sales, we must estimate any rebates or discounts that ultimately will be due to the customer under the terms of our contracts. The rebate and discount amounts are recorded as a deduction to revenue to arrive at our net product sales during the period in which revenue is recognized. Significant judgment is involved in determining the rebate and discount amounts expected to be payable to a customer. In determining the appropriate accrual amount, we consider our historical experience with similar incentives programs and current sales data and estimates of inventory levels at our channel distributors to evaluate the impact of such programs on revenue. We continually monitor the impact of this experience and adjust our accrual amounts as necessary. Although we accrue a liability for rebates related to these programs at the time the sale is recorded, the rebate related to that sale is typically paid up to six months after the rebate or incentive period expires. Because of this, in any particular period rebate adjustments may incorporate revisions of accruals for several periods. Sales Returns • We estimate a reserve for future product returns based on several factors, including local returns policies and practices, historical returns as a percentage of revenue, an understanding of the reasons for past returns, estimated shelf life by product and estimates of the amount of time between shipment and return. Reserves for sales returns are estimated and recorded in the same period as the underlying revenue recognition as a deduction to arrive at our net product sales and as a liability. Payment terms differ by jurisdiction and customer, but typically range from 30 to 120 days from date of shipment in most of our major jurisdictions. Revenue for our product sales has not been adjusted for the effects of a financing component, as we expect the period between when we transfer control of the product and when we receive payment will be one year or less. Any exceptions are either not material or we collect interest for payments made after the due date. Shipping and handling activities are considered fulfillment activities and are not considered to be a separate performance obligation. We exclude from the measurement of the transaction price all taxes assessed by a governmental authority that are imposed on our sales of product and collected from a customer.
Allowance for Doubtful Accounts	We provide for an allowance for doubtful accounts, which represents our best estimate of expected lifetime credit losses inherent in our accounts and other receivables portfolios. Our estimates include a continuing credit evaluation of customers' financial condition, trade accounts and other receivables aging and historical loss experience, as well as reasonable and supportable forecasts of future economic conditions.
Inventories	Effective October 1, 2023, we changed our method of accounting for portions of our inventories from the weighted-average cost method to the first-in-first-out (FIFO) method. As of December 31, 2022, inventories accounted for using the weighted-average cost method were approximately 30% of total inventories. We believe the FIFO method is preferable because it is expected to more accurately match revenue with expenses and reflects the current value of inventories on the consolidated balance sheets. Additionally, it will conform the inventory valuation methodology used for the majority of our inventories and improve comparability with industry peers.
Research and Development Expenses	Research and development (R&D) costs are expensed as incurred and relate to the effort associated with the discovery of new knowledge that will be useful in developing a new product or in significantly improving an existing product and the implementation of the research findings. R&D costs include, but are not limited to, compensation and benefits, facilities and overhead expense, clinical trial expense and fees paid to contract research organizations. We may also enter into licensing arrangements with third parties to acquire the rights to in-process research and development (IPR&D). These arrangements typically do not meet the definition of a business combination. In such
Goodwill and Indefinite-lived Intangible Assets	Goodwill represents the excess of the consideration transferred for an acquired business over the assigned fair value of the net assets acquired. Goodwill is not amortized, but is reviewed at least annually for impairment during the fourth quarter, or more frequently if there is a significant change in events or circumstances that indicate the fair value of our single reporting unit is more likely than not less than its carrying amount (i.e., a triggering event). When required, a comparison of fair value to the carrying amount of our single reporting unit is performed to determine the amount of impairment, if any. We begin by assessing qualitative factors to determine whether it is more likely than not that the fair value of our single reporting unit is less than its carrying value. Based on that qualitative assessment, if we conclude it is more likely than not that the fair value of our single reporting unit is less than its carrying value, we conduct a quantitative goodwill impairment test, which involves comparing the estimated fair value of our single reporting unit to its carrying value, including goodwill. We estimate the fair value of our single reporting unit using an income approach, which is a valuation technique that provides an estimate of the fair value of an asset based on market participant expectations of the cash flows an asset would generate over its remaining useful life. If the carrying value of the reporting unit exceeds its estimated fair value, we recognize an impairment loss for the difference. During the third quarter of 2023, there was a sharp increase in long-term treasury rates, and as a result we assessed our long-lived assets for impairment, concluding that a triggering event existed as of September 30, 2023, for certain indefinite-lived assets, including goodwill. Accordingly, we performed an interim quantitative goodwill impairment test, which resulted in a $1,042 million pre-tax impairment charge. The fair value of our single reporting unit was determined using the income approach, based on a discounted cash flow model. Significant management judgment was required in estimating our reporting unit’s fair value, including, but not limited to, estimates and assumptions regarding future cash flows, revenue growth and other profitability measures such as gross margin and EBITDA margin, and the determination of an appropriate discount rate. We made these judgments based on historical experience, relevant market size, historical pricing and expected industry trends. See Note 11. Goodwill and Intangibles for further information. Similar to goodwill, indefinite-lived intangible assets, which primarily represent IPR&D acquired from prior business combinations and to a lesser extent, acquired trade names, are not amortized, but rather are reviewed annually for impairment during the fourth quarter, or more frequently in the event of a triggering event. We utilize the income method for determining the estimated fair value of indefinite-lived intangible assets upon acquiring them in a business combination and as needed for our evaluations of potential impairment. This method is a Level 3 fair value measurement in the fair value hierarchy (see Note 10. Fair Value for further information) and applies a probability weighting that considers the risk of development and commercialization to the estimated future net cash flows derived from projected revenues and estimated costs. These projections are based on factors such as relevant market size, patent protection, historical pricing of similar products and expected industry trends. The estimated future net cash flows are then discounted to the present value using an appropriate discount rate. Acquired IPR&D assets are treated as indefinite-lived intangible assets until completion or abandonment of the projects, at which time the assets are tested for impairment and, if not impaired, are transferred to marketed products (see below) and amortized over their estimated economic life.
Property and equipment	Property and equipment: • Property and equipment assets are stated at cost less accumulated depreciation. Assets placed in service are recorded at cost and depreciated using the straight-line method over the estimated useful life of the asset (12 to 50 years for buildings and 3 to 25 years for equipment), except for leasehold improvements, which are depreciated over the shorter of their economic useful life, or their remaining lease term. Repair and maintenance costs that do not extend the useful life of the asset are expensed as incurred. Major replacements and significant improvements that either increase asset values or extend useful lives are capitalized. We assess the recoverability of the carrying value of the property and equipment asset or asset group that includes the property and equipment whenever events or changes in circumstances indicate the carrying amount of the asset may not be fully recoverable. When such indications of a potential impairment exist, we compare the projected undiscounted cash flows to be generated by the asset (or asset group) to its carrying value. If the carrying amount is found to be greater, an impairment charge is recorded equal to the excess of the asset's carrying value over its fair value. In such an event, we also re-evaluate the remaining useful lives of the assets (or asset group) and modify them, as appropriate.
Finite-lived intangible assets	Finite-lived intangible assets: • Finite-lived intangible assets primarily relate to marketed products acquired or licensed from third parties and software. Marketed products consist of the amortized cost of the rights to assets acquired in business combinations and approved for marketing in a significant global jurisdiction. The cost basis of marketed products includes both the initial assigned IPR&D value, as well as any associated milestone payments subsequent to the marketed products receiving regulatory approval in a significant global jurisdiction. Software consists of certain costs incurred in connection with obtaining or developing internal-use software, including payroll and payroll-related costs for employees directly associated with the internal-use software projects and direct costs of external resources. Other finite-lived intangible assets consist primarily of the amortized cost of licensed platform technologies, manufacturing technologies and customer relationships. Intangible assets with finite lives are capitalized and amortized over their estimated economic lives, typically ranging from 3 to 20 years. We assess the recoverability of the carrying value of finite-lived intangible assets in the same manner as property and equipment, as described above.
Advertising Expenses	Costs associated with advertising, including costs for TV, radio and other electronic media and publications, are generally expensed when the related advertising occurs, and are included in marketing, selling and administrative expenses in the consolidated statements of operations. Advertising and promotion expenses for the years ended December 31, 2023, 2022 and 2021, approximated $207 million, $201 million and $248 million, respectively.
Foreign Currency Translation	Operations in our subsidiaries outside the U.S. are recorded in the functional currency of each subsidiary, which is determined by a review of the environment where each subsidiary primarily generates and expends cash. The results of operations for our subsidiaries outside the U.S., where the U.S. dollar is not the functional currency, are translated from functional currencies into U.S. dollars using the weighted-average currency rate for the period. Assets and liabilities are translated using the period-end exchange rates. The U.S. dollar effects that arise from translating the net assets of these subsidiaries are recorded in other comprehensive income (loss). Foreign currency transaction gains and losses are due to the effect of exchange rate changes on transactions denominated in currencies other than a subsidiary's functional currency and are recognized in other income (expense), net, in the consolidated statements of operations in the period incurred. Transaction losses of $40 million and $28 million, respectively, were recorded during the years ended December 31, 2023 and 2022.
Implementation of New Financial Accounting Pronouncements	The following table provides a brief description of an accounting standard adopted in the current year: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2020-04, Reference rate reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting; and related amendments ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. ASU 2021-01 clarifies the scope of Topic 848 so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions. ASU 2022-06 extends the period of time entities can utilize the reference rate reform relief guidance under ASU 2020-04 from December 31, 2022 to December 31, 2024. Adoption of the guidance is optional and effective as of March 12, 2020 through December 31, 2024. Adoption is permitted at any time during the period on a prospective basis. Effective April 1, 2023, and in accordance with the provisions outlined in our underlying credit agreements, we have transitioned the reference rate used in our credit facilities from the London Interbank Offered Rate (LIBOR) to the Secured Overnight Financing Rate (Term SOFR). The change did not have a material impact on our consolidated financial statements.
Income Tax	Deferred taxes are recognized for the future tax effects of temporary differences between financial and income tax reporting based on enacted tax laws and rates. The tax benefit from an uncertain tax position is recognized only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such a position are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate resolution. Deferred taxes are not provided on substantially all of the unremitted earnings of subsidiaries outside of the U.S., except where required, because it is expected that these earnings will be reinvested indefinitely. For the amount deemed indefinitely reinvested, it is not practicable to determine the amount of the related deferred income tax liability due to the complexities in the tax laws and assumptions required to be made. Deferred taxes, including U.S. or foreign withholding taxes, would be provided when we no longer consider our subsidiary earnings to be permanently invested, such as in situations where our subsidiaries plan to make future dividend distributions. We treat taxes due on future Global Intangible Low-Taxed Income (GILTI) inclusions in U.S. taxable income as a current period expense when incurred. Certain countries in which we have operations have adopted legislation influenced by the Organization for Economic Co-operation and Development (OECD) Pillar Two rules, including a minimum tax rate of 15%. It is uncertain whether the U.S. will enact legislation to adopt the Pillar Two framework. We are continuing to evaluate additional guidance released by the OECD, along with the pending legislative adoption by additional individual countries.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Description of Accounting Standards Adopted and Not Yet Adopted	The following table provides a brief description of an accounting standard adopted in the current year: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2020-04, Reference rate reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting; and related amendments ASU 2020-04 provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. ASU 2021-01 clarifies the scope of Topic 848 so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions. ASU 2022-06 extends the period of time entities can utilize the reference rate reform relief guidance under ASU 2020-04 from December 31, 2022 to December 31, 2024. Adoption of the guidance is optional and effective as of March 12, 2020 through December 31, 2024. Adoption is permitted at any time during the period on a prospective basis. Effective April 1, 2023, and in accordance with the provisions outlined in our underlying credit agreements, we have transitioned the reference rate used in our credit facilities from the London Interbank Offered Rate (LIBOR) to the Secured Overnight Financing Rate (Term SOFR). The change did not have a material impact on our consolidated financial statements. The following table provides a brief description of accounting standards applicable to us that we have not yet adopted: Standard Description Effective Date Effect on the financial statements or other significant matters ASU 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures ASU 2023-07 is intended to improve disclosure requirements related to reportable segments, primarily through enhanced disclosures about significant segment expenses that are regularly provided to the CODM for purposes of assessing a segment's profit or loss and deciding how to allocate resources. This new standard applies to all public entities, including entities, like us, with a single reportable segment. This new standard is effective for fiscal years beginning after December 31, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. Adoption requires retrospective application. We are currently assessing the impact ASU 2023-07 will have on our consolidated financial statements, including our footnote disclosures. ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures ASU 2023-09 is intended to enhance the transparency and decision usefulness of income tax disclosures by enhancing information about how an entity's operations and related tax risks and its tax planning and operational opportunities affect its tax rate and prospects for future cash flows. The guidance is effective for fiscal years beginning after December 31, 2024, with early adoption permitted. Adoption allows for prospective application, with retrospective application permitted. We are currently assessing the impact ASU 2023-09 will have on our consolidated financial statements, including, but not limited to, our Income Taxes footnote disclosure.

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Summary of Activity in Sales Rebates and Discounts Liability	The following table summarizes the activity in our global sales rebates and discounts liability for the years ended December 31: 2023 2022 Beginning balance $ 324 $ 319 Reduction of revenue 722 682 Payments (683) (662) Foreign currency translation adjustments 4 (15) Ending balance $ 367 $ 324
Disaggregation of Revenue	The following table summarizes our revenue disaggregated by product category for the years ended December 31: 2023 2022 2021 Pet Health $ 2,104 $ 2,138 $ 2,350 Farm Animal: Cattle 949 944 980 Poultry 765 716 744 Swine 382 384 464 Aqua 175 175 144 Total Farm Animal 2,271 2,219 2,332 Contract Manufacturing (1) 42 54 82 Revenue $ 4,417 $ 4,411 $ 4,764 (1) Represents revenue from arrangements in which we manufacture products on behalf of a third party.
Schedule of Revenue Disaggregated by Geographic Area	The following table summarizes our revenue disaggregated by geographic area for the years ended December 31: 2023 2022 2021 United States $ 1,983 $ 1,965 $ 2,124 International 2,434 2,446 2,640 Revenue $ 4,417 $ 4,411 $ 4,764

Acquisitions, Divestitures an_2

Acquisitions, Divestitures and Other Arrangements (Tables)	12 Months Ended
	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Schedule of Purchase Consideration	The composition of the purchase price was as follows: Up-front cash consideration $ 16 Deferred cash consideration paid January 4, 2024 5 Fair value of contingent consideration 38 Total purchase consideration $ 59
Schedule of Fair Value Assets Acquired and Liabilities Assumed	The following table summarizes the fair value of assets acquired as of the acquisition date: Inventories $ 3 Intangible assets: Marketed products 29 Acquired IPR&D 9 Other intangible assets 15 Total identifiable assets 56 Goodwill 3 Total consideration transferred $ 59 Inventories $ 3 Definite-lived intangible assets 15 Total identifiable assets 18 Goodwill 1 Total consideration transferred $ 19 The following table summarizes the fair value of assets acquired and liabilities assumed as of the acquisition date: Cash and cash equivalents $ 31 Other net working capital 13 Property and equipment 33 Intangible assets, primarily acquired IPR&D 333 Deferred income taxes, net (30) Total identifiable net assets 380 Goodwill 35 Settlement of liability related to previous license agreement 29 Total consideration transferred $ 444

Asset Impairment, Restructuri_2

Asset Impairment, Restructuring and Other Special Charges (Tables)	12 Months Ended
	Dec. 31, 2023
Restructuring and Related Activities [Abstract]
Summary of Asset Impairment, Restructuring and Other Special Charges	Components of asset impairment, restructuring and other special charges for the years ended December 31 were as follows: 2023 2022 2021 Restructuring charges (credits) (1) $ — $ (7) $ 110 Acquisition related charges (2) 93 105 162 Non-cash and other items: Asset impairment (3) 32 81 350 Other special charges (4) 2 4 12 Total expense $ 127 $ 183 $ 634 (1) Restructuring credits in 2022 related to adjustments resulting from the reversal of severance accruals associated with 2021 restructuring programs, resulting from final negotiations and certain restructured employees filling open positions. Restructuring charges in 2021 primarily represented employee termination costs for restructuring programs announced and initiated in January and November 2021. These costs were partially offset by the reversal of severance accruals associated with prior restructuring programs during the period. (2) Acquisition related charges primarily included transaction costs directly related to acquiring businesses, such as expenditures for banking, legal, accounting, consulting and other similar services, integration charges inclusive of system and process integration and product transfers, and independent company stand-up costs related to the implementation of new systems, programs and processes. (3) Asset impairments during 2023 included a $26 million write-down of a contract asset related to a long-term manufacturing and supply agreement initially recorded upon the completion of the sale of our Speke site (see Note 4. Acquisitions, Divestitures and Other Arrangements for further discussion on this item) and a write-down of certain indefinite-lived intangible assets, principally due to increases in the relevant discount rates. Asset impairments during 2022 included a charge of $59 million related to the write-off of an IPR&D asset with no alternative future use licensed from BexCaFe and a $22 million charge related to the finalization of the write-down upon sale of the Speke site. Asset impairments in 2021 included write-downs of certain IPR&D and marketed products assets that were subject to product rationalization, as well as write-downs of assets ultimately sold related to the Shawnee and Speke sites. Also included in 2021 are charges recorded to write-down assets in connection with restructuring programs. (4) Other special charges in 2021 primarily represented $10 million of litigation settlements.
Summary of Activity in Reserves	The following table summarizes the activity in our reserves established in connection with restructuring activities: Balance at December 31, 2021 $ 126 Reserve adjustment (9) Cash paid (79) Foreign currency translation adjustments (2) Balance at December 31, 2022 36 Cash paid (29) Balance at December 31, 2023 $ 7

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2023
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories at December 31 consisted of the following: 2023 2022 Finished products $ 857 $ 783 Work in process 814 683 Raw materials and supplies 128 130 Total 1,799 1,596 Decrease to LIFO cost (64) (58) Inventories $ 1,735 $ 1,538

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Long-term Debt	Long-term debt as of December 31 consisted of the following: 2023 2022 Incremental Term Facility due 2025 $ 175 $ 175 Incremental Term Facility due 2028 489 494 Incremental Term Facility due 2029 247 249 Term Loan B due 2027 3,838 3,881 Revolving Credit Facility (1) 200 — Securitization Facility (2) 125 — 4.272% Senior Notes due 2023 (3) — 344 4.900% Senior Notes due 2028 (4) 750 750 TEU Amortizing Notes due 2023 (5) — 7 Unamortized debt issuance costs (50) (64) 5,774 5,836 Less current portion of long-term debt 38 388 Total long-term debt $ 5,736 $ 5,448 (1) Our Revolving Credit Facility provides up to $750 million in borrowing capacity (with incremental capacity if certain conditions are met), bears interest at Term SOFR plus 2.10% and matures in August 2025. In February 2024, we drew an additional $50 million on our Revolving Credit Facility to fund working capital and other operational needs. (2) In August 2023 we entered into a new secured term facility that is secured and collateralized by our U.S. Net Eligible Receivables Balance (see below for further information). In January 2024, we drew an additional $50 million on our Securitization Facility to fund working capital and other operational needs. (3) We redeemed the 4.272% Senior Notes due 2023 in full in August 2023 (see below for further information). (4) Subsequent to issuance in August 2018, the 4.900% Senior Notes due 2028 have been subject to interest rate increases related to credit rating agency downgrades. As of December 31, 2023, these notes bear interest at a rate of 6.650%. (5)
Schedule of Maturities of Long-term Debt	Future required principal payments on our outstanding indebtedness for each of the next five years and thereafter, as of December 31, 2023, were as follows: 2024 $ 50 2025 425 2026 175 2027 3,718 2028 1,221 2029 and thereafter 235 Total obligations and commitments 5,824 Unamortized debt issuance costs (50) Total debt $ 5,774
Cash Payments of Interest Expense and Income Taxes	Cash payments for interest during the years ended December 31 were as follows: 2023 2022 2021 Interest paid $ 379 $ 266 $ 221 Cash payments of income taxes during the years ended December 31, were as follows: 2023 2022 2021 Cash payments of income taxes $ 95 $ 93 $ 151

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Gain (loss), Net of Tax	The amount of net gains (losses) on derivative instruments not designated as hedging instruments, recorded in other expense, net for the years ended December 31, were as follows: 2023 2022 2021 Foreign exchange forward contracts (1) $ 7 $ (12) $ (35) (1) These amounts were substantially offset in other expense, net by the effect of changing exchange rates on the underlying foreign currency exposures. 2023 Cross-currency fixed interest rate swaps $ (72) The amounts of gains on interest rate swap contracts, net of tax, recorded in accumulated other comprehensive loss, for the years ended December 31, were as follows: 2023 2022 2021 Forward-starting interest rate swaps $ — $ 209 $ 58 The amounts of gains (losses) reclassified from accumulated other comprehensive loss and recognized into earnings through interest expense, net of capitalized interest for the years ended December 31, were as follows: 2023 2022 2021 Forward-starting interest rate swaps $ 125 $ 35 $ (28)

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Fair Value Information	The following table summarizes the fair value information at December 31, 2023 and 2022, for assets and liabilities measured at fair value on a recurring basis in the respective balance sheet line items, as well as long-term debt, for which fair value is disclosed on a recurring basis: Fair Value Measurements Using Financial statement line item Carrying Amount Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs Significant Unobservable Inputs Fair Value December 31, 2023 Recurring fair value measurements Prepaid expenses and other - derivative instruments $ 65 $ — $ 65 $ — $ 65 Other current liabilities - derivative instruments (63) — (63) — (63) Other current liabilities - contingent consideration (9) — — (9) (9) Other noncurrent liabilities - derivative instruments (132) — (132) — (132) Other noncurrent liabilities - contingent consideration (31) — — (31) (31) Financial instruments not carried at fair value Long-term debt, including current portion (5,824) — (5,825) — (5,825) December 31, 2022 Recurring fair value measurements Prepaid expenses and other - derivative instruments $ 90 $ — $ 90 $ — $ 90 Other noncurrent assets - derivative instruments 10 — 10 — 10 Other noncurrent assets - investments with readily determinable fair value 7 7 — — 7 Other current liabilities - derivative instruments (64) — (64) — (64) Financial instruments not carried at fair value Long-term debt, including current portion (5,900) — (5,711) — (5,711)

Goodwill and Intangibles (Table

Goodwill and Intangibles (Tables)	12 Months Ended
	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table summarizes the changes in the carrying amount of goodwill: December 31, 2021 $ 6,172 Additions related to the KindredBio acquisition 3 Goodwill associated with Speke divestiture (3) Foreign currency translation adjustments (179) December 31, 2022 5,993 Additions related to acquisitions 4 Impairment charge (1,042) Foreign currency translation adjustments 139 December 31, 2023 $ 5,094
Components of Finite-Lived Intangible Assets	The gross amount of intangible assets and related accumulated amortization, as of December 31, were as follows: 2023 2022 Description Carrying Amount, Gross Accumulated Amortization Carrying Amount, Net Carrying Amount, Gross Accumulated Amortization Carrying Amount, Net Finite-lived intangible assets: Marketed products $ 6,947 $ (2,982) $ 3,965 $ 6,561 $ (2,275) $ 4,286 Software 257 (111) 146 310 (135) 175 Other 71 (35) 36 47 (31) 16 Total finite-lived intangible assets 7,275 (3,128) 4,147 6,918 (2,441) 4,477 Indefinite-lived intangible assets: Acquired IPR&D 339 — 339 359 — 359 Trade names 8 — 8 6 — 6 Total intangible assets: $ 7,622 $ (3,128) $ 4,494 $ 7,283 $ (2,441) $ 4,842 Weighted-Average Life (Years) Marketed products 8 Software 6 Other 6
Components of Indefinite-Lived Intangible Assets	The gross amount of intangible assets and related accumulated amortization, as of December 31, were as follows: 2023 2022 Description Carrying Amount, Gross Accumulated Amortization Carrying Amount, Net Carrying Amount, Gross Accumulated Amortization Carrying Amount, Net Finite-lived intangible assets: Marketed products $ 6,947 $ (2,982) $ 3,965 $ 6,561 $ (2,275) $ 4,286 Software 257 (111) 146 310 (135) 175 Other 71 (35) 36 47 (31) 16 Total finite-lived intangible assets 7,275 (3,128) 4,147 6,918 (2,441) 4,477 Indefinite-lived intangible assets: Acquired IPR&D 339 — 339 359 — 359 Trade names 8 — 8 6 — 6 Total intangible assets: $ 7,622 $ (3,128) $ 4,494 $ 7,283 $ (2,441) $ 4,842
Schedule of Estimated Amortization Expense	The estimated amortization expense for each of the next five years associated with our finite-lived intangible assets, as of December 31, 2023, is as follows: 2024 2025 2026 2027 2028 Estimated amortization expense $ 552 $ 537 $ 529 $ 494 $ 491
Schedule of Impaired Intangible Assets	Impairment charges related to acquired IPR&D included within asset impairment, restructuring and other special charges within our consolidated statements of operations for the years ended December 31, were as follows: 2023 2022 2021 Acquired IPR&D impairment $ 6 $ 59 $ 55

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment and Depreciation Expense	At December 31, property and equipment consisted of the following: 2023 2022 Land $ 40 $ 40 Buildings 630 578 Equipment 985 941 Construction in progress 186 163 1,841 1,722 Less accumulated depreciation (815) (723) Property and equipment, net $ 1,026 $ 999 Property and equipment, less accumulated depreciation, by geographic area as of December 31, was as follows: 2023 2022 United States $ 555 $ 554 Germany 245 224 France 59 52 Other foreign countries 167 169 Property and equipment, net $ 1,026 $ 999 Depreciation expense related to property and equipment for the years ended December 31, was as follows: 2023 2022 2021 Depreciation expense $ 92 $ 89 $ 108

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Operating Leases to Condensed Consolidated Financial Statements	The impact of operating leases to the consolidated financial statements for the years ended December 31, was as follows: 2023 2022 2021 Lease cost Operating lease cost $ 42 $ 45 $ 43 Short-term lease cost 1 1 1 Variable lease cost 4 5 4 Total lease cost $ 47 $ 51 $ 48 Other information Operating cash outflows from operating leases $ 35 $ 33 $ 40 ROU assets obtained in exchange for new operating lease liabilities 28 32 36 Weighted-average remaining lease term - operating leases 7 years 7 years 7 years Weighted-average discount rate - operating leases 4.8 % 4.0 % 3.8 %
Summary of Supplemental Balance Sheet Information Related to Operating Leases	Supplemental balance sheet information related to our operating leases is as follows: Asset/Liability Balance Sheet Classification December 31, 2023 December 31, 2022 Right-of-use assets Other noncurrent assets $ 140 $ 141 Current operating lease liabilities Other current liabilities 32 31 Non-current operating lease liabilities Other noncurrent liabilities 110 111
Schedule of Annual Minimum Lease Payments of Operating Lease Liabilities	As of December 31, 2023, the annual minimum lease payments for our operating lease liabilities for the next five years and thereafter were as follows: 2024 $ 39 2025 30 2026 25 2027 16 2028 10 2029 and thereafter 44 Total lease payments 164 Less imputed interest (22) Total operating lease liabilities $ 142

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of Stock-Based Compensation Expenses	Components of stock-based compensation expense and related tax benefit for the years ended December 31 were as follows: 2023 2022 2021 Total stock-based compensation expense (1) $ 46 $ 59 $ 66 (1) A majority of our stock-based compensation expense relates to RSUs and PAs. The associated tax benefit from stock-based compensation expense was offset by a valuation allowance.
Schedule of Restricted Stock Unit Activity	RSUs granted to employees for the years ended December 31 were as follows: (Units in millions) 2023 2022 2021 Granted units 3.2 1.3 1.1 Weighted-average grant date fair value $ 11.15 $ 28.17 $ 33.57 Changes in the nonvested portion of RSUs for 2023 are summarized below: (Shares in millions) Shares Weighted-Average Grant Date Fair Value Nonvested units at January 1, 2023 2.0 $ 29.40 Granted 3.2 11.15 Vested (1.0) 29.40 Forfeited (0.3) 23.22 Nonvested units at December 31, 2023 3.9 15.49
Schedule of Performance Awards Activity	PA activity during the year ended December 31, 2023, is summarized below: (Shares in millions) Shares Weighted-Average Grant Date Fair Value Nonvested awards at January 1, 2023 0.5 $ 28.94 Granted 1.6 11.25 Vested (0.7) 32.58 Forfeited (0.1) 15.64 Nonvested awards at December 31, 2023 1.3 11.25
Schedule of Assumptions Used	The Black-Scholes-Merton model incorporates a number of valuation assumptions, which are noted in the following table, shown at their weighted-average values for the years ended December 31: 2023 2022 Expected dividend yield (1) — % — % Risk-free interest rate (2) 4.08 % 1.59 % Expected stock price volatility (3) 38.2 % 36.5 % Expected term (4) (years) 6 6 (1) We have never declared nor paid any dividends on our common stock, and we do not anticipate paying dividends on our common stock for the foreseeable future. (2) Determined using the term-matched, zero-coupon risk-free rate from the Treasury Constant Maturity yield curve, continuously compounded. (3) Determined using a leverage-adjusted historical volatility of peer companies. (4) Determined using SEC safe harbor approach, based on a 3-year cliff vesting schedule and 10-year contractual term.
Schedule of Stock Option Activity	Stock option activity during the year ended December 31, 2023, is summarized below: (Shares in millions) Shares of Common Stock Attributable to Options Weighted-Average Exercise Price of Options Weighted-Average Remaining Contractual Term (Years) Aggregate Intrinsic Value (in millions) Outstanding at January 1, 2023 0.8 $ 30.11 Granted 1.1 11.26 Exercised — — Forfeited or expired (0.3) 18.40 Outstanding at December 31, 2023 1.6 $ 17.92 8.4 $ 4 Exercisable at December 31, 2023 0.3 30.86 6.2 —

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Schedule of Composition of Loss Before Income Tax Expense (Benefit)	The composition of loss before income tax expense (benefit) for the years ended December 31, was as follows: 2023 2022 2021 Federal $ (669) $ (350) $ (341) Foreign (526) 278 (230) Loss before income taxes $ (1,195) $ (72) $ (571)
Composition of Income Tax Expense (Benefit)	The composition of income tax expense (benefit) for the years ended December 31, was as follows: 2023 2022 2021 Current: Federal $ (8) $ 11 $ — Foreign 122 51 59 State 2 1 1 Total current tax expense 116 63 60 Deferred: Federal (3) (20) (11) Foreign (66) (36) (136) State (11) (1) (1) Total deferred tax benefit (80) (57) (148) Income tax expense (benefit) $ 36 $ 6 $ (88)
Schedule of Significant Components of Deferred Tax Assets and Liabilities	Significant components of our deferred tax assets and liabilities as of December 31 were as follows: 2023 2022 Deferred tax assets: Compensation and benefits $ 37 $ 32 Accruals and reserves 55 54 Tax credit carryovers 57 53 Tax loss carryovers 314 329 Business interest deduction limitation 196 120 Inventories 24 30 Restructuring and other reserves 7 13 R&D capitalized assets 68 42 Operating lease liabilities 52 34 Deferred loss on derivatives designated as hedges 5 — Other assets — 13 Total gross deferred tax assets 815 720 Valuation allowances (363) (228) Total deferred tax assets 452 492 Deferred tax liabilities: Right-of-use assets (50) (34) Intangibles (837) (920) Property and equipment (74) (70) Deferred gain on derivatives designated as hedges — (42) Other liabilities (5) (6) Total deferred tax liabilities (966) (1,072) Deferred tax liabilities - net $ (514) $ (580)
Schedule of Movements in the Valuation Allowance	Movements in the valuation allowance for the years ended December 31, are summarized as follows: 2023 2022 January 1 $ (228) $ (182) Increase (141) (49) Release 6 3 December 31 $ (363) $ (228)
Schedule of Cash Payments of Interest Expense and Income Taxes	Cash payments for interest during the years ended December 31 were as follows: 2023 2022 2021 Interest paid $ 379 $ 266 $ 221 Cash payments of income taxes during the years ended December 31, were as follows: 2023 2022 2021 Cash payments of income taxes $ 95 $ 93 $ 151
Reconciliation of Income Tax Expense (Benefit)	The following is a reconciliation of the income tax expense (benefit) applying the U.S. federal statutory rate to income before income taxes to reported income tax expense: 2023 2022 2021 Income tax benefit at the U.S. federal statutory tax rate $ (251) $ (15) $ (120) Add (deduct): Taxation of international operations 3 (43) (16) State taxes (12) (11) (8) Income tax credits (10) (13) (14) Non-deductible employee compensation 15 7 4 Goodwill and other asset impairments 164 — — Other permanent adjustments 19 (2) (8) Change in uncertain tax positions 15 3 (2) Change in valuation allowance 93 80 76 Income tax expense (benefit) $ 36 $ 6 $ (88)
Schedule of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits for the years ended December 31, was as follows: 2023 2022 2021 Beginning balance at January 1 $ 16 $ 6 $ 3 Additions based on tax positions related to the current year 2 3 — Changes for tax positions of prior years 13 — (1) Additions related to acquisitions — 7 4 Ending balance at December 31 $ 31 $ 16 $ 6

Retirement Benefits (Tables)

Retirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2023
Retirement Benefits [Abstract]
Schedule of Change in Benefit Obligation, Change in Plan Assets, and Funded Status	We use a measurement date of December 31 to develop the change in benefit obligation, change in plan assets, funded status and amounts recorded on the consolidated balance sheets at December 31 for our defined benefit pension plans, which were as follows: Change in benefit obligation: 2023 2022 Benefit obligation at beginning of year $ 324 $ 462 Service cost 9 14 Interest cost 11 4 Actuarial loss (gain) 17 (123) Benefits paid (14) (12) Foreign currency exchange rate changes and other adjustments 19 (21) Benefit obligation at end of year 366 324 Change in plan assets: Fair value of plan assets at beginning of year 175 207 Actual return on plan assets 8 (26) Employer contribution 11 12 Benefits paid (14) (12) Foreign currency exchange rate changes and other adjustments 12 (6) Fair value of plan assets at end of year 192 175 Funded status (174) (148) Unrecognized net actuarial gain (63) (82) Unrecognized prior service cost (28) (30) Net amount recognized $ (265) $ (260)
Schedule of Amounts Recognized in Combined Balance Sheet	Amounts recognized in the consolidated balance sheet as of December 31, consisted of: Other noncurrent assets $ 1 $ 2 Other current liabilities (1) — Accrued retirement benefits (174) (150) Accumulated other comprehensive loss before income taxes (91) (112) Net amount recognized $ (265) $ (260)
Schedule of Weighted-Average Assumptions Related to Pension Plans	The following represents our weighted-average assumptions related to these pension plans as of and for the years ended December 31: (Percentages) 2023 2022 2021 Discount rate for benefit obligation 2.8 % 3.4 % 1.1 % Discount rate for net benefit costs 3.4 1.1 0.6 Rate of compensation increase for benefit obligation 2.9 3.0 2.7 Rate of compensation increase for net benefit costs 3.0 2.7 3.1 Expected return on plan assets for net benefit costs 4.4 3.1 2.9
Schedule of Expected Benefit Payments	Future benefit payments as of December 31, 2023, which reflect expected future service, as appropriate, are expected to be as follows: 2024 2025 2026 2027 2028 2029-2033 Benefit payments $ 14 $ 15 $ 15 $ 16 $ 16 $ 93
Schedule of Projected Benefit Obligations in Excess of Plan Assets	Amounts relating to pension plans with projected benefit obligations in excess of plan assets were as follows at December 31: 2023 2022 Projected benefit obligation $ 343 $ 301 Fair value of plan assets 168 150
Schedule of Accumulated Benefit Obligations in Excess of Plan Assets	Amounts relating to defined benefit pension plans with accumulated benefit obligations in excess of plan assets were as follows at December 31: 2023 2022 Accumulated benefit obligation $ 332 $ 289 Fair value of plan assets 168 146
Summary of Net Pension Expense (Benefit)	Net pension expense (benefit) related to our defined benefit pension plans for the years ended December 31, included the following components: 2023 2022 2021 Service cost $ 9 $ 14 $ 18 Interest cost 11 4 2 Expected return on plan assets (8) (6) (6) Amortization of prior service cost (5) (5) (6) Amortization of net actuarial (gain) loss (3) 1 2 Net curtailments and settlements — — (29) Net pension expense (benefit) $ 4 $ 8 $ (19)
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	The following represents the pre-tax amounts recognized for defined benefit plans in other comprehensive income (loss) for the years ended December 31, 2023: 2023 2022 2021 Actuarial (loss) gain arising during period $ (17) $ 92 $ 29 Amortization of prior service cost, including settlements, in net loss (5) (5) (36) Amortization of net actuarial (gain) loss, including curtailments, in net loss (3) 1 22 Foreign currency exchange rate changes and other 5 2 — Total other comprehensive (loss) income during period $ (20) $ 90 $ 15
Schedule of Fair Value of Pension Plan Assets	The fair values of pension plan assets as of December 31, 2023, by asset category were as follows: Fair Value Measurements Using Asset Class Total Quoted Prices in Active Markets for Identical Assets Significant Observable Significant Unobservable Inputs Investments Valued at NAV (1) Public equity securities $ 58 $ 55 $ — $ — $ 3 Fixed income: Developed markets 72 71 — — 1 Emerging markets 12 12 — — — Real estate 18 11 7 — — Other 32 28 4 — — Total $ 192 $ 177 $ 11 $ — $ 4 (1) Certain investments measured at fair value using the Net Asset Value (NAV) per share, or its equivalent, as a practical expedient have not been classified in the fair value hierarchy. The fair values of pension plan assets as of December 31, 2022, by asset category were as follows: Fair Value Measurements Using Asset Class Total Quoted Prices in Active Markets for Identical Assets Significant Observable Significant Unobservable Inputs Investments Valued at NAV (1) Public equity securities $ 49 $ 47 $ — $ — $ 2 Fixed income: Developed markets 64 63 — — 1 Emerging markets 9 9 — — — Real estate 23 17 6 — — Other 30 25 5 — — Total $ 175 $ 161 $ 11 $ — $ 3 (1) Certain investments measured at fair value using NAV per share, or its equivalent, as a practical expedient have not been classified in the fair value hierarchy.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Basic And Diluted Loss	Basic and diluted weighted-average shares outstanding were as follows: 2023 2022 2021 Determination of shares: Weighted-average common shares outstanding (1) 492.3 488.3 487.2 Assumed conversion of dilutive common stock equivalents (2) — — — Diluted weighted-average shares outstanding 492.3 488.3 487.2 (1) The TEU prepaid stock purchase contracts were convertible into a minimum of 14.3 million shares or a maximum of 17.2 million shares. The minimum 14.3 million shares were included in the calculation of basic weighted-average shares from January 22, 2020 to February 1, 2023. The 17.2 million shares that were ultimately issued were included in the calculation of basic weighted-average shares subsequent to the settlement date of February 1, 2023. (2) For the years ended December 31, 2023, 2022 and 2021, approximat ely 2.9 million,

Background and Basis of Prese_2

Background and Basis of Presentation (Details)	12 Months Ended
	Dec. 31, 2023 country segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of brands in diverse portfolio (approximately)	200
Number of countries in which entity operates (more than)	90
Number of operating segments | segment	1

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Rebate period		6 months
Accounts receivable, net of allowances	$ 18,000,000	$ 18,000,000	$ 13,000,000
Percentage of weighted average cost inventory			30%
Impairment charge	$ 1,042,000,000	1,042,000,000	$ 0	$ 0
Advertising and promotion expenses		207,000,000	201,000,000	$ 248,000,000
Net loss on foreign currency transactions		$ 40,000,000	$ 28,000,000
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payment term		30 days
Intangible assets useful lives	3 years	3 years
Minimum | Buildings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives	12 years	12 years
Minimum | Equipment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives	3 years	3 years
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Payment term		120 days
Intangible assets useful lives	20 years	20 years
Maximum | Buildings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives	50 years	50 years
Maximum | Equipment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Estimated useful lives	25 years	25 years

Revenue - Summary of Activity i

Revenue - Summary of Activity in Sales Rebates and Discounts Liability (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Change In Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 324	$ 319
Reduction of revenue	722	682
Payments	(683)	(662)
Foreign currency translation adjustments	4	(15)
Ending balance	$ 367	$ 324

Revenue - Narrative (Details)

Revenue - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Concentration Risk [Line Items]
Accounts receivable	$ 842	$ 797
Product Sales
Concentration Risk [Line Items]
Accounts receivable	$ 78	$ 73
Product Return Concentration Risk | Net revenue | Global Customers
Concentration Risk [Line Items]
Concentration risk	1%	1%	1%
Customer Concentration Risk | Revenue | Single Customer
Concentration Risk [Line Items]
Concentration risk	10%	11%	10%

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue	$ 4,417	$ 4,411	$ 4,764
United States
Disaggregation of Revenue [Line Items]
Revenue	1,983	1,965	2,124
International
Disaggregation of Revenue [Line Items]
Revenue	2,434	2,446	2,640
Pet Health
Disaggregation of Revenue [Line Items]
Revenue	2,104	2,138	2,350
Farm Animal
Disaggregation of Revenue [Line Items]
Revenue	2,271	2,219	2,332
Cattle
Disaggregation of Revenue [Line Items]
Revenue	949	944	980
Poultry
Disaggregation of Revenue [Line Items]
Revenue	765	716	744
Swine
Disaggregation of Revenue [Line Items]
Revenue	382	384	464
Aqua
Disaggregation of Revenue [Line Items]
Revenue	175	175	144
Contract Manufacturing
Disaggregation of Revenue [Line Items]
Revenue	$ 42	$ 54	$ 82

Acquisitions, Divestitures an_3

Acquisitions, Divestitures and Other Arrangements - Narrative (Details) $ in Millions				1 Months Ended	12 Months Ended
	Aug. 01, 2023 USD ($)	Jan. 03, 2023 USD ($)	Aug. 27, 2021 USD ($)	Aug. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) employee	Jun. 30, 2022 USD ($)
Business Acquisition [Line Items]
Revenue						$ 4,417	$ 4,411	$ 4,764
Finite-lived intangible assets						4,147	4,477
Liabilities						8,139	8,202
Variable Interest Entity, Primary Beneficiary | BexCaFe, LLC
Business Acquisition [Line Items]
Liabilities									$ 59
Payment on agreement						13	10
Variable Interest Entity, Primary Beneficiary | BexCaFe, LLC | Acquired IPR&D
Business Acquisition [Line Items]
Finite-lived intangible assets									59
Variable Interest Entity, Primary Beneficiary | BexCaFe, LLC | Future Milestone Payments And Sales Royalties
Business Acquisition [Line Items]
Liabilities						35			$ 49
Speke Site
Business Acquisition [Line Items]
Contract with customer, asset, before allowance for credit loss						14	55
Asset impairment						26
Disposal group
Business Acquisition [Line Items]
Number of employees transferred | employee								600
Disposal group | Microbiome R&D Platform Carve-Out
Business Acquisition [Line Items]
Gain on disposal							3
Disposal group | Shawnee And Speke
Business Acquisition [Line Items]
Duration over which proceeds will be received								3 years
Net receivable						69
Disposal group | Shawnee And Speke | Forecast
Business Acquisition [Line Items]
Divestiture proceeds					$ 66
Additional proceeds				$ 3
Disposal group | Shawnee And Speke | TriRx
Business Acquisition [Line Items]
Divestiture proceeds							$ 13
NutriQuest, LLC
Business Acquisition [Line Items]
Consideration paid for acquisition		$ 59
Contingent consideration liability						34
Fair value of contingent consideration		$ 38
Average useful life		12 years
Up-front cash consideration		$ 16
NutriQuest, LLC | NutriQuest, LLC
Business Acquisition [Line Items]
Revenue						$ 19
NutriQuest, LLC | Maximum
Business Acquisition [Line Items]
Contingent consideration liability		$ 85
NutriQuest Brazil
Business Acquisition [Line Items]
Consideration paid for acquisition	$ 19
Contingent consideration liability	$ 16
Average useful life	9 years
Up-front cash consideration	$ 3
KindredBio
Business Acquisition [Line Items]
Up-front cash consideration			$ 444
Settlement of liability related to previous license agreement			$ 29

Acquisitions, Divestitures an_4

Acquisitions, Divestitures and Other Arrangements - Schedule of The Composition of The Purchase Consideration (Details) - USD ($) $ in Millions	Aug. 01, 2023	Jan. 03, 2023
NutriQuest, LLC
Business Acquisition [Line Items]
Up-front cash consideration		$ 16
Deferred cash consideration paid January 4, 2024		5
Fair value of contingent consideration		38
Total consideration transferred		$ 59
NutriQuest Brazil
Business Acquisition [Line Items]
Up-front cash consideration	$ 3
Total consideration transferred	$ 19

Acquisitions, Divestitures an_5

Acquisitions, Divestitures and Other Arrangements - Summary of Amounts Recognized for Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Dec. 31, 2023	Aug. 01, 2023	Jan. 03, 2023	Dec. 31, 2022	Dec. 31, 2021	Aug. 27, 2021
Business Acquisition [Line Items]
Goodwill	$ 5,094			$ 5,993	$ 6,172
NutriQuest, LLC
Business Acquisition [Line Items]
Inventories			$ 3
Total identifiable net assets			56
Goodwill			3
Total consideration transferred			59
NutriQuest, LLC | Marketed products
Business Acquisition [Line Items]
Definite-lived intangible assets			29
NutriQuest, LLC | Acquired IPR&D
Business Acquisition [Line Items]
Definite-lived intangible assets			9
NutriQuest, LLC | Other
Business Acquisition [Line Items]
Definite-lived intangible assets			$ 15
NutriQuest Brazil
Business Acquisition [Line Items]
Inventories		$ 3
Definite-lived intangible assets		15
Total identifiable net assets		18
Goodwill		1
Total consideration transferred		$ 19
KindredBio
Business Acquisition [Line Items]
Total identifiable net assets						$ 380
Goodwill						35
Cash and cash equivalents						31
Other net working capital						13
Property and equipment						33
Deferred income taxes, net						(30)
Settlement of liability related to previous license agreement						29
Total consideration transferred						444
KindredBio | Acquired IPR&D
Business Acquisition [Line Items]
Intangible assets, primarily acquired IPR&D						$ 333

Asset Impairment, Restructuri_3

Asset Impairment, Restructuring and Other Special Charges - Component of Asset Impairment, Restructuring and Other Special Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Restructuring Cost and Reserve [Line Items]
Charges	$ 0	$ (7)	$ 110
Transaction costs	93	105	162
Non-cash and other items:
Asset impairment	32	81	350
Other special charges	2	4	12
Total expense	127	183	634
Litigation settlement charges			$ 10
Disposal group | Speke Site
Non-cash and other items:
Asset impairment	$ 26	22
Variable Interest Entity, Primary Beneficiary | BexCaFe, LLC | Acquired IPR&D
Non-cash and other items:
Asset impairment		$ 59

Asset Impairment, Restructuri_4

Asset Impairment, Restructuring and Other Special Charges - Activity in Reserves (Details) - Severance - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Restructuring Reserve [Roll Forward]
Balance at beginning of period	$ 36	$ 126
Reserve adjustment		(9)
Cash paid	(29)	(79)
Foreign currency translation adjustments		(2)
Balance at end of period	$ 7	$ 36

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Finished products	$ 857	$ 783
Work in process	814	683
Raw materials and supplies	128	130
Total	1,799	1,596
Decrease to LIFO cost	(64)	(58)
Inventories	$ 1,735	$ 1,538

Inventories - Narrative (Detail

Inventories - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Inventories valued under the LIFO method	$ 295	$ 288

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended
	Jan. 31, 2020	Dec. 31, 2023	Feb. 01, 2023	Dec. 31, 2022
Class of Stock [Line Items]
Common stock authorized (in shares)		5,000,000,000		5,000,000,000
Common stock outstanding (in shares)		492,845,216		474,237,738
Common stock issued (in shares)		492,845,216		474,237,738
Preferred stock authorized (in shares)		1,000,000,000
Preferred stock issued (in shares)		0
Preferred stock outstanding (in shares)		0
Tangible Equity Unit
Class of Stock [Line Items]
Shares issued upon conversion of prepaid stock purchase contracts (in shares)			17,000,000
Tangible Equity Unit
Class of Stock [Line Items]
Number of shares sold in public offering (in shares)	11,000,000
Offering price (usd per share)	$ 50
Total cash received upon sale closing	$ 528
Equity component	86%
Debt component	14%
Settlement rate			156.25%
Tangible Equity Unit | Maximum
Class of Stock [Line Items]
Average applicable market value necessary to be included in calculation of diluted shares outstanding (usd per share)			$ 32

Debt - Schedule of Long-term De

Debt - Schedule of Long-term Debt (Details) - USD ($) $ in Millions

1 Months Ended

12 Months Ended

Aug. 03, 2023

Aug. 01, 2020

Feb. 26, 2024

Jan. 31, 2024

Jun. 30, 2022

Apr. 30, 2022

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Aug. 31, 2023

Aug. 07, 2023

Aug. 31, 2018

Debt Instrument [Line Items]

Long-term debt, gross

$ 5,824

Unamortized debt issuance costs

(50)

$ (64)

Total debt

5,774

5,836

Current portion of long-term debt

38

388

Total long-term debt

5,736

5,448

Securitization Facility

Debt Instrument [Line Items]

Proceeds from facility

250

0

$ 0

Credit Facility | Secured Debt | Subsequent Event

Debt Instrument [Line Items]

Proceeds from facility

$ 50

Credit Facility | Secured Debt | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

1.75%

Credit Facility | Secured Debt | Incremental Term Facility due 2025

Debt Instrument [Line Items]

Long-term debt, gross

175

175

Credit Facility | Secured Debt | Incremental Term Facility due 2025 | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

1.75%

Credit Facility | Secured Debt | Incremental Term Facility due 2028

Debt Instrument [Line Items]

Long-term debt, gross

489

494

Credit Facility | Secured Debt | Incremental Term Facility due 2029

Debt Instrument [Line Items]

Long-term debt, gross

247

249

Credit Facility | Secured Debt | Incremental Term Facility due 2029 | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

1.75%

Credit Facility | Secured Debt | Securitization Facility

Debt Instrument [Line Items]

Long-term debt, gross

125

0

Proceeds from facility

$ 250

Credit Facility | Secured Debt | Securitization Facility | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

1.25%

Credit Facility | Term B Loan Facility

Debt Instrument [Line Items]

Long-term debt, gross

3,838

3,881

Credit Facility | Revolving credit facility

Debt Instrument [Line Items]

Long-term debt, gross

200

0

Credit facility, maximum borrowing capacity

$ 750

Proceeds from facility

$ 100

Credit Facility | Revolving credit facility | Subsequent Event

Debt Instrument [Line Items]

Proceeds from facility

$ 50

Credit Facility | Revolving credit facility | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

2.10%

Senior Notes | 4.272% Senior Notes due 2023

Debt Instrument [Line Items]

Interest rate

4.272%

4.272%

4.272%

4.272%

Long-term debt, gross

$ 0

344

Senior Notes | Senior Notes due 2028

Debt Instrument [Line Items]

Interest rate

4.90%

Long-term debt, gross

$ 750

750

Senior Notes | TEU Amortizing Notes due 2023

Debt Instrument [Line Items]

Long-term debt, gross

$ 0

$ 7

Senior Notes | 4.272% Senior Notes due 2023

Debt Instrument [Line Items]

Interest rate

4.272%

4.272%

Senior Notes | Senior Notes Due 2028

Debt Instrument [Line Items]

Interest rate

4.90%

Effective interest rate

6.65%

Debt - Maturity of Long-Term De

Debt - Maturity of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
2024	$ 50
2025	425
2026	175
2027	3,718
2028	1,221
2029 and thereafter	235
Total obligations and commitments	5,824
Unamortized debt issuance costs	(50)
Total debt	$ 5,774	$ 5,836

Debt - Narrative (Details)

Debt - Narrative (Details)

1 Months Ended

2 Months Ended

12 Months Ended

Aug. 03, 2023 USD ($)

Apr. 30, 2022 USD ($)

Aug. 12, 2021

Aug. 01, 2020

Feb. 26, 2024 USD ($)

Jan. 31, 2024 USD ($)

Jun. 30, 2022 USD ($)

Apr. 30, 2022 USD ($)

Aug. 31, 2021 USD ($)

Sep. 30, 2023 USD ($)

Dec. 31, 2023 USD ($) covenant

Dec. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Aug. 31, 2023

Aug. 07, 2023

Aug. 31, 2018 USD ($)

Debt Instrument [Line Items]

Percentage of long term debt bearing fixed interest

78%

Long-term debt, gross

$ 5,824,000,000

Loss on extinguishment of debt

0

$ 20,000,000

$ 0

Securitization Facility

Debt Instrument [Line Items]

Proceeds from facility

250,000,000

0

0

Repayments of lines of credit

$ 125,000,000

0

$ 0

Senior Notes | 4.272% Senior Notes due 2023

Debt Instrument [Line Items]

Interest rate

4.272%

4.272%

Senior Notes | 4.272% Senior Notes due 2023

Debt Instrument [Line Items]

Aggregate principal amount

$ 750,000,000

Interest rate

4.272%

4.272%

4.272%

4.272%

4.272%

Long-term debt, gross

$ 0

344,000,000

Amount of debt retired

$ 406,000,000

$ 406,000,000

Loss on extinguishment of debt

17,000,000

Senior Notes | 4.900% Senior Notes Due 2028

Debt Instrument [Line Items]

Aggregate principal amount

$ 750,000,000

Interest rate

4.90%

Secured Debt | Credit Facility

Debt Instrument [Line Items]

Number of financial covenants | covenant

0

Secured Debt | Credit Facility | Subsequent Event

Debt Instrument [Line Items]

Proceeds from facility

$ 50,000,000

Secured Debt | Credit Facility | Securitization Facility

Debt Instrument [Line Items]

Aggregate principal amount

$ 300,000,000

Proceeds from facility

$ 250,000,000

Repayments of lines of credit

$ 125,000,000

Long-term debt, gross

$ 125,000,000

0

Secured Debt | Credit Facility | Incremental Term Facility due 2029

Debt Instrument [Line Items]

Aggregate principal amount

$ 250,000,000

$ 250,000,000

Long-term debt, gross

247,000,000

249,000,000

Secured Debt | Credit Facility | Incremental Term Facility due 2025

Debt Instrument [Line Items]

Aggregate principal amount

$ 175,000,000

Long-term debt, gross

$ 175,000,000

175,000,000

Secured Debt | Credit Facility | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

1.75%

Secured Debt | Credit Facility | Secured Overnight Financing Rate (SOFR) | Securitization Facility

Debt Instrument [Line Items]

Basis points

1.25%

Debt maturity term

3 years

Secured Debt | Credit Facility | Secured Overnight Financing Rate (SOFR) | Incremental Term Facility due 2029

Debt Instrument [Line Items]

Basis points

1.75%

Secured Debt | Credit Facility | Secured Overnight Financing Rate (SOFR) | Incremental Term Facility due 2025

Debt Instrument [Line Items]

Basis points

1.75%

Revolving credit facility | Credit Facility

Debt Instrument [Line Items]

Number of financial covenants | covenant

2

Required EBITDA leverage ratio

7.71

Required EBITDA ratio to cash interest expense

2

Proceeds from facility

$ 100,000,000

Long-term debt, gross

$ 200,000,000

$ 0

Revolving credit facility | Credit Facility | Subsequent Event

Debt Instrument [Line Items]

Proceeds from facility

$ 50,000,000

Revolving credit facility | Credit Facility | Secured Overnight Financing Rate (SOFR)

Debt Instrument [Line Items]

Basis points

2.10%

Farm Credit Term Loan Facility | Credit Facility

Debt Instrument [Line Items]

Basis points

1.75%

Proceeds from facility

$ 500,000,000

Debt - Interest Paid (Details)

Debt - Interest Paid (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Interest paid	$ 379	$ 266	$ 221

Financial Instruments - Narrati

Financial Instruments - Narrative (Details) SFr in Millions, $ in Millions		1 Months Ended	12 Months Ended
	May 01, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2023 CHF (SFr)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrealized gains			$ 90
Proceeds from interest rate swap settlements			$ 57	$ 207	$ 0
Stranded tax benefits reclassified to earnings				17
Weighted-Average
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Effective interest rate			6.40%
Cross-currency fixed interest rate swap | Not Designated as Hedging Instrument
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notional amount (USD, CHF)			$ 891	784
Cross-currency fixed interest rate swap | Designated as Hedging Instrument | Net Investment Hedging
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notional amount (USD, CHF) | SFr							SFr 1,000
Investment income interest			9
Forward-starting interest rate contracts designated as cash flow hedges | Designated as Hedging Instrument | Cash Flow Hedging
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash received for derivative settlement				207
Interest Rate Swap | Designated as Hedging Instrument
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notional amount (USD, CHF)			$ 3,800	$ 3,050
Increase in derivative notional amount during period	$ 750	$ 1,000
Notional amount						$ 3,050

Financial Instruments - Net Gai

Financial Instruments - Net Gain/Loss on Derivative Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cross-currency fixed interest rate swap | Not Designated as Hedging Instrument
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net gain (loss) on derivative instruments	$ 7	$ (12)	$ (35)
Cross-currency fixed interest rate swap | Designated as Hedging Instrument | Net Investment Hedging
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gain, net of tax	(72)
Interest Rate Swap | Designated as Hedging Instrument | Cash Flow Hedging
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gain, net of tax	0	209	58
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	$ 125	$ 35	$ (28)

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value Information (Details) - Recurring - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current portion	$ 0	$ 0
Significant Observable  Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current portion	(5,825)	(5,711)
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current portion	0	0
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current portion	(5,824)	(5,900)
Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current portion	(5,825)	(5,711)
Prepaid expenses and other | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	0	0
Prepaid expenses and other | Significant Observable  Inputs (Level 2) | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	65	90
Prepaid expenses and other | Significant Unobservable Inputs (Level 3) | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	0	0
Prepaid expenses and other | Carrying Amount | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	65	90
Prepaid expenses and other | Fair Value | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	65	90
Other current liabilities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	0
Contingent consideration	0
Other current liabilities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		0
Other current liabilities | Significant Observable  Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	(63)
Contingent consideration	0
Other current liabilities | Significant Observable  Inputs (Level 2) | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		(64)
Other current liabilities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	0
Contingent consideration	(9)
Other current liabilities | Significant Unobservable Inputs (Level 3) | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		0
Other current liabilities | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	(63)
Contingent consideration	(9)
Other current liabilities | Carrying Amount | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		(64)
Other current liabilities | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	(63)
Contingent consideration	(9)
Other current liabilities | Fair Value | Cross-currency fixed interest rate swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		(64)
Other noncurrent liabilities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	0
Contingent consideration	0
Other noncurrent liabilities | Significant Observable  Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	(132)
Contingent consideration	0
Other noncurrent liabilities | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	0
Contingent consideration	(31)
Other noncurrent liabilities | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	(132)
Contingent consideration	(31)
Other noncurrent liabilities | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)	(132)
Contingent consideration	$ (31)
Other noncurrent assets | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other noncurrent assets - investments with readily determinable fair value		7
Other noncurrent assets | Quoted Prices in Active Markets for Identical Assets (Level 1) | Forward-starting interest rate contracts designated as cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		0
Other noncurrent assets | Significant Observable  Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other noncurrent assets - investments with readily determinable fair value		0
Other noncurrent assets | Significant Observable  Inputs (Level 2) | Forward-starting interest rate contracts designated as cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		10
Other noncurrent assets | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other noncurrent assets - investments with readily determinable fair value		0
Other noncurrent assets | Significant Unobservable Inputs (Level 3) | Forward-starting interest rate contracts designated as cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		0
Other noncurrent assets | Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other noncurrent assets - investments with readily determinable fair value		7
Other noncurrent assets | Carrying Amount | Forward-starting interest rate contracts designated as cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		10
Other noncurrent assets | Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other noncurrent assets - investments with readily determinable fair value		7
Other noncurrent assets | Fair Value | Forward-starting interest rate contracts designated as cash flow hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets (liabilities)		$ 10

Fair Value - Narrative (Details

Fair Value - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2023	Jan. 03, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity method investments	$ 26		$ 27
NutriQuest, LLC
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration liability	$ 34
Maximum | NutriQuest, LLC
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Contingent consideration liability		$ 85

Goodwill and Intangibles - Good

Goodwill and Intangibles - Goodwill Activity (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Roll Forward]
Beginning balance		$ 5,993,000,000	$ 6,172,000,000
Additions related to acquisitions		4,000,000	3,000,000
Goodwill associated with Speke divestiture		(3,000,000)
Impairment charge	$ (1,042,000,000)	(1,042,000,000)	0	$ 0
Foreign currency translation adjustments		139,000,000	(179,000,000)
Ending balance	$ 5,094,000,000	$ 5,094,000,000	$ 5,993,000,000	$ 6,172,000,000

Goodwill and Intangibles - Narr

Goodwill and Intangibles - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Impairment charge	$ 1,042,000,000	$ 1,042,000,000	$ 0	$ 0
Acquired IPR&D impairment		6,000,000	59,000,000	55,000,000
Marketed products
Finite-Lived Intangible Assets [Line Items]
Acquired IPR&D impairment				11,000,000
Software
Finite-Lived Intangible Assets [Line Items]
Amortization		$ 54,000,000	$ 65,000,000	$ 52,000,000

Goodwill and Intangibles - Comp

Goodwill and Intangibles - Components of Intangible Assets Other Than Goodwill (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Carrying Amount, Gross	$ 7,275	$ 6,918
Accumulated Amortization	(3,128)	(2,441)
Carrying Amount, Net	4,147	4,477
Total intangible assets:
Carrying Amount, Gross	7,622	7,283
Accumulated Amortization	(3,128)	(2,441)
Carrying Amount, Net	4,494	4,842
Acquired IPR&D
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	339	359
Trade names
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	8	6
Marketed products
Finite-Lived Intangible Assets [Line Items]
Carrying Amount, Gross	6,947	6,561
Accumulated Amortization	(2,982)	(2,275)
Carrying Amount, Net	3,965	4,286
Total intangible assets:
Accumulated Amortization	(2,982)	(2,275)
Software
Finite-Lived Intangible Assets [Line Items]
Carrying Amount, Gross	257	310
Accumulated Amortization	(111)	(135)
Carrying Amount, Net	146	175
Total intangible assets:
Accumulated Amortization	(111)	(135)
Other
Finite-Lived Intangible Assets [Line Items]
Carrying Amount, Gross	71	47
Accumulated Amortization	(35)	(31)
Carrying Amount, Net	36	16
Total intangible assets:
Accumulated Amortization	$ (35)	$ (31)

Goodwill and Intangibles - Rema

Goodwill and Intangibles - Remaining Weighted Average Amortization Periods (Details)	Dec. 31, 2023
Marketed products
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period	8 years
Software
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period	6 years
Other
Finite-Lived Intangible Assets [Line Items]
Remaining amortization period	6 years

Goodwill and Intangibles - Esti

Goodwill and Intangibles - Estimated Amortization Expense (Details) $ in Millions	Dec. 31, 2023 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2024	$ 552
2025	537
2026	529
2027	494
2028	$ 491

Goodwill and Intangibles - Impa

Goodwill and Intangibles - Impairment Charges (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Acquired IPR&D impairment	$ 6	$ 59	$ 55

Property and Equipment - Schedu

Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,841	$ 1,722
Less accumulated depreciation	(815)	(723)
Property and equipment, net	1,026	999
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	40	40
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	630	578
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	985	941
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 186	$ 163

Property and Equipment- Schedul

Property and Equipment- Schedule of Property and Equipment Geographic Area (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment, net	$ 1,026	$ 999
United States
Property, Plant and Equipment [Line Items]
Property and equipment, net	555	554
Germany
Property, Plant and Equipment [Line Items]
Property and equipment, net	245	224
France
Property, Plant and Equipment [Line Items]
Property and equipment, net	59	52
Other foreign countries
Property, Plant and Equipment [Line Items]
Property and equipment, net	$ 167	$ 169

Property and Equipment - Deprec

Property and Equipment - Depreciation Expense and Rental Expense for All Leases (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 92	$ 89	$ 108

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	Dec. 31, 2023 USD ($)
Lessee, Lease, Description [Line Items]
Operating leases, not yet commenced, minimum lease payments	$ 378
Operating leases, not yet commenced, term (in years)	25 years
Minimum
Lessee, Lease, Description [Line Items]
Remaining lease term	1 year
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	15 years

Leases - Impact of Operating Le

Leases - Impact of Operating Leases to Condensed Consolidated Financial Statements (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease cost
Operating lease cost	$ 42	$ 45	$ 43
Short-term lease cost	1	1	1
Variable lease cost	4	5	4
Total lease cost	47	51	48
Other information
Operating cash outflows from operating leases	35	33	40
ROU assets obtained in exchange for new operating lease liabilities	$ 28	$ 32	$ 36
Weighted-average remaining lease term - operating leases	7 years	7 years	7 years
Weighted-average discount rate - operating leases	4.80%	4%	3.80%

Leases - Supplemental Balance S

Leases - Supplemental Balance Sheet Information Related to Operating Leases (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Right-of-use assets	$ 140	$ 141
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other current liabilities	Other current liabilities
Current operating lease liabilities	$ 32	$ 31
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other noncurrent liabilities	Other noncurrent liabilities
Non-current operating lease liabilities	$ 110	$ 111

Leases - Annual Minimum Lease P

Leases - Annual Minimum Lease Payments of Operating Lease Liabilities (Details) $ in Millions	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 39
2025	30
2026	25
2027	16
2028	10
2029 and thereafter	44
Total lease payments	164
Less imputed interest	(22)
Total operating lease liabilities	$ 142

Stock-Based Compensation - Narr

Stock-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		1.1
Weighted-average grant date fair value per stock option (usd per share)		$ 4.93	$ 10.89
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years
Vested in period, fair value		$ 12	$ 29	$ 30
Unrecognized compensation cost		$ 20
Weighted-average remaining requisite service period		16 months
PAs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period, fair value		$ 8	$ 23	$ 22
Unrecognized compensation cost		$ 9
Weighted-average remaining requisite service period		12 months
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		3 years		3 years
Weighted-average remaining requisite service period		17 months
Expiration period		10 years		10 years
Compensation not yet recognized		$ 3
Elanco Stock Compensation Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in shares authorized for stock-based compensation	20
Shares of common stock to be reserved for future issuance (in shares)		40
Stock options granted (in shares)		26.6

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock-Based Compensation Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Elanco Stock Compensation Plans
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 46	$ 59	$ 66

Stock-Based Compensation - Sc_2

Stock-Based Compensation - Schedule of Restricted Stock Unit and Performance Award Activity (Details) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
RSUs
Outstanding Restricted Stock Units
Beginning nonvested balance (in shares)	2
Granted (in shares)	3.2	1.3	1.1
Vested (in shares)	(1)
Forfeited (in shares)	(0.3)
Ending nonvested balance (in shares)	3.9	2
Weighted-Average Restricted Stock Unit Fair Value
Beginning nonvested balance (in dollars per share)	$ 29.40
Granted (in dollars per share)	11.15	$ 28.17	$ 33.57
Vested (in dollars per share)	29.40
Forfeited (in dollars per share)	23.22
Ending nonvested balance (in dollars per share)	$ 15.49	$ 29.40
PAs
Outstanding Restricted Stock Units
Beginning nonvested balance (in shares)	0.5
Granted (in shares)	1.6
Vested (in shares)	(0.7)
Forfeited (in shares)	(0.1)
Ending nonvested balance (in shares)	1.3	0.5
Weighted-Average Restricted Stock Unit Fair Value
Beginning nonvested balance (in dollars per share)	$ 28.94
Granted (in dollars per share)	11.25
Vested (in dollars per share)	32.58
Forfeited (in dollars per share)	15.64
Ending nonvested balance (in dollars per share)	$ 11.25	$ 28.94

Stock-Based Compensation - Sc_3

Stock-Based Compensation - Schedule of Assumptions Used (Details) - Stock options	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	0%	0%
Risk-free interest rate	4.08%	1.59%
Expected stock price volatility	38.20%	36.50%
Expected term (years)	6 years	6 years
Vesting period	3 years		3 years
Expiration period	10 years		10 years

Stock-Based Compensation - Sc_4

Stock-Based Compensation - Schedule of Stock Option Activity (Details) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) $ / shares shares
Shares of Common Stock Attributable to Options
Outstanding at beginning of period (in shares) | shares	0.8
Granted (in shares) | shares	1.1
Exercised (in shares) | shares	0
Forfeited or expired (in shares) | shares	(0.3)
Outstanding at end of period (in shares) | shares	1.6
Exercisable (in shares) | shares	0.3
Weighted-Average Exercise Price of Options
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 30.11
Granted (in dollars per share) | $ / shares	11.26
Exercised (in dollars per share) | $ / shares	0
Forfeited or expired (in dollars per share) | $ / shares	18.40
Outstanding at end of period (in dollars per share) | $ / shares	17.92
Exercisable (in dollars per share) | $ / shares	$ 30.86
Stock Option Activity, Additional Disclosures
Weighted-average remaining contractual term of the outstanding options	8 years 4 months 24 days
Weighted-average remaining contractual term of the exercisable options	6 years 2 months 12 days
Aggregate intrinsic value of outstanding options | $	$ 4
Aggregate intrinsic value of exercisable options | $	$ 0

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Loss Carryforwards [Line Items]
Deferred tax assets, tax credit carryforwards	$ 57	$ 53
Net operating losses and other carryovers	314	329
Net increase in the valuation allowance	93	80	$ 76
Income taxes receivable	149	180
Brazil tax refund amount		16
Unrecognized tax benefits	31	$ 16	$ 6	$ 3
Foreign
Operating Loss Carryforwards [Line Items]
Tax credit carryovers	8
Domestic
Operating Loss Carryforwards [Line Items]
Tax credit carryovers	33
State
Operating Loss Carryforwards [Line Items]
Tax credit carryovers	16
International, State and Federal
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards with indefinite carryforward period	195
International, State and Federal | 2023 to 2041
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards that expire	$ 120

Income Taxes - Composition of I

Income Taxes - Composition of Income (Loss) Before Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Federal	$ (669)	$ (350)	$ (341)
Foreign	(526)	278	(230)
Loss before income taxes	$ (1,195)	$ (72)	$ (571)

Income Taxes - Composition of_2

Income Taxes - Composition of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ (8)	$ 11	$ 0
Foreign	122	51	59
State	2	1	1
Total current tax expense	116	63	60
Deferred:
Federal	(3)	(20)	(11)
Foreign	(66)	(36)	(136)
State	(11)	(1)	(1)
Total deferred tax benefit	(80)	(57)	(148)
Income tax expense (benefit)	$ 36	$ 6	$ (88)

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Compensation and benefits	$ 37	$ 32
Accruals and reserves	55	54
Tax credit carryovers	57	53
Tax loss carryovers	314	329
Business interest deduction limitation	196	120
Inventories	24	30
Restructuring and other reserves	7	13
R&D capitalized assets	68	42
Operating lease liabilities	52	34
Deferred loss on derivatives designated as hedges	5	0
Other assets	0	13
Total gross deferred tax assets	815	720
Valuation allowances	(363)	(228)
Total deferred tax assets	452	492
Deferred tax liabilities:
Right-of-use assets	(50)	(34)
Intangibles	(837)	(920)
Property and equipment	(74)	(70)
Deferred gain on derivatives designated as hedges	0	(42)
Other liabilities	(5)	(6)
Total deferred tax liabilities	(966)	(1,072)
Deferred tax liabilities - net	$ (514)	$ (580)

Income Taxes - Movements in the

Income Taxes - Movements in the Valuation Allowance (Details) - Valuation Allowance, Deferred Tax Asset - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ (228)	$ (182)
Increase	(141)	(49)
Release	6	3
Ending balance	$ (363)	$ (228)

Income Taxes - Cash Payments of

Income Taxes - Cash Payments of Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Cash payments of income taxes	$ 95	$ 93	$ 151

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax benefit at the U.S. federal statutory tax rate	$ (251)	$ (15)	$ (120)
Add (deduct):
Taxation of international operations	3	(43)	(16)
State taxes	(12)	(11)	(8)
Income tax credits	(10)	(13)	(14)
Non-deductible employee compensation	15	7	4
Goodwill and other asset impairments	164	0	0
Other permanent adjustments	19	(2)	(8)
Change in uncertain tax positions	15	3	(2)
Change in valuation allowance	93	80	76
Income tax expense (benefit)	$ 36	$ 6	$ (88)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Gross Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 16	$ 6	$ 3
Additions based on tax positions related to the current year	2	3	0
Changes for tax positions of prior years	13
Changes for tax positions of prior years		0	(1)
Additions related to acquisitions	0	7	4
Ending balance	$ 31	$ 16	$ 6

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) - USD ($)	1 Months Ended
	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Liabilities related to litigation		$ 0	$ 0
New corporate headquarters, estimated total incentive to be funded by TIF		64,000,000
Tax incremental financing, commitment amount				$ 64,000,000
Refund within next three months			$ 15,000,000
Seresto Class Action Lawsuits
Loss Contingencies [Line Items]
Accrual charge	$ 15,000,000
Loss contingency accrual		15,000,000
SEC Regulatory Matters
Loss Contingencies [Line Items]
Loss contingency accrual		$ 12,500,000

Retirement Benefits - Narrative

Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Expected contributions in fiscal year	$ 10
Defined benefit plan, tax amount	3	$ 11	$ 0
Expenses related to employees under defined contribution plans	40	34	$ 39
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation	$ 354	$ 314
Pension Plans | Switzerland
Defined Benefit Plan Disclosure [Line Items]
Percentage of benefit obligation in Switzerland pension plans	92%
Percentage of plan assets in Switzerland pension plans	87%

Retirement Benefits - Change in

Retirement Benefits - Change in Benefit Obligation, Change in Plan Assets, and Funded Status (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in benefit obligation:
Benefit obligation at beginning of year	$ 324	$ 462
Service cost	9	14	$ 18
Interest cost	11	4	2
Actuarial loss (gain)	17	(123)
Benefits paid	(14)	(12)
Foreign currency exchange rate changes and other adjustments	19	(21)
Benefit obligation at end of year	366	324	462
Change in plan assets:
Fair value of plan assets at beginning of year	175	207
Actual return on plan assets	8	(26)
Employer contribution	11	12
Benefits paid	(14)	(12)
Foreign currency exchange rate changes and other adjustments	12	(6)
Fair value of plan assets at end of year	192	175	$ 207
Funded status	(174)	(148)
Unrecognized net actuarial gain	(63)	(82)
Unrecognized prior service cost	(28)	(30)
Net amount recognized	$ (265)	$ (260)

Retirement Benefits - Amounts R

Retirement Benefits - Amounts Recognized in Combined Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Amounts recognized in the consolidated balance sheet as of December 31, consisted of:
Accrued retirement benefits	$ (184)	$ (161)
Pension Plans
Amounts recognized in the consolidated balance sheet as of December 31, consisted of:
Other noncurrent assets	1	2
Other current liabilities	(1)	0
Accrued retirement benefits	(174)	(150)
Accumulated other comprehensive loss before income taxes	(91)	(112)
Net amount recognized	$ (265)	$ (260)

Retirement Benefits - Weighted-

Retirement Benefits - Weighted-Average Assumptions Related to Pension Plans (Details) - Pension Plans	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Discount rate for benefit obligation	2.80%	3.40%	1.10%
Discount rate for net benefit costs	3.40%	1.10%	0.60%
Rate of compensation increase for benefit obligation	2.90%	3%	2.70%
Rate of compensation increase for net benefit costs	3%	2.70%	3.10%
Expected return on plan assets for net benefit costs	4.40%	3.10%	2.90%

Retirement Benefits - Schedule

Retirement Benefits - Schedule of Expected Benefit Payments (Details) - Pension Plans $ in Millions	Dec. 31, 2023 USD ($)
Benefit payments
2024	$ 14
2025	15
2026	15
2027	16
2028	16
2029-2033	$ 93

Retirement Benefits - Projected

Retirement Benefits - Projected Benefit Obligations in Excess of Plan Assets (Details) - Pension Plans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 343	$ 301
Fair value of plan assets	$ 168	$ 150

Retirement Benefits - Accumulat

Retirement Benefits - Accumulated Benefit Obligations in Excess of Plan Assets (Details) - Pension Plans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 332	$ 289
Fair value of plan assets	$ 168	$ 146

Retirement Benefits - Net Pensi

Retirement Benefits - Net Pension Expense (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 9	$ 14	$ 18
Interest cost	11	4	2
Expected return on plan assets	(8)	(6)	(6)
Amortization of prior service cost	(5)	(5)	(6)
Amortization of net actuarial (gain) loss	(3)	1	2
Net curtailments and settlements	0	0	(29)
Net pension expense (benefit)	$ 4	$ 8	$ (19)

Retirement Benefits - Amounts_2

Retirement Benefits - Amounts Recognized in Other Comprehensive Loss (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Actuarial (loss) gain arising during period	$ (17)	$ 92	$ 29
Amortization of prior service cost, including settlements, in net loss	(5)	(5)	(36)
Amortization of net actuarial (gain) loss, including curtailments, in net loss	(3)	1	22
Foreign currency exchange rate changes and other	5	2	0
Total other comprehensive (loss) income during period	$ (20)	$ 90	$ 15

Retirement Benefits - Fair Valu

Retirement Benefits - Fair Value of Pension Plan Assets (Details) - Pension Plans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 192	$ 175	$ 207
Public equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	58	49
Developed markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	72	64
Emerging markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12	9
Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18	23
Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32	30
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	177	161
Quoted Prices in Active Markets for Identical Assets (Level 1) | Public equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55	47
Quoted Prices in Active Markets for Identical Assets (Level 1) | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71	63
Quoted Prices in Active Markets for Identical Assets (Level 1) | Emerging markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12	9
Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11	17
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	28	25
Significant Observable  Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	11	11
Significant Observable  Inputs (Level 2) | Public equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Observable  Inputs (Level 2) | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Observable  Inputs (Level 2) | Emerging markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Observable  Inputs (Level 2) | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7	6
Significant Observable  Inputs (Level 2) | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	5
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) | Public equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) | Emerging markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Significant Unobservable Inputs (Level 3) | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investments Valued at Net Asset Value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4	3
Investments Valued at Net Asset Value | Public equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3	2
Investments Valued at Net Asset Value | Developed markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1	1
Investments Valued at Net Asset Value | Emerging markets
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investments Valued at Net Asset Value | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Investments Valued at Net Asset Value | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0

Earnings Per Share (Details)

Earnings Per Share (Details) - shares shares in Millions	11 Months Ended	12 Months Ended			36 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 31, 2023
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average common shares outstanding (in shares)		492.3	488.3	487.2
Assumed conversion of dilutive common stock equivalents (in shares)		0	0	0
Diluted weighted average shares outstanding (in shares)		492.3	488.3	487.2
Antidilutive shares not included in calculation diluted earnings per share (in shares)		2.9	3.3	3.2
Tangible Equity Unit
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion of tangible equity units (TEUs) into common stock (in shares)	17.2
Minimum | Tangible Equity Unit
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion of tangible equity units (TEUs) into common stock (in shares)		14.3			14.3
Maximum | Tangible Equity Unit
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion of tangible equity units (TEUs) into common stock (in shares)		17.2

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions	1 Months Ended	12 Months Ended
	Feb. 26, 2024 USD ($) position employee	Dec. 31, 2023 USD ($)
Forecast
Subsequent Event [Line Items]
Number of positions eliminated | position	420
Subsequent Event | Minimum
Subsequent Event [Line Items]
Expected cost	$ 50
Subsequent Event | Minimum | Severance
Subsequent Event [Line Items]
Expected cost	40
Subsequent Event | Maximum
Subsequent Event [Line Items]
Expected cost	55
Subsequent Event | Maximum | Severance
Subsequent Event [Line Items]
Expected cost	45
Sale | Aqua Business
Subsequent Event [Line Items]
Revenue		$ 175
Sale | Aqua Business | Subsequent Event
Subsequent Event [Line Items]
Cash received in agreement to divest	$ 1,300
Number of employees | employee	280
Termination fee	$ 55