Regeneron Pharmaceuticals (REGN) 10-K 5 Feb 25 2024 FY Annual report Financial data

Cover

Cover - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Jan. 23, 2025	Jun. 28, 2024
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	000-19034
Entity Registrant Name	REGENERON PHARMACEUTICALS, INC.
Entity Incorporation, State or Country Code	NY
Entity Tax Identification Number	13-3444607
Entity Address, Address Line One	777 Old Saw Mill River Road
Entity Address, City or Town	Tarrytown
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10591-6707
City Area Code	914
Local Phone Number	847-7000
Title of 12(b) Security	Common Stock - par value $.001 per share
Trading Symbol	REGN
Security Exchange Name	NASDAQ
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	false
Entity Shell Company	false
Entity Public Float			$ 113.8
Documents Incorporated by Reference	Specified portions of the Registrant's definitive proxy statement to be filed in connection with solicitation of proxies for its 2025 Annual Meeting of Shareholders are incorporated by reference into Part III of this Form 10-K. Exhibit index is located on pages 87 to 91 of this filing.
Entity Central Index Key	0000872589
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Amendment Flag	false
Class A Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,817,146
Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		107,507,536

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2024
Audit Information [Abstract]
Auditor Firm ID	238
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Florham Park, New Jersey

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents	$ 2,488.2	$ 2,730
Marketable securities	6,524.3	8,114.8
Accounts receivable, net	6,211.9	5,667.3
Inventories	3,087.3	2,580.5
Prepaid expenses and other current assets	349.2	386.6
Total current assets	18,660.9	19,479.2
Marketable securities	8,900.1	5,396.5
Property, plant, and equipment, net	4,599.7	4,146.4
Intangible assets, net	1,148.6	1,038.6
Deferred tax assets	3,314.1	2,575.4
Other noncurrent assets	1,136	444.1
Total assets	37,759.4	33,080.2
Current liabilities:
Accounts payable	789.5	606.6
Accrued expenses and other current liabilities	2,527.1	2,357.9
Deferred revenue	627.7	458.9
Total current liabilities	3,944.3	3,423.4
Long-term debt	1,984.4	1,982.9
Finance lease liabilities	720	720
Deferred revenue	185.7	126.7
Other noncurrent liabilities	1,571.4	854.1
Total liabilities	8,405.8	7,107.1
Commitments and contingencies
Stockholders' equity:
Preferred Stock, par value $.01 per share; 30.0 shares authorized; shares issued and outstanding - none	0	0
Additional paid-in capital	12,855.9	11,354
Retained earnings	31,672.9	27,260.3
Accumulated other comprehensive loss	(7.9)	(80.9)
Treasury Stock, at cost; 28.2 shares in 2024 and 25.5 shares in 2023	(15,167.4)	(12,560.4)
Total stockholders' equity	29,353.6	25,973.1
Total liabilities and stockholders' equity	37,759.4	33,080.2
Class A Stock
Stockholders' equity:
Common stock	0	0
Common Stock
Stockholders' equity:
Common stock	$ 0.1	$ 0.1

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2024	Dec. 31, 2023
LIABILITIES AND STOCKHOLDERS' EQUITY
Preferred Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, shares authorized (in shares)	30,000,000	30,000,000
Preferred Stock, shares issued (in shares)	0	0
Preferred Stock, shares outstanding (in shares)	0	0
Treasury stock (in shares)	28,200,000	25,500,000
Class A Stock
LIABILITIES AND STOCKHOLDERS' EQUITY
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, shares authorized (in shares)	40,000,000	40,000,000
Common Stock, shares issued (in shares)	1,800,000	1,800,000
Common Stock, shares outstanding (in shares)	1,800,000	1,800,000
Common Stock
LIABILITIES AND STOCKHOLDERS' EQUITY
Common Stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, shares authorized (in shares)	320,000,000	320,000,000
Common Stock, shares issued (in shares)	136,000,000	133,100,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues:
Revenue from contract with customer	$ 14,202	$ 13,117.2	$ 12,172.9
Expenses:
Research and development	5,132	4,439	3,592.5
Acquired in-process research and development	101	186.1	255.1
Selling, general, and administrative	2,954.4	2,631.3	2,115.9
Other operating expense (income), net	53.4	(2.1)	(89.9)
Total expenses	10,211.3	9,070.1	7,434
Income from operations	3,990.7	4,047.1	4,738.9
Other income (expense):
Other income (expense), net	844.4	225.2	179.3
Interest expense	(55.2)	(73)	(59.4)
Total other income (expense)	789.2	152.2	119.9
Income before income taxes	4,779.9	4,199.3	4,858.8
Income tax expense	367.3	245.7	520.4
Net income	$ 4,412.6	$ 3,953.6	$ 4,338.4
Net income per share - basic (in dollars per share)	$ 40.90	$ 37.05	$ 40.51
Net income per share - diluted (in dollars per share)	$ 38.34	$ 34.77	$ 38.22
Weighted average shares outstanding - basic (in shares)	107.9	106.7	107.1
Weighted average shares outstanding - diluted (in shares)	115.1	113.7	113.5
Statements of Comprehensive Income
Net income	$ 4,412.6	$ 3,953.6	$ 4,338.4
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on debt securities	73.6	158.2	(213.6)
Loss on foreign currency translation	(0.6)	(0.3)	0
Unrealized gain on cash flow hedges	0	0	1
Comprehensive income	4,485.6	4,111.5	4,125.8
Net product sales
Revenues:
Revenue from contract with customer	7,629.2	7,078	6,893.7
Expenses:
Cost of goods sold and of collaboration and contract manufacturing	1,087.3	932.1	800
Collaboration revenue
Revenues:
Revenue from contract with customer	6,057.8	5,503.1	4,914.1
Other revenue
Revenues:
Revenue from contract with customer	515	536.1	365.1
Cost of collaboration and contract manufacturing
Expenses:
Cost of goods sold and of collaboration and contract manufacturing	$ 883.2	$ 883.7	$ 760.4

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Class A Stock	Class A Stock Common Stock
Beginning Balance (in shares) at Dec. 31, 2021		126.2						1.8
Beginning Balance, treasury (in shares) at Dec. 31, 2021						(19.4)
Beginning Balance at Dec. 31, 2021	$ 18,768.8	$ 0.1	$ 8,087.5	$ 18,968.3	$ (26.2)	$ (8,260.9)		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock for equity awards granted under long-term incentive plans (in shares)		4.8
Issuance of Common Stock for equity awards granted under long-term incentive plans	1,517.4		1,517.4
Common Stock tendered upon exercise of stock options and vesting of restricted stock for employee tax obligations (in shares)		(0.6)
Common Stock tendered upon exercise of stock options and vesting of restricted stock for employee tax obligations	(445.7)		(445.7)
Issuance/distribution of Common Stock for 401(k) Savings Plan (in shares)						0.1
Issuance/distribution of Common Stock for 401(k) Savings Plan	59.7		52.3			$ 7.4
Repurchases of Common Stock (in shares)						(3.3)
Repurchases of Common Stock	(2,099.8)					$ (2,099.8)
Stock-based compensation charges	737.8		737.8
Net income	4,338.4			4,338.4
Other comprehensive income (loss), net of tax	(212.6)				(212.6)
Ending Balance (in shares) at Dec. 31, 2022		130.4						1.8
Beginning Ending, treasury (in shares) at Dec. 31, 2022						(22.6)
Ending Balance at Dec. 31, 2022	22,664	$ 0.1	9,949.3	23,306.7	(238.8)	$ (10,353.3)		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock for equity awards granted under long-term incentive plans (in shares)		3.5
Issuance of Common Stock for equity awards granted under long-term incentive plans	1,152.2		1,152.2
Common Stock tendered upon exercise of stock options and vesting of restricted stock for employee tax obligations (in shares)		(0.8)
Common Stock tendered upon exercise of stock options and vesting of restricted stock for employee tax obligations	(708.4)		(708.4)
Issuance/distribution of Common Stock for 401(k) Savings Plan (in shares)						0.1
Issuance/distribution of Common Stock for 401(k) Savings Plan	74.1		66.6			$ 7.5
Repurchases of Common Stock (in shares)						(3)
Repurchases of Common Stock	(2,214.6)					$ (2,214.6)
Stock-based compensation charges	894.3		894.3
Net income	3,953.6			3,953.6
Other comprehensive income (loss), net of tax	$ 157.9				157.9
Ending Balance (in shares) at Dec. 31, 2023		133.1					1.8	1.8
Beginning Ending, treasury (in shares) at Dec. 31, 2023	(25.5)					(25.5)
Ending Balance at Dec. 31, 2023	$ 25,973.1	$ 0.1	11,354	27,260.3	(80.9)	$ (12,560.4)		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Common Stock for equity awards granted under long-term incentive plans (in shares)		4.1
Issuance of Common Stock for equity awards granted under long-term incentive plans	1,454.6		1,454.6
Common Stock tendered upon exercise of stock options and vesting of restricted stock for employee tax obligations (in shares)		(1.2)
Common Stock tendered upon exercise of stock options and vesting of restricted stock for employee tax obligations	(1,021.3)		(1,021.3)
Issuance/distribution of Common Stock for 401(k) Savings Plan	78.6		71.7			$ 6.9
Repurchases of Common Stock (in shares)						(2.8)
Repurchases of Common Stock	(2,613.9)					$ (2,613.9)
Stock-based compensation charges	996.9		996.9
Net income	4,412.6			4,412.6
Other comprehensive income (loss), net of tax	$ 73				73
Ending Balance (in shares) at Dec. 31, 2024		136					1.8	1.8
Beginning Ending, treasury (in shares) at Dec. 31, 2024	(28.2)					(28.2)
Ending Balance at Dec. 31, 2024	$ 29,353.6	$ 0.1	$ 12,855.9	$ 31,672.9	$ (7.9)	$ (15,167.4)		$ 0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities:
Net income	$ 4,412.6	$ 3,953.6	$ 4,338.4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	482.9	421	341.4
Stock-based compensation expense	982.8	885	725
(Gains) losses on marketable and other securities, net	(118.3)	266.4	36.8
Other non-cash items, net	23.5	(0.1)	368
Deferred income taxes	(757.3)	(837.8)	(746.4)
Acquired in-process research and development in connection with asset acquisition	12.6	0	195
Changes in assets and liabilities:
(Increase) decrease in accounts receivable	(554)	(338.8)	707.8
Increase in inventories	(619.7)	(271.7)	(696.5)
Increase in prepaid expenses and other assets	(407.5)	(120.1)	(148.6)
Increase in deferred revenue	227.8	37.9	32.4
Increase (decrease) in accounts payable, accrued expenses, and other liabilities	735.1	598.6	(138.4)
Total adjustments	7.9	640.4	676.5
Net cash provided by operating activities	4,420.5	4,594	5,014.9
Cash flows from investing activities:
Purchases of marketable and other securities	(16,617.4)	(11,646)	(7,487.9)
Sales or maturities of marketable and other securities	15,027.3	9,442.2	5,550.5
Capital expenditures	(755.9)	(718.6)	(590.1)
Proceeds from sale of property, plant, and equipment	20.1	0	0
Payments for Libtayo intangible asset	(125.7)	(207.8)	(1,026.8)
Acquisitions, net of cash acquired	(16.5)	(54.9)	(230.3)
Net cash used in investing activities	(2,468.1)	(3,185.1)	(3,784.6)
Cash flows from financing activities:
Proceeds from issuance of Common Stock	1,465.3	1,145.5	1,519.5
Payments in connection with Common Stock tendered for employee tax obligations	(1,029.1)	(700.6)	(445.7)
Repurchases of Common Stock	(2,603.3)	(2,235)	(2,082.8)
Other	(33.4)	0	0
Net cash used in financing activities	(2,200.5)	(1,790.1)	(1,009)
Effect of exchange rate changes on cash, cash equivalents, and restricted cash	(0.7)	(0.4)	0
Net (decrease) increase in cash, cash equivalents, and restricted cash	(248.8)	(381.6)	221.3
Cash, cash equivalents, and restricted cash at beginning of period	2,737.8	3,119.4	2,898.1
Cash, cash equivalents, and restricted cash at end of period	2,489	2,737.8	3,119.4
Supplemental disclosure of cash flow information
Cash paid for interest (net of amounts capitalized)	52.6	73.1	53.7
Cash paid for income taxes	$ 743	$ 870.3	$ 1,502.4

Business Overview and Summary o

Business Overview and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Business Overview and Summary of Significant Accounting Policies	Business Overview and Summary of Significant Accounting Policies Organization and Business Regeneron Pharmaceuticals, Inc. and its subsidiaries ("Regeneron," "Company," "we," "us," and "our") is a fully integrated biotechnology company that invents, develops, manufactures, and commercializes medicines for people with serious diseases. The Company's products and product candidates in development are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, neurological diseases, hematologic conditions, infectious diseases, and rare diseases. The Company's research and development efforts have led to numerous products that have received marketing approval. The Company is a party to collaboration and license agreements to develop and commercialize, as applicable, certain products and product candidates (see Note 3). The Company's business is subject to certain risks including, but not limited to, uncertainties relating to conducting research activities, product development, obtaining regulatory approvals, competition, and obtaining and enforcing patents. Segment Reporting The Company operates in one business segment, which includes all activities related to the discovery, development, and commercialization of medicines for serious diseases. The determination of a single business segment is consistent with the consolidated financial information regularly provided to the Company’s chief operating decision maker (“CODM”). The Company’s CODM is its Chief Executive Officer, who reviews and evaluates consolidated net income for purposes of assessing performance, making operating decisions, allocating resources, and planning and forecasting for future periods. In addition to the significant expense categories included within consolidated net income presented on the Company's Consolidated Statements of Operations, see below for disaggregated amounts that comprise research and development expenses: Year Ended December 31, (In millions) 2024 2023 2022 Direct research and development expenses (a) $ 1,588.8 $ 1,295.6 $ 1,042.9 Indirect research and development expenses: Payroll and benefits 1,681.7 1,537.0 1,195.5 Lab supplies and other research and development costs 241.5 210.6 181.0 Occupancy and other operating costs 614.9 518.2 508.5 Total indirect research and development expenses 2,538.1 2,265.8 1,885.0 Clinical manufacturing costs 1,195.9 1,053.9 938.3 Reimbursement of research and development expenses by collaborators (190.8) (176.3) (273.7) Total research and development expenses $ 5,132.0 $ 4,439.0 $ 3,592.5 (a) Direct research and development expenses are comprised primarily of costs paid to third parties for clinical and product development activities, and the portion of research and development expenses incurred by our collaborators that we are obligated to reimburse. Basis of Presentation The consolidated financial statements include the accounts of Regeneron and its wholly-owned subsidiaries. Intercompany balances and transactions are eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform with the current period's presentation. Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates. Concentration of Credit Risk Financial instruments which potentially expose the Company to concentrations of credit risk consist of cash, cash equivalents, certain investments, and accounts receivable. In accordance with the Company's policies, the Company mandates asset diversification and monitors exposure with its counterparties. Concentrations of credit risk with respect to receivables from collaborators (see Note 3) are significant. In addition, concentrations of credit risk with respect to customer accounts receivable are also significant. As of December 31, 2024 and 2023, two individual customers accounted for 79% and 83% of the Company's net trade accounts receivable balances, respectively. The Company has contractual payment terms with each of its collaborators and customers, and the Company monitors their financial performance and credit worthiness so that it can properly assess and respond to any changes in their credit profile. As of and for the years ended December 31, 2024 and 2023, there were no write-offs and allowances of accounts receivable related to credit risk for the Company's collaborators or customers. Significant Accounting Policies Cash and Cash Equivalents The Company considers all highly liquid debt instruments with a maturity of three months or less when purchased to be cash equivalents. The carrying amount reported in the Consolidated Balance Sheet for cash and cash equivalents approximates its fair value. Debt and Equity Securities The Company has an investment policy that includes guidelines on acceptable investment securities, minimum credit quality, maturity parameters, and diversification. The Company invests its cash primarily in debt securities. The Company considers its investments in debt securities to be "available-for-sale," as defined by authoritative guidance issued by the Financial Accounting Standards Board ("FASB"). These assets are carried at fair value and the unrealized gains and losses are included in accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale debt securities are included in other income (expense), net. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss). The Company also has investments in equity securities that are carried at fair value with changes in fair value recognized within other income (expense), net. The Company has elected to measure certain equity investments it holds that do not have readily determinable fair values at cost less impairment, if any, and adjusts for observable price changes in orderly transactions for identical or similar investments of the same issuer within other income (expense), net. Accounts Receivable The Company's trade accounts receivable arise from product sales and represent amounts due from its customers. In addition, the Company records accounts receivable arising from its collaboration and licensing agreements. The Company monitors the financial performance and credit worthiness of its counterparties so that it can properly assess and respond to changes in their credit profile. The Company provides allowances against receivables for estimated losses, if any, that may result from a counterparty's inability to pay. Amounts determined to be uncollectible are written-off against the allowance. Inventories Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of inventory using the first-in, first-out, or FIFO, method. The Company capitalizes inventory costs associated with the Company's products prior to regulatory approval when, based on management's judgment, future commercialization is considered probable and future economic benefit is expected to be realized; otherwise, such costs are expensed. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval. The Company periodically analyzes its inventory levels to identify inventory that may expire prior to expected sale or has a cost basis in excess of its estimated realizable value. In addition, the Company's products are subject to strict quality control and monitoring which the Company performs throughout the manufacturing process. If certain batches or units of product no longer meet quality specifications or become obsolete due to expiration, the Company records a charge to write down such inventory to its estimated realizable value. Property, Plant, and Equipment Property, plant, and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated on a straight-line basis over the estimated useful lives of the assets. Leasehold improvements are amortized over the shorter of the estimated useful lives of the assets or the remaining lease term. Costs of construction of certain long-lived assets include capitalized interest, which is amortized over the estimated useful life of the related asset. Expenditures for maintenance and repairs which do not materially extend the useful lives of the assets are charged to expense as incurred. The cost and accumulated depreciation or amortization of assets retired or sold are removed from the respective accounts, and any gain or loss is recognized within income from operations. The estimated useful lives of property, plant, and equipment are as follows: Building and improvements 10–50 years Laboratory and other equipment 3–10 years Furniture and fixtures 5 years The Company periodically assesses the recoverability of long-lived assets, such as property, plant, and equipment, and evaluates such assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. Leases The Company determines if an arrangement is a lease considering whether there is an identified asset and the contract conveys the right to control its use. Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company may include options to extend or terminate a lease within the lease term when it is reasonably certain that it will exercise that option. The Company accounts for lease components (e.g., rental payments) separately from non-lease components (e.g., common area maintenance costs). Lease liabilities are recognized at the lease commencement date based on the present value of the remaining lease payments, discounted using the rate implicit in the lease. For leases where an implicit rate is not readily determinable, the Company uses its incremental borrowing rate based on information available at the lease commencement date to determine the present value of future lease payments. Lease expense for operating leases is recognized on a straight-line basis over the expected lease term. Acquisitions The Company makes a determination whether a transaction should be accounted for as a business combination or as an asset acquisition. In a business combination, the acquisition method of accounting generally requires that the assets acquired and liabilities assumed be recorded as of the date of the acquisition at their respective fair values. Amounts allocated to acquired in-process research and development are capitalized as indefinite-lived intangible assets. Any excess of the purchase price (consideration transferred) over the fair values of net assets acquired is recorded as goodwill. Contingent consideration obligations are recorded at fair value as of the acquisition date and remeasured each subsequent reporting period until the contingencies have been resolved, with any changes in fair value recorded in Other operating (income) expense, net. If it is determined that the assets acquired do not meet the definition of a business, or if substantially all of the fair value of the assets acquired are concentrated in a single identifiable asset, then the transaction is accounted for as an asset acquisition rather than a business combination. In an asset acquisition, assets acquired are recorded at cost, goodwill is not recognized, and acquired in-process research and development with no alternative future use is charged to expense. Intangible Assets Intangible assets acquired in a business combination are recorded at fair value, while intangible assets acquired in connection with an asset acquisition are recorded at cost. Payments to acquire intangible assets in an asset acquisition may include up-front payments and contingent consideration. With regard to contingent consideration in an asset acquisition, the Company recognizes regulatory milestones upon achievement, royalties in the period in which the underlying sales occur, and sales-based milestones when the milestone is deemed probable by the Company of being achieved. If contingent consideration is recognized subsequent to the acquisition date in an asset acquisition, the amount of such consideration is recorded as an addition to the cost basis of the intangible asset with a cumulative catch-up adjustment for amortization expense as if the additional amount of consideration had been accrued from the outset of the acquisition. Indefinite-lived intangible assets are subject to impairment testing until completion or abandonment of the associated research and development efforts. Definite-lived intangible assets are amortized to Cost of goods sold over the estimated useful lives of the assets based on the pattern in which the economic benefits of the intangible assets are consumed; if that pattern cannot be reliably determined, a straight-line basis is used. Intangible assets are reviewed for recoverability whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. If an indicator of impairment exists, the Company compares the projected undiscounted cash flows to be generated by the asset to the intangible asset's carrying amount. If the projected undiscounted cash flows of the intangible asset are less than the carrying amount, an impairment loss is recognized within operating expenses and the intangible asset is written down to its fair value in the period in which the impairment occurs. Product Revenue Revenue from product sales is recognized at a point in time when the Company's customer is deemed to have obtained control of the product, which generally occurs upon receipt or acceptance by its customer. The amount of revenue the Company recognizes from product sales may vary due to rebates, chargebacks, and discounts provided under governmental and other programs, distribution-related fees, and other sales-related deductions. In order to determine the transaction price, the Company estimates, utilizing the expected value method, the amount of variable consideration to which the Company will be entitled. This estimate is based upon contracts with customers, healthcare providers, payors, and government agencies, statutorily-defined discounts applicable to government-funded programs, historical experience, estimated payor mix, and other relevant factors. The Company reviews its estimates of rebates, chargebacks, and other applicable provisions each period and records any necessary adjustments in the current period's net product sales. • Rebates: The Company's rebates include amounts paid to managed care organizations, group purchasing organizations, state Medicaid programs, and other rebate programs. The Company estimates reductions to product sales for each type of rebate and records an allowance for rebates in the same period in which the related product sales are recognized. The Company's liability for rebates consists of estimates for claims related to the current and prior periods that have not been paid and estimates for claims that will be made related to product that exists in the distribution channel at the end of the period. • Chargebacks and Discounts: The Company's reserves related to discounted pricing to eligible physicians, Veterans' Administration ("VA"), Public Health Services, and others (collectively, "qualified healthcare providers") represent the Company's estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices the Company charges to its customers (i.e., distributors and specialty pharmacies). The Company's customers charge the Company for the difference between what they pay for the products and the discounted selling price to the qualified healthcare providers. The Company estimates reductions to product sales for each type of chargeback and records an allowance for chargebacks in the same period that the related product sales are recognized. The Company's reserve for chargebacks consists of amounts for which it expects to issue credit based on expected sales by its customers to qualified healthcare providers and chargebacks that customers have claimed but for which the Company has not yet issued credit. • Distribution-Related Fees: The Company has written contracts with its customers that include terms for distribution-related fees. The Company estimates and records distribution and related fees due to its customers generally based on gross sales. • Other Sales-Related Deductions : The Company's other sales-related deductions include co-pay assistance programs and product returns. The Company estimates and records other sales-related deductions generally based on gross sales, written contracts, and other relevant factors. Consistent with industry practice, the Company generally offers its customers a limited right to return product purchased directly from the Company, which is principally based upon the product's expiration date. Product returned is generally not resalable given the nature of the Company's products and method of administration. The Company develops estimates for product returns based upon historical experience, shelf life of the product, and other relevant factors. The Company monitors product supply levels in the distribution channel, as well as sales by its customers, using product-specific data provided by its customers. If necessary, the Company's estimates of product returns may be adjusted in the future based on actual returns experience, known or expected changes in the marketplace, or other factors. Collaborative Arrangements The Company has entered into various collaborative arrangements to research, develop, manufacture, and commercialize products and/or product candidates. Although each of these arrangements is unique in nature, such arrangements involve a joint operating activity where both parties are active participants in the activities of the collaboration and exposed to significant risks and rewards dependent on the commercial success of the activities. In arrangements where the Company does not deem its collaborator to be its customer, payments to and from its collaborator are presented in the Company's statement of operations based on the nature of our business operations, the nature of the arrangement, including the contractual terms, and the nature of the payments. In general, the presentation of such amounts is summarized below. Nature/Type of Payment Statement of Operations Presentation Regeneron's share of profits or losses in connection with commercialization of products Collaboration revenue Reimbursement for manufacturing of commercial supplies Collaboration revenue Royalties and/or sales-based milestones earned Collaboration revenue Reimbursement of Regeneron's research and development expenses Reduction to Research and development expense Regeneron's obligation for its share of collaborator's research and development expenses Research and development expense Up-front, opt-in, and development milestone payments; and premiums paid on equity securities Acquired in-process research and development expense Reimbursement of Regeneron's commercialization-related expenses Reduction to Selling, general, and administrative expense Regeneron's obligation for its share of collaborator's commercialization-related expenses Selling, general, and administrative expense Regeneron's obligation to pay collaborator for its share of gross profits when Regeneron is deemed to be the principal Cost of goods sold Up-front and development milestones earned (when there is a combined unit of account which includes a license and providing research and development services) Other operating income In agreements involving multiple goods or services promised to be transferred to the Company's collaborator, the Company assesses, at the inception of the contract, whether each promise represents a separate obligation (i.e., is "distinct"), or whether such promises should be combined as a single unit of account. When the Company has a combined unit of account which includes a license and providing research and development services to its collaborator, recognition of up-front payments and development milestones earned from its collaborator is deferred (as a liability) and recognized over the development period (i.e., over time) typically using an input method on the basis of the Company's research and development costs incurred relative to the total expected cost which determines the extent of the Company's progress toward completion. The Company reviews its estimates each period and makes revisions to such estimates as necessary. When the Company is entitled to reimbursement of all or a portion of the expenses (e.g., research and development expenses) that it incurs under a collaboration, it records those reimbursable amounts in the period in which such costs are incurred. When the Company enters into an arrangement with another party to fund its research and development costs, the Company considers whether the costs that it may be obligated to repay represent a liability within the scope of Accounting Standards Codification ("ASC") 730-20, Research and Development . If the Company concludes that such funding does not represent a substantive and genuine transfer of risk, a liability is recorded. If the Company's collaborator performs research and development work or commercialization-related activities and the parties share the related costs, the Company also recognizes, as expense (e.g., research and development expense or selling, general, and administrative expense, as applicable) in the period when its collaborator incurs such expenses, the portion of the collaborator's expenses that the Company is obligated to reimburse. The Company's collaborators provide the Company with estimated expenses for the most recent fiscal quarter. The estimates are revised, if necessary, in subsequent periods if actual expenses differ from those estimates. Under certain of the Company's collaboration agreements, product sales and cost of sales may be recorded by the Company's collaborators as they are deemed to be the principal in the transaction. In arrangements where the Company: • supplies commercial product to its collaborator, the Company may be reimbursed for its manufacturing costs as commercial product is shipped to the collaborator (however, recognition of such cost reimbursements may be deferred until the product is sold by the Company's collaborator to third-party customers); • shares in any profits or losses arising from the commercialization of such products, the Company records its share of the variable consideration, representing net product sales less cost of goods sold and shared commercialization and other expenses, in the period in which such underlying sales occur and costs are incurred by the collaborator; • receives royalties and/or sales-based milestone payments from its collaborator, the Company recognizes such amounts in the period earned. The Company's collaborators provide it with estimates of product sales and the Company's share of profits or losses, as applicable, for each quarter. The estimates are revised, if necessary, in subsequent periods if the Company's actual share of profits or losses differ from those estimates. Research and Development Expenses Research and development expenses include costs attributable to the conduct of research and development programs, including the cost of salaries, payroll taxes, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, costs related to research collaboration and licensing agreements, clinical trial expenses, the cost of services provided by outside contractors, including services related to the Company's clinical trials, the cost of manufacturing drug for use in research and development, amounts that the Company is obligated to reimburse to collaborators for research and development expenses that they incur, and the allocable portions of facility costs. Costs associated with research and development are expensed. For each clinical trial that the Company conducts, certain clinical trial costs are expensed immediately, while others are expensed over time based on the expected total number of patients in the trial, the rate at which patients enter and remain in the trial, and/or the period over which clinical investigators, contract research organizations ("CROs"), or other third-party service providers are expected to provide services. In the event of early termination of a clinical trial, the Company accrues and recognizes expenses in an amount based on its estimate of the remaining noncancelable obligations associated with the winding-down of the clinical trial, including any applicable penalties. Stock-based Compensation The Company recognizes stock-based compensation expense for equity grants under the Company's long-term incentive plans (including stock options, restricted stock awards, and restricted stock units (both time-based and performance-based)) to employees and non-employee members of the Company's board of directors (as applicable) based on the grant-date fair value of those awards. The grant-date fair value of an award is generally recognized as compensation expense over the award's requisite service period. Stock-based compensation expense also includes an estimate, which is made at the time of grant, of the number of awards that are expected to be forfeited. The forfeiture rate estimate is calculated by considering both historical forfeiture experience and an estimate of expected future forfeitures for currently outstanding unvested awards. This estimate is reviewed at least annually and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company uses the Black-Scholes model to compute the estimated fair value of stock option awards. Additionally, the Company uses a Monte Carlo simulation to compute the estimated fair value of performance-based restricted stock units that are subject to vesting based on the Company’s attainment of pre-established criteria that include a market condition. For performance-based restricted stock units that contain a performance condition, the Company recognizes stock-based compensation expense if and when the Company determines that it is probable the performance condition will be achieved (based on the number of shares expected to be vested and issued). The Company reassesses the probability of achievement at each reporting period and adjusts compensation cost, as necessary. If there are any changes in the Company's probability assessment, the Company recognizes a cumulative catch-up adjustment in the period of the change in estimate, with the remaining unrecognized expense recognized prospectively over the remaining requisite service period. If the Company subsequently determines that the performance criteria are not met or are not expected to be met, any amounts previously recognized as compensation expense are reversed in the period when such determination is made. Income Taxes The provision for income taxes includes U.S. federal, state, local, and foreign taxes. Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the expected future tax consequences of events that have been included in the financial statements or tax returns, including deferred tax assets and liabilities for expected amounts of global intangible low-taxed income ("GILTI") inclusions. Deferred tax assets and liabilities are determined as the difference between the tax basis of assets and liabilities and their respective financial reporting amounts ("temporary differences") at enacted tax rates in effect for the years in which the differences are expected to reverse. A valuation allowance is established for deferred tax assets for which it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company recognizes the financial statement effects of a tax position when management's assessment is that there is more than a 50% probability that the position will be sustained upon examination by a taxing authority based upon its technical merits. Uncertain tax positions are recorded based upon certain recognition and measurement criteria. The Company re-evaluates uncertain tax positions and considers various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, information obtained during in-process audit activities, and changes in facts or circumstances related to a tax position. The Company adjusts the amount of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain tax positions. The Company recognizes interest and penalties related to income tax matters in income tax expense. Per Share Data Basic net income per share is computed by dividing net income by the weighted average number of shares of Common Stock and Class A Stock outstanding. Net income per share is presented on a combined basis, inclusive of Common Stock and Class A Stock outstanding, as each class of stock has equivalent economic rights. Basic net income per share excludes restricted stock until vested. Diluted net income per share includes the potential dilutive effect of common stock equivalents as if such securities were converted or exercised during the period, when the effect is dilutive. Common stock equivalents include outstanding stock options and unvested restricted stock under the Company's long-term incentive plans, which are included under the treasury stock method when dilutive. Recently Issued Accounting Standards Standard/Description Effective Date Impact of Adoption on the Company's Financial Statements ASU 2023-09: In December 2023, the FASB issued amended guidance related to improvements to income tax disclosures . The amendments require annually (i) enhanced disclosures in connection with an entity's effective tax rate reconciliation and (ii) income taxes paid disaggregated by jurisdiction. January 1, 2025 No significant impact expected ASU 2024-03: In November 2024, the FASB issued new guidance which requires disclosure of disaggregated income statement expense information about specific categories (including purchases of inventory, employee compensation, depreciation, and intangible asset amortization) in the notes to financial statements. January 1, 2027 for annual reporting periods and January 1, 2028 for interim reporting periods Currently evaluating impact

Product Sales

Product Sales	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Product Sales	Product Sales Net product sales consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 EYLEA HD ® U.S. $ 1,201.1 $ 165.8 $ — EYLEA ® U.S. 4,767.1 5,719.6 6,264.6 Total EYLEA HD and EYLEA U.S. 5,968.2 5,885.4 6,264.6 Libtayo ® U.S. 787.3 538.8 374.5 Libtayo (a) Rest of world 429.5 324.3 73.0 Total Libtayo Global 1,216.8 863.1 447.5 Praluent ® U.S. 241.7 182.4 130.0 Evkeeza ® U.S. 125.7 77.3 48.6 Inmazeb ® U.S. 76.8 69.8 3.0 $ 7,629.2 $ 7,078.0 $ 6,893.7 (a) Effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide and, as a result, began recording net product sales of Libtayo outside the United States. See Note 3 for further details. As of December 31, 2024 and 2023, the Company had $4.278 billion and $3.888 billion, respectively, of trade accounts receivable that were recorded within Accounts receivable, net. The Company had product sales to certain customers that each accounted for more than 10% of total gross product revenue for the years ended December 31, 2024, 2023, and 2022. Sales to each of these customers as a percentage of the Company's total gross product revenue are as follows: Year Ended December 31, 2024 2023 2022 Besse Medical, a subsidiary of Cencora, Inc. 50 % 51 % 55 % McKesson Corporation 24 % 25 % 28 % Revenue from product sales is recorded net of applicable provisions for rebates, chargebacks, and discounts, distribution-related fees, and other sales-related deductions. Accruals for chargebacks and discounts are recorded as a direct reduction to accounts receivable. Accruals for rebates, distribution-related fees, and other sales-related deductions are recorded within accrued liabilities. The following table summarizes the provisions, and credits/payments, for sales-related deductions: (In millions) Rebates, Chargebacks, Distribution- Other Sales- Total Balance as of December 31, 2021 $ 214.6 $ 80.0 $ 67.6 $ 362.2 Provisions 1,537.3 431.1 141.1 2,109.5 Credits/payments (1,398.0) (399.7) (127.2) (1,924.9) Balance as of December 31, 2022 353.9 111.4 81.5 546.8 Provisions 2,074.5 439.2 155.3 2,669.0 Credits/payments (1,972.7) (388.3) (157.5) (2,518.5) Balance as of December 31, 2023 455.7 162.3 79.3 697.3 Provisions 2,447.3 462.7 143.0 3,053.0 Credits/payments (2,363.9) (497.2) (128.8) (2,989.9) Balance as of December 31, 2024 $ 539.1 $ 127.8 $ 93.5 $ 760.4

Collaboration, License, and Oth

Collaboration, License, and Other Agreements	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Collaboration, License, and Other Agreements	Collaboration, License, and Other Agreements a. Sanofi Amounts recognized in the Company's Statements of Operations in connection with its collaborations with Sanofi are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Antibody: Regeneron's share of profits Collaboration revenue $ 3,923.5 $ 3,136.5 $ 2,082.0 * Sales-based milestones earned Collaboration revenue $ — $ 50.0 $ 100.0 Reimbursement for manufacturing of commercial supplies Collaboration revenue $ 607.9 $ 613.0 $ 633.7 Other Collaboration revenue $ — $ — $ 28.7 Regeneron's obligation for its share of Sanofi R&D expenses, net of reimbursement of R&D expenses (R&D expense)/Reduction of R&D expense $ (46.8) $ (83.7) $ 43.0 Reimbursement of commercialization-related expenses Reduction of SG&A expense $ 655.4 $ 534.4 $ 437.4 Immuno-oncology (a) : Regeneron's share of profits in connection with commercialization of Libtayo outside the United States Collaboration revenue $ — $ — $ 6.7 Reimbursement for manufacturing of ex-U.S. commercial supplies Collaboration revenue $ — $ — $ 4.6 Reimbursement of R&D expenses Reduction of R&D expense $ — $ — $ 42.7 Reimbursement of commercialization-related expenses, net of Regeneron's obligation for its share of Sanofi commercialization-related expenses Reduction of SG&A expense $ — $ — $ 21.5 Regeneron's obligation for Sanofi's share of Libtayo U.S. gross profits Cost of goods sold $ — $ — $ (70.1) Amounts recognized in connection with up-front payments received Other operating income $ — $ — $ 35.1 * Net of one-time payment of $56.9 million to Sanofi in connection with the amendment to the Antibody License and Collaboration Agreement (a) As described within the " Immuno-Oncology " section below, effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide. Antibody The Company is party to a global, strategic collaboration with Sanofi to research, develop, and commercialize fully human monoclonal antibodies (the "Antibody Collaboration"), which currently consists of Dupixent ® (dupilumab), Kevzara ® (sarilumab), and itepekimab . Under the terms of the Antibody License and Collaboration Agreement (the "LCA"), Sanofi is generally responsible for funding 80% to 100% of agreed-upon development costs. The Company is obligated to reimburse Sanofi for 30% to 50% of worldwide development expenses that were funded by Sanofi based on the Company's share of collaboration profits from commercialization of collaboration products. Under the terms of the LCA, the Company was required to apply 10% of its share of the profits from the Antibody Collaboration in any calendar quarter to reimburse Sanofi for these development costs. On July 1, 2022, an amendment to the LCA became effective, which had been entered into in connection with our acquisition of exclusive worldwide rights to Libtayo (cemiplimab). Pursuant to this amendment, the percentage of the Company's share of profits used to reimburse Sanofi for such development costs has increased from 10% to 20%. The estimated net present value differential between the 10% repayment rate and the 20% repayment rate was deemed to be contingent consideration attributable to the Company's acquisition of the Libtayo rights described within the " Immuno-Oncology " section below; this portion is recorded as an increase to the Libtayo intangible asset over time as the Company repays such development costs to Sanofi. The Company's contingent reimbursement obligation (i.e., "development balance") to Sanofi under the Antibody Collaboration was approximately $1.635 billion as of December 31, 2024. Sanofi leads commercialization activities for products under the Antibody Collaboration, subject to the Company's right to co-commercialize such products. The Company co-commercializes Dupixent in the United States and in certain countries outside the United States. The parties equally share profits from sales within the United States. The parties share profits outside the United States on a sliding scale based on sales starting at 65% (Sanofi)/35% (Regeneron) and ending at 55% (Sanofi)/45% (Regeneron). In addition to profit sharing, the Company was entitled to receive sales milestone payments from Sanofi. In 2023, the Company earned the final $50.0 million sales-based milestone from Sanofi upon aggregate annual sales of antibodies outside the United States exceeding $3.0 billion on a rolling twelve-month basis. In 2022, the Company earned two $50.0 million sales-based milestones from Sanofi, upon aggregate annual sales of antibodies outside the United States exceeding $2.0 billion and $2.5 billion, respectively, on a rolling twelve-month basis. The Company's significant promised goods and services in connection with the Antibody Collaboration consist of providing research and development services, including the manufacturing of clinical supplies, and providing commercial-related services, including the manufacturing of commercial supplies. The Company recognizes amounts in connection with the Antibody Collaboration based on the amount it has the right to invoice and such amount corresponds directly with the Company's performance to date. The following table summarizes contract balances in connection with the Company's Antibody Collaboration with Sanofi: As of December 31, (In millions) 2024 2023 Accounts receivable, net $ 1,216.2 $ 1,029.1 Deferred revenue $ 571.7 $ 427.7 Immuno-Oncology The Company was previously a party to a collaboration with Sanofi for antibody-based cancer treatments in the field of immuno-oncology, including for the co-development and co-commercialization of Libtayo. The parties shared equally, on an ongoing basis, development and commercialization expenses for Libtayo. The Company had principal control over the development of Libtayo and led commercialization activities in the United States, while Sanofi led commercialization activities outside the United States. The parties shared equally in profits and losses in connection with the commercialization of Libtayo. Effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide. In connection with this agreement, in 2022, the Company made a $900.0 million up-front payment to Sanofi, as well as a $100.0 million regulatory milestone payment. In addition, Sanofi was eligible to earn an aggregate of $100.0 million in Libtayo sales-based milestones, of which it earned $65.0 million in 2022 and $35.0 million in 2023. The Company also pays Sanofi an 11% royalty on net product sales of Libtayo through March 31, 2034. The transaction was accounted for as an asset acquisition and amounts paid to Sanofi in connection with obtaining the worldwide rights to Libtayo, including the up-front payment and any contingent consideration, are recorded as an intangible asset. See Note 8 for additional information related to the intangible asset. b. Bayer The Company is party to a license and collaboration agreement with Bayer for the global development and commercialization of EYLEA 8 mg (aflibercept 8 mg) and EYLEA (aflibercept) outside the United States. Agreed-upon development expenses incurred by the Company and Bayer are generally shared equally. The Company is also obligated to use commercially reasonable efforts to supply clinical and commercial bulk product. Bayer is responsible for commercialization activities outside the United States, and the companies share equally in profits from such sales. Within the United States, the Company is responsible for commercialization and retains profits from such sales. The Company is obligated to reimburse Bayer out of the Company's share of the collaboration profits for 50% of the agreed-upon development expenses that Bayer has incurred in accordance with a formula based on the amount of development expenses that Bayer has incurred and the Company's share of the collaboration profits, or at a faster rate at the Company's option. The Company's contingent reimbursement obligation to Bayer was approximately $315 million as of December 31, 2024. Amounts recognized in the Company's Statements of Operations in connection with its Bayer collaboration are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Regeneron's share of profits Collaboration revenue $ 1,403.3 $ 1,376.4 $ 1,317.4 Reimbursement for manufacturing of ex-U.S. commercial supplies Collaboration revenue $ 95.7 $ 111.1 $ 91.4 One-time payment in connection with change in Japan arrangement Collaboration revenue $ — $ — $ 21.9 Regeneron's obligation for its share of Bayer R&D expenses, net of reimbursement of R&D expenses (R&D expense)/Reduction of R&D expense $ (48.5) $ (44.0) $ 16.7 The following table summarizes contract balances in connection with the Company's Bayer collaboration: As of December 31, (In millions) 2024 2023 Accounts receivable, net $ 349.9 $ 381.7 Deferred revenue $ 216.3 $ 138.2 c. Roche The Company is a party to a collaboration agreement with Roche to develop, manufacture, and distribute the casirivimab and imdevimab antibody cocktail (known as REGEN-COV ® in the United States and Ronapreve ™ in other countries). Under the terms of the collaboration agreement, the Company has the right to distribute the product in the United States while Roche has the right to distribute the product outside the United States. The parties share gross profits from worldwide sales based on a pre-specified formula. Amounts recognized in the Company's Statements of Operations in connection with its Roche collaboration are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Regeneron's share of profits Collaboration revenue $ 1.4 $ 224.3 $ 627.3 Other Collaboration revenue $ — $ (13.3) $ — Reimbursement of research and development expenses from Roche was not material for the years ended December 31, 2024, 2023, and 2022. Contract balances in the Company's Balance Sheets in connection with the Roche collaboration were not material as of December 31, 2024 and 2023. d. Other In addition to the collaboration and license agreements discussed above, the Company has various other collaboration and license agreements that are not individually significant to its operating results or financial condition at this time. Pursuant to the terms of those agreements, the Company may be required to pay, or it may receive, additional amounts contingent upon the occurrence of various future events (e.g., upon the achievement of various development and commercial milestones), which in the aggregate could be significant. The Company may also incur, or get reimbursed for, research and development costs. Acquired In-process Research and Development ("IPR&D") Expenses During the year ended December 31, 2024, the Company recorded as Acquired IPR&D expense a $45.0 million development milestone in connection with the Company's collaboration agreement with Sonoma Biotherapeutics, Inc. During the year ended December 31, 2023, the Company recorded as Acquired IPR&D expense a $100.0 million development milestone in connection with its collaboration agreement with Alnylam Pharmaceuticals, Inc., a $45.0 million up-front payment in connection with its collaboration agreement with Sonoma, and a $30.0 million extension payment under its collaboration agreement with Intellia Therapeutics, Inc. During the year ended December 31, 2022, the Company recorded as Acquired IPR&D expense a $195.0 million charge related to its acquisition of Checkmate Pharmaceuticals, Inc. Royalties The Company has also in-licensed patent and/or technology pursuant to agreements which contain provisions that require the Company to pay royalties, as defined, at rates that range from 0.5% to 12.0%, in the event the Company sells or licenses any proprietary products developed under the respective agreements. As described above, as a result of obtaining worldwide rights to Libtayo, the Company pays Sanofi a royalty on net product sales of Libtayo. In addition, in 2018, the Company and Sanofi entered into a license agreement with Bristol-Myers Squibb Company, E. R. Squibb & Sons, L.L.C., and Ono Pharmaceutical Co., Ltd. to obtain a license under certain patents owned and/or exclusively licensed by one or more of those parties that includes the right to develop and sell Libtayo. Under the agreement, the Company paid royalties of 8.0% on worldwide sales of Libtayo through December 31, 2023, and is obligated to pay royalties of 2.5% from January 1, 2024 through December 31, 2026. For the years ended December 31, 2024, 2023, and 2022, the Company recorded royalty expense (net of reimbursements from collaborators, as applicable) of $82.9 million, $117.6 million, and $84.5 million, respectively, based on product sales under various licensing agreements.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities Marketable securities as of December 31, 2024 and 2023 consist of both available-for-sale debt securities of investment grade issuers (see below and Note 5) as well as equity securities of publicly traded companies (see Note 5). The following tables summarize the Company's investments in available-for-sale debt securities: (In millions) Amortized Unrealized Fair As of December 31, 2024 Cost Basis Gains Losses Value Corporate bonds $ 8,226.9 $ 25.1 $ (31.4) $ 8,220.6 U.S. government and government agency obligations 4,820.5 3.4 (6.9) 4,817.0 Commercial paper 548.3 0.4 — 548.7 Certificates of deposit 380.6 0.5 — 381.1 Asset-backed securities 279.0 0.6 (0.3) 279.3 Sovereign bonds 82.7 0.1 (0.4) 82.4 $ 14,338.0 $ 30.1 $ (39.0) $ 14,329.1 As of December 31, 2023 Corporate bonds $ 6,492.5 $ 10.4 $ (104.9) $ 6,398.0 U.S. government and government agency obligations 4,839.6 2.4 (8.6) 4,833.4 Commercial paper 636.8 0.2 (0.2) 636.8 Certificates of deposit 520.8 0.6 — 521.4 Asset-backed securities 88.2 0.1 (1.2) 87.1 Sovereign bonds 58.1 — (0.9) 57.2 $ 12,636.0 $ 13.7 $ (115.8) $ 12,533.9 The Company classifies its investments in available-for-sale debt securities based on their contractual maturity dates. The available-for-sale debt securities as of December 31, 2024 mature at various dates through December 2029. The fair values of available-for-sale debt securities by contractual maturity consist of the following: As of December 31, (In millions) 2024 2023 Maturities within one year $ 6,524.3 $ 8,114.8 Maturities after one year through five years 7,804.8 4,414.5 Maturities after five years — 4.6 $ 14,329.1 $ 12,533.9 The following table shows the fair value and gross unrealized losses by category and disaggregated by the length of time that the Company's available-for-sale debt securities have been in a continuous unrealized loss position. Less than 12 Months 12 Months or Greater Total (In millions) As of December 31, 2024 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate bonds $ 7,175.8 $ (14.2) $ 1,044.8 $ (17.2) $ 8,220.6 $ (31.4) U.S. government and government agency obligations 4,675.3 (6.2) 141.7 (0.7) 4,817.0 (6.9) Sovereign bonds 63.3 (0.3) 19.1 (0.1) 82.4 (0.4) Asset-backed securities 265.4 (0.3) 13.9 — 279.3 (0.3) $ 12,179.8 $ (21.0) $ 1,219.5 $ (18.0) $ 13,399.3 $ (39.0) As of December 31, 2023 Corporate bonds $ 2,363.3 $ (2.4) $ 4,034.7 $ (102.5) $ 6,398.0 $ (104.9) U.S. government and government agency obligations 4,780.6 (6.0) 52.7 (2.6) 4,833.3 (8.6) Sovereign bonds 12.4 (0.1) 44.8 (0.8) 57.2 (0.9) Commercial paper 636.8 (0.2) — — 636.8 (0.2) Asset-backed securities 61.8 (0.3) 25.3 (0.9) 87.1 (1.2) $ 7,854.9 $ (9.0) $ 4,157.5 $ (106.8) $ 12,012.4 $ (115.8) The unrealized losses on corporate bonds were primarily driven by changes in interest rates. The Company has reviewed its portfolio of available-for-sale debt securities and determined that the decline in fair value below cost did not result from credit-related factors. In addition, the Company does not intend to sell, and it is not more likely than not that the Company will be required to sell, such securities before recovery of their amortized cost bases. With respect to marketable securities, for the years ended December 31, 2024, 2023, and 2022, amounts reclassified from Accumulated other comprehensive loss into Other income (expense), net were related to realized gains/losses on sales of available-for-sale debt securities. For the years ended December 31, 2024, 2023, and 2022, realized gains/losses on sales of marketable securities were not material. The Company recognized interest income of $711.4 million, $495.9 million, and $160.1 million for the years ended December 31, 2024, 2023, and 2022, respectively, in Other income (expense), net.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The table below summarizes the Company's assets and liabilities which are measured at fair value on a recurring basis. The following fair value hierarchy is used to classify assets and liabilities, based on inputs to valuation techniques utilized to measure fair value: • Level 1 - Quoted prices in active markets for identical assets or liabilities • Level 2 - Significant other observable inputs, such as quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-based valuations in which significant inputs used are observable • Level 3 - Significant other unobservable inputs (In millions) Fair Value Measurements at Reporting Date As of December 31, 2024 Fair Value Level 1 Level 2 Level 3 Assets: Cash equivalents $ 1,452.2 $ 1,264.2 $ 188.0 $ — Available-for-sale debt securities: Corporate bonds 8,220.6 — 8,220.6 — U.S. government and government agency obligations 4,817.0 — 4,817.0 — Commercial paper 548.7 — 548.7 — Certificates of deposit 381.1 — 381.1 — Asset-backed securities 279.3 — 279.3 — Sovereign bonds 82.4 — 82.4 — Equity securities (unrestricted) 1,052.1 1,052.1 — — Equity securities (restricted) (a) 43.2 43.2 — — Total assets $ 16,876.6 $ 2,359.5 $ 14,517.1 $ — Liabilities: Contingent consideration $ 52.3 $ — $ — $ 52.3 As of December 31, 2023 Assets: Cash equivalents $ 928.1 $ 6.4 $ 921.7 $ — Available-for-sale debt securities: Corporate bonds 6,398.0 — 6,398.0 — U.S. government and government agency obligations 4,833.4 — 4,833.4 — Commercial paper 636.8 — 636.8 — Certificates of deposit 521.4 — 521.4 — Asset-backed securities 87.1 — 87.1 — Sovereign bonds 57.2 — 57.2 — Equity securities (unrestricted) 864.5 864.5 — — Equity securities (restricted) 112.9 112.9 — — Total assets $ 14,439.4 $ 983.8 $ 13,455.6 $ — Liabilities: Contingent consideration $ 43.7 $ — $ — $ 43.7 (a) Includes equity securities which are subject to transfer restrictions that expire in April 2026 In addition to the investments summarized in the table above, as of December 31, 2024 and 2023, the Company had $159.8 million and $74.3 million, respectively, in equity investments that do not have a readily determinable fair value. These investments are recorded within Other noncurrent assets. Also recorded within Other noncurrent assets as of December 31, 2024 were equity investments of $52.0 million which are measured at fair value based on Level 3 inputs; no such investments were held by the Company as of December 31, 2023. During the year ended December 31, 2024, the Company recorded $117.7 million of net unrealized gains on equity securities in Other income (expense), net. During the years ended December 31, 2023 and 2022, the Company recorded $237.8 million and $39.8 million, respectively, of net unrealized losses on equity securities in Other income (expense), net. In addition, during the year ended December 31, 2023, the Company recorded a write-down of $29.0 million in Other income (expense), net related to the Company's investments in private companies. The fair value of the Company's long-term debt (see Note 10), which was determined based on Level 2 inputs, was estimated to be $1.484 billion and $1.528 billion as of December 31, 2024 and 2023, respectively.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2024
Inventory Disclosure [Abstract]
Inventories	Inventories Inventories consist of the following: As of December 31, (In millions) 2024 2023 Raw materials $ 879.5 $ 789.3 Work-in-process 1,342.3 1,121.8 Finished goods 139.8 147.3 Deferred costs 725.7 522.1 $ 3,087.3 $ 2,580.5 Deferred costs represent the costs of product manufactured and shipped to the Company's collaborators for which recognition of revenue has been deferred. For the years ended December 31, 2024, 2023, and 2022, Cost of goods sold included inventory write-offs and reserves of $126.3 million, $102.3 million, and $258.7 million, respectively. Inventory write-offs and reserves for the year ended December 31, 2022 primarily related to REGEN-COV.

Property, Plant, and Equipment

Property, Plant, and Equipment	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment	Property, Plant, and Equipment Property, plant, and equipment, net consists of the following: As of December 31, (In millions) 2024 2023 Building and improvements $ 2,573.2 $ 2,423.1 Leasehold improvements 154.5 133.9 Laboratory equipment 1,494.5 1,384.5 Computer equipment and software 450.8 389.7 Furniture, office equipment, and other 203.8 165.9 Land 288.2 283.1 Construction in progress 1,721.6 1,345.0 6,886.6 6,125.2 Accumulated depreciation and amortization (2,286.9) (1,978.8) $ 4,599.7 $ 4,146.4 Property, plant, and equipment in the table above includes leased property under the Company's finance lease at its Tarrytown, New York corporate headquarters. See Note 11. Depreciation and amortization expense on property, plant, and equipment was $354.1 million, $328.8 million, and $303.9 million for the years ended December 31, 2024, 2023, and 2022, respectively. As of December 31, 2024 and 2023, $3.884 billion and $3.375 billion, respectively, of the Company's net property, plant, and equipment was located in the United States and $715.9 million and $771.4 million, respectively, was located outside the United States (primarily in Ireland).

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets	Intangible Assets Intangible assets, net consist of the following: As of December 31, 2024 2023 (In millions) Estimated Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross carrying Amount Accumulated Amortization Net Carrying Amount Acquired product rights - Libtayo 13 years $ 1,347.7 $ (254.3) $ 1,093.4 $ 1,119.1 $ (126.7) $ 992.4 Other intangibles 8 years 10.0 (7.6) 2.4 10.0 (6.3) 3.7 Acquired in-process research and development Indefinite 52.8 — 52.8 42.5 — 42.5 $ 1,410.5 $ (261.9) $ 1,148.6 $ 1,171.6 $ (133.0) $ 1,038.6 During the years ended December 31, 2024 and 2023, the Company recorded additions to the Libtayo intangible asset related to contingent consideration due to Sanofi (see Note 3). In addition, during the years ended December 31, 2024 and 2023, the Company recorded indefinite-lived intangible assets in connection with the acquisition of in-process and research and development programs. Amortization expense on intangible assets was $128.9 million, $92.2 million, and $37.6 million for the years ended December 31, 2024, 2023, and 2022, respectively. As of December 31, 2024, assuming no changes in the gross carrying amount of intangible assets, amortization expense is estimated to be approximately $102 million for each of the years ending December 31, 2025 through December 31, 2029.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consist of the following: As of December 31, (In millions) 2024 2023 Accrued payroll and related costs $ 640.9 $ 618.2 Accrued clinical expenses 315.7 292.2 Accrued sales-related costs 786.2 780.8 Income tax-related costs 213.2 11.7 Other accrued expenses and liabilities 571.1 655.0 $ 2,527.1 $ 2,357.9

Debt

Debt	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt a. Senior Notes Long-term debt, net of underwriting discounts and offering expenses (which are being amortized as additional interest expense over the period of issuance through maturity), consists of the following: As of December 31, (In millions) 2024 2023 1.750% Senior Notes due September 2030 $ 1,243.3 $ 1,242.2 2.800% Senior Notes due September 2050 741.1 740.7 $ 1,984.4 $ 1,982.9 Interest on each series of senior notes is payable semi-annually until the applicable maturity dates. Interest expense related to the debt was $44.4 million in each of the years ended December 31, 2024, 2023, and 2022. b. Credit Facility The Company is party to an agreement with a syndicate of lenders (the "Credit Agreement") which provides for a $750.0 million senior unsecured five-year revolving credit facility (the "Credit Facility"). The Credit Agreement includes an option for the Company to elect to increase the commitments under the Credit Facility and/or to enter into one or more tranches of term loans in the aggregate principal amount of up to $500.0 million, subject to the consent of the lenders providing the additional commitments or term loans, as applicable, and certain other conditions. The Credit Agreement also provides a $50.0 million sublimit for letters of credit. Proceeds of the loans under the Credit Facility may be used to finance working capital needs, and for general corporate or other lawful purposes, of Regeneron and its subsidiaries. Regeneron Pharmaceuticals, Inc. has guaranteed all obligations under the Credit Facility. The Credit Agreement includes an option for the Company to elect to extend the maturity date of the Credit Facility beyond December 2027, subject to the consent of the extending lenders and certain other conditions. The Company had no borrowings outstanding under the Credit Facility as of December 31, 2024. The Credit Agreement contains operating covenants and a maximum total leverage ratio financial covenant. The Company was in compliance with all covenants of the Credit Agreement as of December 31, 2024.

Leases

Leases	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Leases	Leases The Company conducts certain of its research, development, and administrative activities at leased facilities. The Company also leases vehicles and other assets. Tarrytown, New York Corporate Headquarters The Company leases laboratory and office facilities for its corporate headquarters in Tarrytown, New York (the "Facility") under the Third Amended and Restated Lease and Remedies Agreement (the "Lease") with BA Leasing BSC, LLC, an affiliate of Banc of America Leasing & Capital, LLC ("BAL"), as lessor, and the Third Amended and Restated Participation Agreement (the "Participation Agreement") with Bank of America, N.A., as administrative agent, and a syndicate of lenders (collectively with BAL, the "Participants"), as rent assignees. The Lease, Participation Agreement, and certain related agreements provide for $720.0 million of lease financing (previously advanced by the Participants in March 2017 in connection with the acquisition by BAL of the Facility and the Company's lease of the Facility from BAL), which matures when the term of the Lease expires in March 2027, at which time all amounts outstanding thereunder will become payable in full. The Company has the option to further extend the maturity date of the Participation Agreement and the term of the Lease for an additional five-year period, subject to the consent of the Participants and certain other conditions. The Company also has the option to (a) purchase the Facility by paying an amount equal to the outstanding principal amount of the Participants' advances under the Participation Agreement, all accrued and unpaid yield thereon, and all other outstanding amounts under the Participation Agreement, Lease, and certain related documents or (b) sell the Facility to a third party on behalf of BAL. Pursuant to the Lease, the Company pays all maintenance, insurance, taxes, and other costs arising out of the use of the Facility. The Company is also required to make monthly payments of basic rent to satisfy the yield payable to the Participants on their outstanding advances under the Participation Agreement. Such advances accrue yield at a variable rate per annum based on the one-month forward-looking Secured Overnight Financing Rate ("SOFR") term rate, plus a spread adjustment, plus an applicable margin that varies with the Company's debt rating and total leverage ratio. The Lease is classified as a finance lease as the Company has the option to purchase the Facility under terms that make it reasonably certain to be exercised. The agreements governing the Lease financing contain financial and operating covenants. Such financial covenants and certain of the operating covenants are substantially similar to the covenants set forth in the Credit Agreement. The Company was in compliance with all such covenants as of December 31, 2024. Aggregate Lease Information Amounts recognized in the Consolidated Balance Sheet related to the Company's leases are included in the table below. As of December 31, (In millions) Classification 2024 2023 Assets: Finance lease right-of-use assets Property, plant, and equipment, net (a) $ 591.2 $ 605.7 Operating lease right-of-use assets Other noncurrent assets (b) 217.4 78.0 $ 808.6 $ 683.7 Liabilities: Finance lease liabilities - noncurrent Finance lease liabilities $ 720.0 $ 720.0 Operating lease liabilities - current Accrued expenses and other current liabilities 30.3 19.0 Operating lease liabilities - noncurrent Other noncurrent liabilities 204.1 68.7 $ 954.4 $ 807.7 (a) Finance lease right-of-use assets were recorded net of accumulated amortization of $148.4 million and $133.9 million as of December 31, 2024 and 2023, respectively. (b) Operating lease right-of-use assets were recorded net of accumulated amortization of $78.4 million and $44.6 million as of December 31, 2024 and 2023, respectively. Lease costs consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Operating lease costs $ 36.5 $ 19.2 $ 12.4 Finance lease costs: Amortization of finance lease right-of-use assets 14.5 14.5 14.5 Interest on finance lease liabilities 46.1 45.0 21.6 Total finance lease costs 60.6 59.5 36.1 Total lease costs $ 97.1 $ 78.7 $ 48.5 Other information related to the Company's leases includes the following: As of December 31, 2024 2023 Weighted-average remaining lease term (in years): Finance leases 2.2 3.2 Operating leases 7.2 7.4 Weighted-average discount rate: Finance leases 5.03% 5.08% Operating leases 5.52% 5.38% Supplemental cash flow information related to the Company's leases includes the following: Year Ended December 31, (In millions) 2024 2023 2022 Cash paid for amounts included in the measurement of operating lease liabilities (included within cash flows from operating activities) $ 41.4 $ 22.5 $ 7.7 Right-of-use assets obtained in exchange for operating lease liabilities $ 188.1 $ 31.9 $ 35.1 The following is a maturity analysis of the Company's lease liabilities as of December 31, 2024: (In millions) Finance Leases Operating Leases Total 2025 $ 38.6 $ 43.1 $ 81.7 2026 36.8 44.8 81.6 2027 729.1 42.6 771.7 2028 — 33.2 33.2 2029 — 30.3 30.3 Thereafter — 96.9 96.9 Total undiscounted lease payments 804.5 290.9 1,095.4 Imputed interest (84.5) (56.5) (141.0) Total lease liabilities $ 720.0 $ 234.4 $ 954.4
Leases	Leases The Company conducts certain of its research, development, and administrative activities at leased facilities. The Company also leases vehicles and other assets. Tarrytown, New York Corporate Headquarters The Company leases laboratory and office facilities for its corporate headquarters in Tarrytown, New York (the "Facility") under the Third Amended and Restated Lease and Remedies Agreement (the "Lease") with BA Leasing BSC, LLC, an affiliate of Banc of America Leasing & Capital, LLC ("BAL"), as lessor, and the Third Amended and Restated Participation Agreement (the "Participation Agreement") with Bank of America, N.A., as administrative agent, and a syndicate of lenders (collectively with BAL, the "Participants"), as rent assignees. The Lease, Participation Agreement, and certain related agreements provide for $720.0 million of lease financing (previously advanced by the Participants in March 2017 in connection with the acquisition by BAL of the Facility and the Company's lease of the Facility from BAL), which matures when the term of the Lease expires in March 2027, at which time all amounts outstanding thereunder will become payable in full. The Company has the option to further extend the maturity date of the Participation Agreement and the term of the Lease for an additional five-year period, subject to the consent of the Participants and certain other conditions. The Company also has the option to (a) purchase the Facility by paying an amount equal to the outstanding principal amount of the Participants' advances under the Participation Agreement, all accrued and unpaid yield thereon, and all other outstanding amounts under the Participation Agreement, Lease, and certain related documents or (b) sell the Facility to a third party on behalf of BAL. Pursuant to the Lease, the Company pays all maintenance, insurance, taxes, and other costs arising out of the use of the Facility. The Company is also required to make monthly payments of basic rent to satisfy the yield payable to the Participants on their outstanding advances under the Participation Agreement. Such advances accrue yield at a variable rate per annum based on the one-month forward-looking Secured Overnight Financing Rate ("SOFR") term rate, plus a spread adjustment, plus an applicable margin that varies with the Company's debt rating and total leverage ratio. The Lease is classified as a finance lease as the Company has the option to purchase the Facility under terms that make it reasonably certain to be exercised. The agreements governing the Lease financing contain financial and operating covenants. Such financial covenants and certain of the operating covenants are substantially similar to the covenants set forth in the Credit Agreement. The Company was in compliance with all such covenants as of December 31, 2024. Aggregate Lease Information Amounts recognized in the Consolidated Balance Sheet related to the Company's leases are included in the table below. As of December 31, (In millions) Classification 2024 2023 Assets: Finance lease right-of-use assets Property, plant, and equipment, net (a) $ 591.2 $ 605.7 Operating lease right-of-use assets Other noncurrent assets (b) 217.4 78.0 $ 808.6 $ 683.7 Liabilities: Finance lease liabilities - noncurrent Finance lease liabilities $ 720.0 $ 720.0 Operating lease liabilities - current Accrued expenses and other current liabilities 30.3 19.0 Operating lease liabilities - noncurrent Other noncurrent liabilities 204.1 68.7 $ 954.4 $ 807.7 (a) Finance lease right-of-use assets were recorded net of accumulated amortization of $148.4 million and $133.9 million as of December 31, 2024 and 2023, respectively. (b) Operating lease right-of-use assets were recorded net of accumulated amortization of $78.4 million and $44.6 million as of December 31, 2024 and 2023, respectively. Lease costs consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Operating lease costs $ 36.5 $ 19.2 $ 12.4 Finance lease costs: Amortization of finance lease right-of-use assets 14.5 14.5 14.5 Interest on finance lease liabilities 46.1 45.0 21.6 Total finance lease costs 60.6 59.5 36.1 Total lease costs $ 97.1 $ 78.7 $ 48.5 Other information related to the Company's leases includes the following: As of December 31, 2024 2023 Weighted-average remaining lease term (in years): Finance leases 2.2 3.2 Operating leases 7.2 7.4 Weighted-average discount rate: Finance leases 5.03% 5.08% Operating leases 5.52% 5.38% Supplemental cash flow information related to the Company's leases includes the following: Year Ended December 31, (In millions) 2024 2023 2022 Cash paid for amounts included in the measurement of operating lease liabilities (included within cash flows from operating activities) $ 41.4 $ 22.5 $ 7.7 Right-of-use assets obtained in exchange for operating lease liabilities $ 188.1 $ 31.9 $ 35.1 The following is a maturity analysis of the Company's lease liabilities as of December 31, 2024: (In millions) Finance Leases Operating Leases Total 2025 $ 38.6 $ 43.1 $ 81.7 2026 36.8 44.8 81.6 2027 729.1 42.6 771.7 2028 — 33.2 33.2 2029 — 30.3 30.3 Thereafter — 96.9 96.9 Total undiscounted lease payments 804.5 290.9 1,095.4 Imputed interest (84.5) (56.5) (141.0) Total lease liabilities $ 720.0 $ 234.4 $ 954.4

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Stockholders' Equity	Stockholders' Equity The Company's Restated Certificate of Incorporation, as amended, provides for the issuance of up to 40 million shares of Class A Stock, par value $0.001 per share, and 320 million shares of Common Stock, par value $0.001 per share. Shares of Class A Stock are convertible, at any time, at the option of the holder into shares of Common Stock on a share-for-share basis. Holders of Class A Stock have rights and privileges identical to Common Stockholders except that each share of Class A is entitled to ten votes per share, while each share of Common Stock is entitled to one vote per share. Class A Stock may only be transferred to specified Permitted Transferees, as defined. Under the Company's Restated Certificate of Incorporation, the Company's board of directors is authorized to issue up to 30 million shares of Preferred Stock, in series, with rights, privileges, and qualifications of each series determined by the board of directors. a. Share Repurchase Programs In November 2021, the Company's board of directors authorized a share repurchase program to repurchase up to $3.0 billion of the Company's Common Stock. As of June 30, 2023, the Company had repurchased the entire $3.0 billion of its Common Stock it was authorized to repurchase under the program. In January 2023, the Company's board of directors authorized a share repurchase program to repurchase up to an additional $3.0 billion of the Company's Common Stock. As of September 30, 2024, the Company had repurchased the entire $3.0 billion of its Common Stock that it was authorized to repurchase under the program. In April 2024, the Company's board of directors authorized a share repurchase program to repurchase up to an additional $3.0 billion of the Company's Common Stock. The share repurchase program permits the Company to make repurchases through a variety of methods, including open-market transactions (including pursuant to a trading plan adopted in accordance with Rule 10b5-1 of the Securities Exchange Act of 1934, as amended (the "Exchange Act")), privately negotiated transactions, accelerated share repurchases, block trades, and other transactions in compliance with Rule 10b-18 of the Exchange Act. The table below summarizes the shares of the Company's Common Stock that the Company repurchased and the cost of such shares, which were recorded as Treasury Stock. Year Ended December 31, (In millions) 2024 2023 2022 Number of shares 2.8 2.9 3.3 Total cost of shares $ 2,613.9 $ 2,214.6 $ 2,099.8 As of December 31, 2024, $1.917 billion remained available for share repurchases under the April 2024 program. In February 2025, the Company's board of directors authorized a share repurchase program to repurchase up to an additional $3.0 billion of the Company's Common Stock. The share repurchase program was approved under terms substantially similar to the repurchase programs described above. b. Dividend In February 2025, the Company's board of directors declared the Company's first quarterly cash dividend, in the amount of $0.88 per share on its Common Stock and Class A Stock. The cash dividend will be payable on March 20, 2025 to shareholders of record as of February 20, 2025.

Long-Term Incentive Plans

Long-Term Incentive Plans	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Long-Term Incentive Plans	Long-Term Incentive Plans The Company has used long-term incentive plans for the purpose of granting equity awards to employees of the Company, including officers, and non-employee members of the Company's board of directors (collectively, "Participants"). The Participants may receive awards as determined by a committee of independent members of the Company's board of directors or, to the extent authorized by such committee with respect to certain Participants, a duly authorized employee (collectively, the "Committee"). The incentive plan currently used by the Company is the Second Amended and Restated Regeneron Pharmaceuticals, Inc. 2014 Long-Term Incentive Plan (the "Second Amended and Restated 2014 Incentive Plan"). It was most recently adopted and approved by the Company's shareholders in 2020. As of the most recent shareholder approval date, the Second Amended and Restated 2014 Incentive Plan provided for the issuance of up to 22.3 million shares of Common Stock in respect of awards. In addition, upon expiration, forfeiture, surrender, exchange, cancellation, or termination of any award previously granted under the Amended and Restated Regeneron Pharmaceuticals, Inc. 2014 Long-Term Incentive Plan (the "Amended and Restated 2014 Incentive Plan"), the Regeneron Pharmaceuticals, Inc. 2014 Long-Term Incentive Plan (the "Original 2014 Incentive Plan"), or the Second Amended and Restated 2000 Long-Term Incentive Plan (the "2000 Incentive Plan"), any shares subject to such award are added to the pool of shares available for grant under the Second Amended and Restated 2014 Incentive Plan. The awards that may be made under the Second Amended and Restated 2014 Incentive Plan include: (a) non-qualified stock options and incentive stock options, (b) restricted stock awards, (c) shares of phantom stock (also referred to as restricted stock units, which may be time- or performance-based), and (d) other awards. Any award granted may (but is not required to) be subject to vesting based on the attainment by the Company of performance goals pre-established by the Committee. Stock option awards grant Participants the right to purchase shares of Common Stock at prices determined by the Committee, with exercise prices that are equal to or greater than the average of the high and low market prices of the Company's Common Stock on the date of grant (the "Market Price"). Options vest over a period of time determined by the Committee, generally on a pro rata basis over a four-year period. The Committee also determines the expiration date of each option. The maximum term of options that have been awarded under the 2000 Incentive Plan, the Original 2014 Incentive Plan, the Amended and Restated 2014 Incentive Plan, and the Second Amended and Restated 2014 Incentive Plan (collectively, the "Incentive Plans") is ten years. Restricted stock awards grant Participants shares of restricted Common Stock. Such shares are nontransferable for a period determined by the Committee ("vesting period"). Should employment terminate, as specified in the Incentive Plans, except as determined by the Committee in its discretion and subject to the applicable Incentive Plan documents, the ownership of any unvested restricted stock awards will be transferred to the Company. Phantom stock awards provide the Participant the right to receive Common Stock or an amount of cash based on the value of the Common Stock at a future date. The award is subject to such restrictions, if any, as the Committee may impose at the date of grant or thereafter, including a specified period of employment or the achievement of performance goals. Time-based restricted stock units and performance-based restricted stock units are each a type of phantom stock award permitted under the Second Amended and Restated 2014 Incentive Plan. The Incentive Plans contain provisions that allow for the Committee to provide for the immediate vesting of awards upon a change in control of the Company, as defined in the Incentive Plans. As of December 31, 2024, there were 13.1 million shares available for future grants under the Second Amended and Restated 2014 Incentive Plan. a. Stock Options The table below summarizes the activity related to stock option awards under the Company's Incentive Plans during 2024. Number of Shares (In millions) Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Intrinsic Value (In millions) Outstanding as of December 31, 2023 14.2 $ 534.13 2024: Granted 1.9 $ 786.79 Forfeited (0.2) $ 698.92 Exercised (3.2) $ 454.70 Outstanding as of December 31, 2024 12.7 $ 588.47 6.1 years $ 1,891.0 Vested and expected to vest as of December 31, 2024 12.3 $ 582.36 6.0 years $ 1,888.5 Exercisable as of December 31, 2024 8.3 $ 495.19 4.7 years $ 1,834.8 The Company satisfies stock option exercises with newly issued shares of the Company's Common Stock. The total intrinsic value of stock options exercised during 2024, 2023, and 2022 was $1.682 billion, $1.096 billion, and $1.214 billion, respectively. The intrinsic value represents the amount by which the market price of the underlying stock exceeds the exercise price of an option. The table below summarizes the weighted-average exercise prices and weighted-average grant-date fair values of options issued during the years ended December 31, 2024, 2023, and 2022. Number of Options Granted (In millions) Weighted-Average Exercise Price Weighted-Average Fair Value 2024: Exercise price equal to Market Price 1.9 $ 786.79 $ 235.32 2023: Exercise price equal to Market Price 1.6 $ 835.91 $ 264.37 2022: Exercise price equal to Market Price 2.0 $ 705.02 $ 220.88 For the years ended December 31, 2024, 2023, and 2022, the Company recognized $376.0 million, $357.1 million, and $341.9 million, respectively, of stock-based compensation expense related to stock option awards (net of amounts capitalized as inventory, which were not material for each of the three years). As of December 31, 2024, there was $626.7 million of stock-based compensation cost related to unvested stock options, net of estimated forfeitures, which had not yet been recognized. The Company expects to recognize this compensation cost over a weighted-average period of 1.9 years. Fair Value Assumptions: The following table summarizes the weighted average values of the assumptions used in computing the fair value of option grants during 2024, 2023, and 2022. 2024 2023 2022 Expected volatility 25 % 26 % 28 % Expected lives from grant date 5.0 years 5.1 years 5.2 years Expected dividend yield 0 % 0 % 0 % Risk-free interest rate 4.11 % 4.29 % 3.50 % Expected volatility has been estimated based on actual movements in the Company's stock price over the most recent historical periods equivalent to the options' expected lives. Expected lives are principally based on the Company's historical exercise experience with previously issued employee and board of directors' option grants. During 2024, 2023, and 2022, the expected dividend yield was zero as the Company had not paid dividends nor did it expect to at the time of option grants. The risk-free interest rates are based on quoted U.S. Treasury rates for securities with maturities approximating the options' expected lives. b. Restricted Stock Awards and Time-Based Restricted Stock Units A summary of the Company's activity related to restricted stock awards and time-based restricted stock units (excluding performance-based restricted stock units, which are detailed further below) (collectively, "restricted stock") during 2024 is summarized below. Number of Shares/Units (In millions) Weighted-Average Grant Unvested as of December 31, 2023 2.3 $ 705.37 2024: Granted 1.0 $ 787.15 Vested (0.7) $ 617.50 Forfeited (0.1) $ 704.57 Unvested as of December 31, 2024 2.5 $ 760.35 For the years ended December 31, 2024, 2023, and 2022, the Company recognized $554.7 million, $475.9 million, and $331.1 million, respectively, of stock-based compensation expense related to restricted stock (net of amounts capitalized as inventory, which were not material for each of the three years). As of December 31, 2024, there was $1.219 billion of stock-based compensation cost related to unvested restricted stock which had not yet been recognized. The Company expects to recognize this compensation cost over a weighted-average period of 2.3 years. c. Performance-based Restricted Stock Units Performance-based restricted stock units ("PSUs") have been granted to certain members of senior management of the Company. PSUs may be earned based upon the attainment of pre-established performance criteria, which may include a market and/or performance condition. Depending on the terms of the PSUs and the outcome of the pre-established performance criteria, a recipient may ultimately earn the target number of PSUs granted or a specified multiple thereof at the end of a 4–6 year vesting period, as applicable. As of December 31, 2024 and 2023, 1.4 million PSUs were unvested with a weighted-average grant date fair value of $247.91 per unit. The number of unvested PSUs represents the maximum number of units that are eligible to be earned. During the year ended December 31, 2024, the Company did not grant new PSUs and no PSUs were vested, forfeited, or cancelled. For each of the years ended December 31, 2024, 2023, and 2022 the Company recognized $52.1 million of stock-based compensation expense related to PSUs. As of December 31, 2024, there was $52.0 million of stock-based compensation cost related to unvested PSUs which had not yet been recognized. The Company expects to recognize this compensation cost on a straight-line basis over a weighted average period of 1.0 year. Fair Value Assumptions: The following table summarizes the weighted average values of the assumptions used in computing the fair value of PSUs that were granted during 2022. The Company did not grant PSUs during 2024 and 2023. 2022 Expected volatility 32% Expected dividend yield 0% Risk-free interest rate 3.3%

Employee Savings Plans

Employee Savings Plans	12 Months Ended
	Dec. 31, 2024
Retirement Benefits [Abstract]
Employee Savings Plans	Employee Savings Plans The Company maintains the Regeneron Pharmaceuticals, Inc. 401(k) Savings Plan, as amended and restated (the "Savings Plan"). The terms of the Savings Plan allow U.S. employees (as defined by the Savings Plan) to contribute to the Savings Plan a percentage of their compensation. In addition, the Company may make discretionary contributions, as defined, to the accounts of participants under the Savings Plan. The Company also maintains additional employee savings plans outside the United States, which cover eligible employees. Expenses recognized by the Company related to contributions to such plans were $90.2 million, $84.7 million, and $67.6 million for the years ended December 31, 2024, 2023, and 2022, respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Company is subject to U.S. federal, state, and foreign income taxes. Components of income before income taxes consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 United States $ (411.3) $ (362.3) $ 839.9 Foreign 5,191.2 4,561.6 4,018.9 $ 4,779.9 $ 4,199.3 $ 4,858.8 Components of income tax expense consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Current: Federal $ 1,092.6 $ 667.9 $ 968.5 State (11.1) 7.7 7.4 Foreign 43.1 407.9 290.9 Total current tax expense 1,124.6 1,083.5 1,266.8 Deferred: Federal (935.5) (834.5) (797.7) State (4.9) (6.5) (2.7) Foreign 183.1 3.2 54.0 Total deferred tax benefit (757.3) (837.8) (746.4) $ 367.3 $ 245.7 $ 520.4 A reconciliation of the U.S. statutory income tax rate to the Company's effective income tax rate is as follows: Year Ended December 31, 2024 2023 2022 U.S. federal statutory tax rate 21.0 % 21.0 % 21.0 % Stock-based compensation (4.9) (4.6) (2.9) Taxation of non-U.S. operations (4.0) (6.6) (5.5) Income tax credits (3.5) (3.2) (2.0) Foreign-derived intangible income deduction (0.8) (0.3) (1.0) Other permanent differences (0.1) (0.4) 1.1 Effective income tax rate 7.7 % 5.9 % 10.7 % Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company's deferred tax assets and liabilities are as follows: As of December 31, (In millions) 2024 2023 Deferred tax assets: Capitalized research and development expenses $ 2,530.2 $ 1,728.2 Deferred compensation 419.7 413.6 Accrued expenses 185.0 214.1 Fixed assets and intangible assets 145.1 154.8 Tax attribute carryforwards 84.1 88.7 Other 43.0 26.4 Total deferred tax assets 3,407.1 2,625.8 Deferred tax liabilities: Unrealized gains on investments (93.0) (50.4) Net deferred tax assets $ 3,314.1 $ 2,575.4 The Company's federal income tax returns for 2017 through 2023 remain open to examination by the IRS. The Company's 2017 and 2018 federal income tax returns are currently under audit by the IRS. In general, the Company's state income tax returns from 2020 to 2023 remain open to examination. The Company's income tax returns outside the United States remain open to examination from 2019 to 2023. The United States and many states generally have statutes of limitation ranging from 3 to 5 years; however, those statutes could be extended due to the Company's tax credit carryforward position. In general, tax authorities have the ability to review income tax returns in which the statute of limitation has previously expired to adjust the tax credits generated in those years. The following table reconciles the beginning and ending amounts of unrecognized tax benefits: (In millions) 2024 2023 2022 Balance as of January 1 $ 696.4 $ 542.8 $ 410.9 Gross increases related to current year tax positions 353.5 153.4 136.9 Gross increases (decreases) related to prior year tax positions 264.8 3.2 (5.0) Gross decreases due to settlements and lapse of statutes of limitations (1.0) (3.0) — Balance as of December 31 $ 1,313.7 $ 696.4 $ 542.8 In 2024, 2023, and 2022, the increases in unrecognized tax benefits primarily related to the Company's calculation of certain tax credits and other items related to the Company's international operations. Interest expense related to unrecognized tax benefits was $165.4 million, $77.2 million, and $38.0 million in 2024, 2023, and 2022, respectively. The Company expects the IRS to conclude its examination of the Company's 2017 and 2018 federal income tax returns within the next twelve months, and, as a result, the Company may be required to make a payment of approximately $120 million. The Company's unrecognized tax benefits for the years under examination exceed the expected payment amount, which would result in the Company recognizing a net tax benefit within the next twelve months.

Legal Matters

Legal Matters	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Legal Matters	Legal Matters From time to time, the Company is a party to legal proceedings in the course of the Company's business. The outcome of any such proceedings, regardless of the merits, is inherently uncertain. If the Company is unable to prevail in one or more of such proceedings, its consolidated financial position, results of operations, and future cash flows may be materially adversely impacted. Costs associated with the Company's involvement in legal proceedings are expensed as incurred. The Company recognizes accruals for loss contingencies associated with such proceedings when it is probable that a liability will be incurred and the amount of loss can be reasonably estimated. As of December 31, 2024 and 2023, the Company's accruals for loss contingencies were not material. There are certain loss contingencies that the Company deems reasonably possible for which the possible loss or range of possible loss is not estimable at this time. Proceedings Relating to EYLEA (aflibercept) Injection Certain of the Company's patents pertaining to EYLEA are subject to post-grant proceedings before the United States Patent and Trademark Office ("USPTO"), the European Patent Office (the "EPO"), or other comparable foreign authorities, including those described in greater detail below. In addition, the Company has filed patent infringement lawsuits in several jurisdictions alleging infringement of certain Company patents pertaining to EYLEA, including those described in greater detail below. United States U.S. Patent Litigation On August 2, 2022, the Company filed a patent infringement lawsuit against Mylan, a wholly-owned subsidiary of Viatris Inc., in the United States District Court for the Northern District of West Virginia alleging that Mylan's filing for U.S. Food and Drug Administration ("FDA") approval of an aflibercept 2 mg biosimilar infringes certain Company patents. On June 5, 2023, Biocon, as successor-in-interest to the aflibercept 2 mg biosimilar, was joined as a defendant to the lawsuit. A trial was held from June 12, 2023 through June 23, 2023 concerning certain claims of the '601 Patent, the '572 Patent, and the Company's U.S. Patent No. 11,084,865 (the "'865 Patent"). On December 27, 2023, the court issued a decision finding that (i) the asserted claims of the '865 Patent were valid and infringed by Mylan and Biocon and (ii) the asserted claims of the '601 and '572 Patents were infringed by Mylan and Biocon but were invalid as obvious. On June 11, 2024, the court granted the Company's motion for a permanent injunction, enjoining Mylan and Biocon from selling in the United States their aflibercept 2 mg biosimilar until the expiration of the '865 Patent. On June 21, 2024, Mylan and Biocon filed a notice of appeal of the court's December 27, 2023 and June 11, 2024 decisions to the Federal Circuit. An oral hearing concerning Mylan and Biocon's appeal has been scheduled for February 7, 2025. On November 8, November 22, and November 29, 2023, respectively, the Company filed patent infringement lawsuits against Celltrion, Samsung Bioepis, and Formycon AG in the United States District Court for the Northern District of West Virginia following service on Regeneron of each company's notice of commercial marketing. The lawsuits allege that each company has infringed certain Company patents, including based on each company's filing for FDA approval of an aflibercept 2 mg biosimilar. On December 27, 2023, the Company filed a second patent infringement lawsuit against Samsung Bioepis in the United States District Court for the Northern District of West Virginia alleging that Samsung's filing for FDA approval of an aflibercept 2 mg biosimilar infringes certain Company patents. On June 14, June 21, and June 28, 2024, respectively, the court granted the Company's motions for preliminary injunctions against Samsung Bioepis, Formycon, and Celltrion. On June 14, June 25, and July 8, 2024, respectively, Samsung Bioepis, Formycon, and Celltrion filed notices of appeal of the court's preliminary injunction decisions to the Federal Circuit. An oral hearing concerning the respective appeals of Samsung Bioepis and Formycon was held on December 5, 2024. On January 29, 2025, the Federal Circuit affirmed the lower court's preliminary injunction decisions against Samsung Bioepis and Formycon. An oral hearing concerning Celltrion's appeal has been scheduled for February 7, 2025. On January 10, 2024, the Company filed a patent infringement lawsuit against Amgen in the United States District Court for the Central District of California alleging that Amgen's filing for FDA approval of an aflibercept 2 mg biosimilar infringes certain Company patents. On April 11, 2024, the United States Judicial Panel on Multidistrict Litigation granted the Company's motion to transfer this lawsuit to the United States District Court for the Northern District of West Virginia for coordinated and consolidated pretrial proceedings with the lawsuits described in the preceding paragraph. On June 7, 2024, the Company filed a motion for a preliminary injunction against Amgen. On September 23, 2024, the court denied the Company's motion for a preliminary injunction, and the Company filed (i) a notice of appeal of such decision to the Federal Circuit, (ii) a motion for an immediate administrative stay, and (iii) a motion for a temporary injunction preventing Amgen from launching its aflibercept 2 mg biosimilar during the pendency of such appeal. On September 25, 2024, the Federal Circuit issued an administrative stay pending its review of the Company's temporary injunction motion. On October 22, 2024, the Federal Circuit denied the Company's temporary injunction motion and lifted the administrative stay. An expedited oral hearing concerning the Company's appeal of the court's preliminary injunction decision was held on January 14, 2025. On August 26, 2024, the Company filed a patent infringement lawsuit against Sandoz Inc. in the United States District Court for the District of New Jersey alleging that Sandoz's filing for FDA approval of an aflibercept 2 mg biosimilar infringes certain Company patents. On September 12, 2024, the United States Judicial Panel on Multidistrict Litigation granted the Company's motion to transfer this lawsuit to the United States District Court for the Northern District of West Virginia for coordinated and consolidated pretrial proceedings with the lawsuits described in the preceding paragraphs. Post-Grant Proceedings Before the USPTO On November 20, 2024, November 29, 2024, and January 15, 2025, Samsung Bioepis Co., Ltd., Formycon AG, and Celltrion Inc., respectively, filed inter partes review ("IPR") petitions in the USPTO against the Company's U.S. Patent No. 11,084,865 (the "'865 Patent"), each seeking a declaration that the '865 Patent is invalid. Europe EPO Post-Grant Proceedings Various parties, including Amgen and other anonymous parties, are seeking revocation of the Company's European Patent Nos. 2,944,306 (the "'306 Patent"), 3,716,992 (the "'992 Patent"), and 3,384,049 (the "'049 Patent") before the Opposition Division of the EPO. On November 26, 2024, following an oral hearing, the Opposition Division ("OD") of the EPO announced its decision to revoke the '306 Patent. The Company plans to appeal the OD's decision. Oral proceedings concerning the '992 Patent are scheduled for October 2025. Country-Specific Proceedings Various parties, including Amgen, Samsung Bioepis, and Formycon and/or their affiliated entities, are seeking revocation of the '306 Patent, the '992 Patent, and the Company's European Patent No. 2,364,691 (the "'691 Patent") and/or a declaration that its aflibercept 2 mg biosimilar would not infringe these patents in several European national courts (including those in France, Germany, Italy, the Netherlands, and the United Kingdom). In the United Kingdom, the Company has filed a preemptive counterclaim against Formycon AG and Klinge Biopharma GmbH, Samsung Bioepis UK Limited, and Amgen Inc. for infringement of the '306 Patent and the '691 Patent. In Germany, a trial concerning the '691 Patent has been scheduled to begin in June 2025. In the United Kingdom, trials concerning the '691 and '306 Patents have been scheduled to begin in June 2025, and the '992 Patent proceedings are stayed pending resolution of the EPO proceedings concerning this patent. In the Netherlands, a trial concerning the '691 and '306 Patents has been scheduled to begin in July 2025. The Company has commenced proceedings in Belgium against various parties, including Amgen Inc., Celltrion Inc., Sterigenics (Petit-Rechain) NV, and Sandoz GmbH, for infringement of the Company's European Patent No. 1,183,353 (as extended by Supplementary Protection Certificate 2013C/029). Canada Proceedings against Amgen Canada On May 9, 2023, Amgen Canada Inc. ("Amgen Canada") filed invalidation proceedings against the Company in the Federal Court of Canada seeking revocation of the Company's Canadian Patent Nos. 2,654,510 (the "'510 Patent") and 3,007,276 (the "'276 Patent"). On September 14, 2023, the Company, Bayer Inc., and Bayer Healthcare LLC filed patent infringement lawsuits against Amgen Canada in the Federal Court of Canada seeking a declaration that the making, constructing, using, or selling of an aflibercept 2 mg biosimilar would directly or indirectly infringe one or more claims of Bayer Healthcare LLC's Canadian Patent No. 2,970,315 (the "'315 Patent"). On September 14, 2023, the Company and Bayer Inc. filed three separate patent infringement lawsuits against Amgen Canada in the Federal Court of Canada seeking a declaration that the making, constructing, using, or selling of an aflibercept 2 mg biosimilar would directly or indirectly infringe one or more claims of the Company's Canadian Patent Nos. 3,129,193 (the "'193 Patent"), 2,965,495 (the "'495 Patent"), and 2,906,768 (the "'768 Patent"), respectively. On October 11, 2023, the Company, Bayer Inc., and Bayer Healthcare LLC filed two separate patent infringement lawsuits against Amgen Canada in the Federal Court of Canada seeking a declaration that the making, constructing, using, or selling of an aflibercept 2 mg biosimilar would directly or indirectly infringe one or more claims of the Company's '510 Patent and '276 Patent, respectively. On May 7, 2024 and June 28, 2024, respectively, Amgen filed a summary trial motion with respect to the '510 Patent and a motion to delist the '276 Patent from the Canada Patent Register. On November 20, 2024, the court granted Amgen's motion to delist the '276 Patent from the Canada Patent Register, which decision has been appealed by the Company and Bayer. A trial for the lawsuits concerning the '510 Patent and the '276 Patent has been scheduled for May–June 2025; and a trial for the lawsuits concerning the '315 Patent and the '193 Patent has been scheduled for August–September 2025. Proceedings against Sandoz On January 24, 2025, the Company, Bayer Inc., and Bayer Healthcare LLC filed patent infringement lawsuits against Sandoz Canada Inc. in the Federal Court of Canada seeking a declaration that the making, constructing, using, or selling of an aflibercept 2 mg biosimilar would directly or indirectly infringe one or more claims of the '510 Patent, the '276 Patent, the '495 Patent, the '768 Patent, the '193 Patent, the '315 Patent, and Canadian Patent No. 3,137,326 (the "'326 Patent"). South Korea On October 31, 2022 and December 13, 2022, Samsung Bioepis Co., Ltd. initiated invalidation proceedings before the Intellectual Property Trial and Appeal Board of the Korean Intellectual Property Office ("KIPO") against the Company's Korean Patent Nos. 1131429 (the "'429 Patent") and 1406811 (the "'811 Patent"), respectively, seeking revocation of each such patent in its entirety. On October 23, 2024, the KIPO maintained the '811 Patent as valid, and Samsung appealed this decision on November 6, 2024. On November 20, 2024, the KIPO maintained the '429 Patent as valid in an amended form that no longer contains claims to aflibercept. The Company and, as applicable, Bayer Consumer Care AG, have also filed patent infringement lawsuits in the Seoul Central District Court against various parties including Samsung Bioepis Co., Ltd. and its parent company Samsung Biologics Co., Ltd., Sam Chun Dang Pharm. Co., Ltd. and OPTUS Pharmaceutical Co., Ltd, and Celltrion Inc. These lawsuits seek damages and/or injunctive relief and allege that the making, constructing, using, or selling of an aflibercept 2 mg biosimilar by the relevant defendant(s) would infringe one or more claims of the '811 Patent and/or the Company's Korean Patent Nos. 659477 (the "'477 Patent") and 2519234 (the "'234 Patent"). Proceedings Relating to EYLEA (aflibercept) Injection Pre-filled Syringe On June 19, 2020, Novartis Pharma AG, Novartis Pharmaceuticals Corporation, and Novartis Technology LLC (collectively, "Novartis") filed a patent infringement lawsuit (as amended on August 2, 2021) in the U.S. District Court for the Northern District of New York asserting claims of Novartis's U.S. Patent No. 9,220,631 (the "'631 Patent"). On November 13, 2024, this lawsuit was dismissed in light of the final resolution of the IPR proceeding discussed below. On July 16, 2020, the Company initiated two IPR petitions in the USPTO seeking a declaration that the '631 Patent is invalid on two separate grounds. On October 25, 2022, the Patent Trial and Appeal Board ("PTAB") of the USPTO issued a final written decision invalidating all claims of the '631 Patent; and on September 23, 2024, the Federal Circuit affirmed the PTAB's decision invalidating all claims of the '631 Patent. On July 17, 2020, the Company filed an antitrust lawsuit against Novartis and Vetter Pharma International Gmbh ("Vetter") in the United States District Court for the Southern District of New York seeking a declaration that the '631 Patent is unenforceable and a judgment that the defendants' conduct violates Sections 1 and 2 of the Sherman Antitrust Act of 1890, as amended (the "Sherman Antitrust Act"). The Company is also seeking injunctive relief and treble damages. On September 21, 2021, this lawsuit was transferred to the Northern District of New York. On June 10, 2022, the Company filed an appeal of the District Court's decision to dismiss the amended complaint with the U.S. Court of Appeals for the Second Circuit (the "Second Circuit"). On March 18, 2024, the Second Circuit reversed the District Court's decision to dismiss the amended complaint and remanded the lawsuit to the District Court for further proceedings consistent with the Second Circuit's opinion. On November 19, 2024, the Company moved to transfer the lawsuit back to the Southern District of New York, which motion was granted on December 5, 2024. Proceedings Relating to Praluent (alirocumab) Injection United States On May 27, 2022, the Company filed a lawsuit against Amgen Inc. in the United States District Court for the District of Delaware, alleging that, beginning in 2020, Amgen engaged in an anticompetitive bundling scheme which was designed to exclude Praluent from the market in violation of federal and state laws. The lawsuit seeks damages for harm caused by the alleged scheme, as well as injunctive relief restraining Amgen from continuing its alleged anticompetitive conduct. On August 1 and 11, 2022, Amgen filed a motion to dismiss the complaint and a motion to stay these proceedings, respectively. On February 10, 2023, the court denied Amgen's motion to stay; and on March 21, 2023, the court denied Amgen's motion to dismiss. On August 28, 2023, the Company filed an amended complaint in this matter; and, as part of its response, on September 20, 2023, Amgen filed a counterclaim alleging that the Company engaged in unfair business practices in violation of state law. On May 22, 2024, Amgen filed a motion for summary judgment. An oral hearing on Amgen's motion for summary judgment was held on November 20, 2024. A trial has been scheduled to begin in May 2025. Europe On June 1, 2023, Sanofi filed an action in the Munich Central Division of the Unified Patent Court (the "UPC") seeking revocation of Amgen's European Patent No. 3,666,797 (the "'797 Patent"). The '797 Patent is a divisional patent of European Patent No. 2,215,124 (the "'124 Patent") (i.e., a patent that shares the same priority date, disclosure, and patent term of the parent '124 Patent), which was previously invalidated by the Technical Board of Appeal of the EPO. On July 16, 2024, following a trial, the Munich Central Division of the UPC issued a decision revoking the '797 Patent in its entirety. On September 16, 2024, Amgen appealed the decision of the Munich Central Division of the UPC to the Court of Appeal of the UPC. An oral hearing before the Court of Appeal of the UPC has been scheduled for May 2025. Also on June 1, 2023, Amgen filed a lawsuit against the Company and certain of Sanofi's affiliated entities in the Munich Local Division of the UPC alleging infringement of the '797 Patent. The lawsuit seeks, among other things, a permanent injunction in several countries in Europe and monetary damages. On July 29, 2024, the Munich Local Division of the UPC ordered a stay of the infringement lawsuit in light of the decision of the Munich Central Division of the UPC to revoke the '797 Patent in its entirety (discussed above). Proceedings Relating to REGEN-COV (casirivimab and imdevimab) On October 5, 2020, Allele Biotechnology and Pharmaceuticals, Inc. ("Allele") filed a lawsuit (as amended on April 8, 2021 and December 12, 2022) against the Company in the United States District Court for the Southern District of New York, asserting infringement of U.S. Patent No. 10,221,221. Effective December 5, 2024, the parties entered into a settlement agreement, pursuant to which this lawsuit has been dismissed. Department of Justice Matters In January 2017, the Company received a subpoena from the U.S. Attorney's Office for the District of Massachusetts requesting documents relating to its support of 501(c)(3) organizations that provide financial assistance to patients; documents concerning its provision of financial assistance to patients with respect to products sold or developed by Regeneron (including EYLEA, Praluent, ARCALYST ® , and ZALTRAP ® ); and certain other related documents and communications. On June 24, 2020, the U.S. Attorney's Office for the District of Massachusetts filed a civil complaint in the U.S. District Court for the District of Massachusetts alleging violations of the federal Anti-Kickback Statute, and asserting causes of action under the federal False Claims Act and state law (the "June 2020 Civil Complaint"). On August 24, 2020, the Company filed a motion to dismiss the June 2020 Civil Complaint in its entirety. On December 4, 2020, the court denied the motion to dismiss. On December 28, 2022, the U.S. Attorney's Office for the District of Massachusetts filed a motion for partial summary judgment. On January 31, 2023, the Company filed a motion for summary judgment. An oral hearing on the parties' respective motions for summary judgment was held on July 21, 2023. On September 27, 2023, the court (i) denied in part and granted in part the Company's motion for summary judgment and (ii) denied in its entirety the motion for partial summary judgment filed by the U.S. Attorney's Office for the District of Massachusetts. On October 25, 2023, the court certified for interlocutory appeal a portion of the court's September 27, 2023 order that addressed the causation standard applicable to the alleged violations of the federal Anti-Kickback Statute and federal False Claims Act; and on December 11, 2023, the U.S. Court of Appeals for the First Circuit certified for appeal (i.e., accepted for review) the court's September 27, 2023 order. An oral hearing concerning the appeal to the U.S. Court of Appeals for the First Circuit was held on July 22, 2024. In September 2019, the Company and Regeneron Healthcare Solutions, Inc., a wholly-owned subsidiary of the Company, each received a civil investigative demand ("CID") from the U.S. Department of Justice pursuant to the federal False Claims Act relating to remuneration paid to physicians in the form of consulting fees, advisory boards, speaker fees, and payment or reimbursement for travel and entertainment allegedly in violation of the federal Anti-Kickback Statute. The CIDs relate to EYLEA, Praluent, Dupixent, ZALTRAP, ARCALYST, and Kevzara and cover the period from January 2015 to the present. On June 3, 2021, the United States District Court for the Central District of California unsealed a qui tam complaint filed against the Company, Regeneron Healthcare Solutions, Inc., and Sanofi-Aventis U.S. LLC by two qui tam plaintiffs (known as relators) purportedly on behalf of the United States and various states (the "State Plaintiffs"), asserting causes of action under the federal False Claims Act and state law. Also on June 3, 2021, the United States and the State Plaintiffs notified the court of their decision to decline to intervene in the case. On October 29, 2021, the qui tam plaintiffs filed an amended complaint in this matter. On January 14, 2022, the Company filed a motion to dismiss the amended complaint in its entirety. On July 25, 2023, the court granted in part and denied in part the Company's motion to dismiss. On September 1, 2023, the Company filed a second motion to dismiss the amended complaint or, in the alternative, a motion for judgment on the pleadings. On July 31, 2024 and August 15, 2024, respectively, the District Court granted the Company's second motion to dismiss the amended complaint with respect to the remaining causes of action under federal law and declined to exercise supplemental jurisdiction over the remaining causes of action under state law. On August 26, 2024, the qui tam plaintiffs filed a notice of appeal. In June 2021, the Company received a CID from the U.S. Department of Justice pursuant to the federal False Claims Act. The CID states that the investigation concerns allegations that the Company (i) violated the False Claims Act by paying kickbacks to distributors and ophthalmology practices to induce purchase of EYLEA, including through discounts, rebates, credit card fees, free units of EYLEA, and inventory management systems; and (ii) inflated reimbursement rates for EYLEA by excluding applicable discounts, rebates, and benefits from the average sales price reported to the Centers for Medicare & Medicaid Services. The CID covers the period from January 2011 through June 2021. On November 29, 2023, the U.S. Department of Justice informed the Company that it had filed a notice of partial intervention in this matter. On March 28, 2024, the Department of Justice and the U.S. Attorney's Office for the District of Massachusetts filed a civil complaint intervention (the "March 2024 Civil Complaint") in the U.S. District Court for the District of Massachusetts asserting causes of action under the federal False Claims Act and a claim for unjust enrichment. Also on March 28, 2024, the U.S. District Court of the District of Massachusetts unsealed a qui tam complaint against the Company, AmerisourceBergen, and Besse Medical by two qui tam plaintiffs (known as relators) purportedly on behalf of the United States and various states and municipalities, asserting causes of action under the federal False Claims Act and state and local laws, and alleging violations of the federal Anti-Kickback statute. On June 25, 2024, the States of Colorado, Georgia, Michigan, North Carolina, Texas, and Washington filed a civil complaint in partial intervention (the "June 2024 Civil Complaint") in the U.S. District Court for the District of Massachusetts asserting causes of action under various state laws. On July 18, 2024, the Company filed a motion to dismiss the March 2024 Civil Complaint and the June 2024 Civil Complaint. An oral hearing on the Company's motion to dismiss was held on December 16, 2024. Proceedings Initiated by Other Payors The Company is party to several lawsuits relating to the conduct alleged in the June 2020 Civil Complaint discussed under "Department of Justice Matters" above. These lawsuits were filed by UnitedHealthcare Insurance Company and United Healthcare Services, Inc. (collectively, "UHC") and Humana Inc. ("Humana") in the United States District Court for the Southern District of New York on December 17, 2020 and July 22, 2021, respectively; and by Blue Cross and Blue Shield of Massachusetts, Inc. and Blue Cross and Blue Shield of Massachusetts HMO Blue, Inc. (collectively, "BCBS"), Medical Mutual of Ohio ("MMO"), Horizon Healthcare Services, Inc. d/b/a Horizon Blue Cross Blue Shield of New Jersey ("Horizon"), and Local 464A United Food and Commercial Workers Union Welfare Service Benefit Fund ("Local 464A") in the U.S. District Court for the District of Massachusetts on December 20, 2021, February 23, 2022, April 4, 2022, and June 17, 2022, respectively. These lawsuits allege causes of action under state law and the federal Racketeer Influenced and Corrupt Organizations Act ("RICO") and seek monetary damages and equitable relief. The MMO and Local 464A lawsuits are putative class action lawsuits. On December 29, 2021, the lawsuits filed by UHC and Humana were stayed by the United States District Court for the Southern District of New York pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts concerning the allegations in the June 2020 Civil Complaint. On September 27, 2022, the lawsuits filed by BCBS, MMO, and Horizon were stayed by the U.S. District Court for the District of Massachusetts pending resolution of the proceedings before the same court concerning the allegations in the June 2020 Civil Complaint; and, in light of these stays, the parties to the Local 464A action have also agreed to stay that matter. On June 24, 2024, a group of plaintiffs purporting to be assignees of claims by various Medicare Advantage plans and related entities filed a putative class action complaint in the U.S. District Court for the District of Columbia on behalf of Medicare Advantage plans and other payors. The lawsuit relates to the conduct alleged in the June 2020 Civil Complaint, March 2024 Civil Complaint, and June 2024 Civil Complaint discussed under "Department of Justice Matters" above. The lawsuit alleges causes of action under state law and RICO and seeks monetary damages and equitable relief. On October 22, 2024, the Company filed a motion to transfer the proceedings to the U.S. District Court for the District of Massachusetts or, in the alternative, to stay the proceedings or dismiss the proceedings. On January 28, 2025, pursuant to a stipulation among the parties, the proceedings were transferred to the U.S. District Court for the District of Massachusetts. 2021 Shareholder Derivative Complaint On June 29, 2021, an alleged shareholder filed a shareholder derivative complaint in the New York Supreme Court, naming the then-current and certain former members of the Company's board of directors and certain then-current and former executive officers of the Company as defendants and Regeneron as a nominal defendant. The complaint asserts that the individual defendants breached their fiduciary duties in relation to the allegations in the June 2020 Civil Complaint discussed under "Department of Justice Matters" above. The complaint seeks an award of damages allegedly sustained by the Company; an order requiring Regeneron to take all necessary actions to reform and improve its corporate governance and internal procedures; disgorgement from the individual defendants of all profits and benefits obtained by them resulting from their sales of Regeneron stock; and costs and disbursements of the action, including attorneys' fees. On July 28, 2021, the defendants filed a notice of removal, removing the case from the New York Supreme Court to the U.S. District Court for the Southern District of New York. On September 23, 2021, the plaintiff moved to remand the case to the New York Supreme Court. Also on September 23, 2021, the individual defendants moved to dismiss the complaint in its entirety. On December 19, 2022, the U.S. District Court for the Southern District of New York denied the plaintiff's motion to remand the case and granted a motion to stay the case pending resolution of the proceedings before the U.S. District Court for the District of Massachusetts concerning the allegations in the June 2020 Civil Complaint. As a result of the stay, the court also terminated the Company's motion to dismiss the complaint without prejudice. The Company can therefore renew the motion to dismiss upon conclusion of the stay. Class Action Civil Complaint On January 7, 2025, a purported shareholder filed a putative class action civil complaint, on behalf of himself and all others similarly situated, in the U.S. District Court for the Southern District of New York against the Company and certain current and former executive officers of the Company. The complaint asserts violations of federal securities laws in connection with statements or disclosures purportedly related to the conduct alleged in the March 2024 Civil Complaint discussed under "Department of Justice Matters" above. 2025 Shareholder Derivative Complaints On January 16 and January 22, 2025, purported shareholders filed two separate shareholder derivative complaints in the U.S. District Court for the Southern District of New York against members of the Company's board of directors and certain current and former executive officers of the Company as defendants and Regeneron as a nominal defendant. The complaints each allege that the individual defendants, among other things, breached their fiduciary duties to the Company by failing to properly manage and oversee the Company in connection with the conduct alleged in the March 2024 Civil Complaint discussed under "Department of Justice Matters" above. The complaints also each allege that the individual defendants breached the federal securities laws, wasted corporate assets, and unjustly enriched themselves at the expense of the Company. The complaints each seek, among other things, an award of damages allegedly sustained by the Company as a result of the alleged misconduct of the individual defendants; an order requiring the individual defendants to take all necessary actions to reform and improve the Company’s corporate governance and internal procedures; and costs and disbursements of the applicable action, including attorneys' fees. Sanofi Litigation On November 18, 2024, the Company filed a lawsuit (as amended on December 20, 2024) in the United States District Court for the Southern District of New York against Sanofi and certain of its affiliated entities. The lawsuit alleges that the defendants breached certain provisions of the parties' Amended and Restated License and Collaboration Agreement, dated as of November 10, 2009 (as amended, the "Collaboration Agreement"), concerning Sanofi's obligation to provide Regeneron with full access to material information relating to the commercialization of Dupixent or other products commercialized pursuant to the Collaboration Agreement and Regeneron's audit rights under the Collaboration Agreement. The lawsuit seeks a declaratory judgment, injunctive relief, damages, and other relief.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Net Income Per Share	Net Income Per Share The calculations of basic and diluted net income per share are as follows: Year Ended December 31, (In millions, except per share data) 2024 2023 2022 Net income - basic and diluted $ 4,412.6 $ 3,953.6 $ 4,338.4 Weighted average shares - basic 107.9 106.7 107.1 Effect of dilutive securities: Stock options 4.8 4.9 4.9 Restricted stock awards and restricted stock units 2.4 2.1 1.5 Weighted average shares - diluted 115.1 113.7 113.5 Net income per share - basic $ 40.90 $ 37.05 $ 40.51 Net income per share - diluted $ 38.34 $ 34.77 $ 38.22 Shares which have been excluded from diluted per share amounts because their effect would have been antidilutive include the following: Year Ended December 31, (Shares in millions) 2024 2023 2022 Stock options 1.6 1.8 2.3

Statement of Cash Flows

Statement of Cash Flows	12 Months Ended
	Dec. 31, 2024
Cash and Cash Equivalents [Abstract]
Statement of Cash Flows	Statement of Cash Flows The following provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets to the total of the same such amounts shown in the Consolidated Statements of Cash Flows: December 31, (In millions) 2024 2023 2022 Cash and cash equivalents $ 2,488.2 $ 2,730.0 $ 3,105.9 Restricted cash included in Other current assets 0.8 — — Restricted cash included in Other noncurrent assets — 7.8 13.5 Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 2,489.0 $ 2,737.8 $ 3,119.4 Restricted cash consists of amounts held by financial institutions pursuant to contractual arrangements. Supplemental disclosure of non-cash investing and financing activities As of December 31, (In millions) 2024 2023 2022 Accrued capital expenditures $ 151.6 $ 75.4 $ 70.8 Accrued contingent consideration in connection with acquisitions $ 62.7 $ 71.6 $ 135.5

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net income	$ 4,412.6	$ 3,953.6	$ 4,338.4

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended	12 Months Ended
	Dec. 31, 2024 shares	Dec. 31, 2024 shares
Trading Arrangements, by Individual
Material Terms of Trading Arrangement		As disclosed in the table below, during the three months ended December 31, 2024, certain of our directors and/or executive officers adopted plans for trading arrangements intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) of the Exchange Act. Name Position Date of Plan Adoption Scheduled End Date of Trading Arrangement (a) Total Number of Securities to Be Sold Under the Plan Kathryn Guarini, Ph.D. Director 11/1/2024 11/14/2025 1,000 (a) The trading arrangement may expire on an earlier date if and when all transactions under the arrangement are completed.
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false
Kathryn Guarini, Ph.D. [Member]
Trading Arrangements, by Individual
Name	Kathryn Guarini, Ph.D.
Title	Director
Rule 10b5-1 Arrangement Adopted	true
Adoption Date	11/1/2024
Expiration Date	11/14/2025
Arrangement Duration	378 days
Aggregate Available	1,000	1,000

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Cybersecurity Risk Management a

Cybersecurity Risk Management and Strategy Disclosure	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	We regularly assess risks from cybersecurity threats; monitor our information systems for potential vulnerabilities; and test those systems pursuant to our cybersecurity policies, processes, and practices, which are integrated into our overall risk management program. To protect our information systems from cybersecurity threats, we use various security tools that are designed to help identify, escalate, investigate, resolve, and recover from security incidents in a timely manner. Our Technology Risk Management Committee, which is comprised of representatives from our business operations and support functions (e.g., legal, finance, internal audit, commercial, privacy), assesses cybersecurity risks based on probability and potential impact to key business systems and processes. Cybersecurity risks that are considered high are incorporated into our overall risk management program. A mitigation plan is developed for each identified high risk, with progress on risk mitigation reported to the Technology Risk Management Committee and tracked as part of our overall risk management program, which is overseen by the Audit Committee of our board of directors. We collaborate with third parties to assess the effectiveness of our cybersecurity prevention and response systems and processes. These include cybersecurity assessors, consultants, and other external cybersecurity experts to assist in the identification, verification, and validation of cybersecurity risks, as well as to support associated mitigation plans when necessary. We have also developed a process to conduct due diligence on third parties with which we work to oversee and identify material risks from cybersecurity threats associated with our use of those third parties' services, including those that perform cybersecurity services. To date, the Company is not aware of risks from cybersecurity threats, including those resulting from any previous cybersecurity incidents, that have materially affected or are reasonably likely to materially affect our Company, including our business strategy, results of operations, or financial condition. Refer to the risk factor captioned " Significant disruptions of information technology systems or breaches of data security could adversely affect our business " in Part I, Item 1A. "Risk Factors" for additional information regarding cybersecurity risks and potential related impacts on our Company.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	We regularly assess risks from cybersecurity threats; monitor our information systems for potential vulnerabilities; and test those systems pursuant to our cybersecurity policies, processes, and practices, which are integrated into our overall risk management program. To protect our information systems from cybersecurity threats, we use various security tools that are designed to help identify, escalate, investigate, resolve, and recover from security incidents in a timely manner. Our Technology Risk Management Committee, which is comprised of representatives from our business operations and support functions (e.g., legal, finance, internal audit, commercial, privacy), assesses cybersecurity risks based on probability and potential impact to key business systems and processes. Cybersecurity risks that are considered high are incorporated into our overall risk management program. A mitigation plan is developed for each identified high risk, with progress on risk mitigation reported to the Technology Risk Management Committee and tracked as part of our overall risk management program, which is overseen by the Audit Committee of our board of directors.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	false
Cybersecurity Risk Board of Directors Oversight [Text Block]	Our board of directors oversees our risk management process, including as it pertains to cybersecurity risks, directly and through its committees. The Audit Committee of the board oversees our risk management program, which focuses on the most significant risks we face in the short-, intermediate-, and long-term timeframe. Audit Committee meetings include discussions of specific risk areas throughout the year, including, among others, those relating to cybersecurity threats, and reports from the Chief Audit Executive on our enterprise risk profile on an annual basis. The Audit Committee reviews our cybersecurity risk profile with management on a periodic basis using key performance and/or risk indicators. These key performance indicators are metrics and measurements designed to assess the effectiveness of our cybersecurity program in the prevention, detection, mitigation, and remediation of cybersecurity incidents.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	Audit Committee
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	The CISO provides periodic updates on our cybersecurity risk profile to management's Technology Risk Management Committee and the Audit Committee of our board of directors.
Cybersecurity Risk Role of Management [Text Block]	We take a risk-based approach to cybersecurity and have implemented cybersecurity policies throughout our operations that are designed to address cybersecurity threats and incidents. The Company's Chief Information Security Officer ("CISO"), in coordination with the Chief Information Officer and the Technology Risk Management Committee, is responsible for the establishment and maintenance of our cybersecurity program, as well as the assessment and management of cybersecurity risks. The current CISO has over 35 years of experience in technology and information security, including operating in the role of the CISO for several large companies in the pharmaceutical and healthcare industries, and possesses the requisite education, skills, experience, and industry certifications expected of an individual assigned to these duties. The CISO provides periodic updates on our cybersecurity risk profile to management's Technology Risk Management Committee and the Audit Committee of our board of directors.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	The Company's Chief Information Security Officer ("CISO"), in coordination with the Chief Information Officer and the Technology Risk Management Committee, is responsible for the establishment and maintenance of our cybersecurity program, as well as the assessment and management of cybersecurity risks. The current CISO has over 35 years of experience in technology and information security, including operating in the role of the CISO for several large companies in the pharmaceutical and healthcare industries, and possesses the requisite education, skills, experience, and industry certifications expected of an individual assigned to these duties. The CISO provides periodic updates on our cybersecurity risk profile to management's Technology Risk Management Committee and the Audit Committee of our board of directors.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	The current CISO has over 35 years of experience in technology and information security, including operating in the role of the CISO for several large companies in the pharmaceutical and healthcare industries, and possesses the requisite education, skills, experience, and industry certifications expected of an individual assigned to these duties.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	The CISO provides periodic updates on our cybersecurity risk profile to management's Technology Risk Management Committee and the Audit Committee of our board of directors.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Business Overview and Summary_2

Business Overview and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements include the accounts of Regeneron and its wholly-owned subsidiaries. Intercompany balances and transactions are eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform with the current period's presentation.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially expose the Company to concentrations of credit risk consist of cash, cash equivalents, certain investments, and accounts receivable. In accordance with the Company's policies, the Company mandates asset diversification and monitors exposure with its counterparties.
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers all highly liquid debt instruments with a maturity of three months or less when purchased to be cash equivalents. The carrying amount reported in the Consolidated Balance Sheet for cash and cash equivalents approximates its fair value.
Debt and Equity Securities	Debt and Equity Securities The Company has an investment policy that includes guidelines on acceptable investment securities, minimum credit quality, maturity parameters, and diversification. The Company invests its cash primarily in debt securities. The Company considers its investments in debt securities to be "available-for-sale," as defined by authoritative guidance issued by the Financial Accounting Standards Board ("FASB"). These assets are carried at fair value and the unrealized gains and losses are included in accumulated other comprehensive income (loss). Realized gains and losses on available-for-sale debt securities are included in other income (expense), net. The Company reviews its portfolio of available-for-sale debt securities, using both quantitative and qualitative factors, to determine if declines in fair value below cost have resulted from a credit-related loss or other factors. If the decline in fair value is due to credit-related factors, a loss is recognized in net income, whereas if the decline in fair value is not due to credit-related factors, the loss is recorded in other comprehensive income (loss).
Accounts Receivable	Accounts Receivable
Inventories	Inventories Inventories are stated at the lower of cost or net realizable value. The Company determines the cost of inventory using the first-in, first-out, or FIFO, method. The Company capitalizes inventory costs associated with the Company's products prior to regulatory approval when, based on management's judgment, future commercialization is considered probable and future economic benefit is expected to be realized; otherwise, such costs are expensed. The determination to capitalize inventory costs is based on various factors, including status and expectations of the regulatory approval process, any known safety or efficacy concerns, potential labeling restrictions, and any other impediments to obtaining regulatory approval. The Company periodically analyzes its inventory levels to identify inventory that may expire prior to expected sale or has a cost basis in excess of its estimated realizable value. In addition, the Company's products are subject to strict quality control and monitoring which the Company performs throughout the manufacturing process. If certain batches or units of product no longer meet quality specifications or become obsolete due to expiration, the Company records a charge to write down such inventory to its estimated realizable value.
Property, Plant and Equipment	Property, Plant, and Equipment Property, plant, and equipment are stated at cost, net of accumulated depreciation. Depreciation is calculated on a straight-line basis over the estimated useful lives of the assets. Leasehold improvements are amortized over the shorter of the estimated useful lives of the assets or the remaining lease term. Costs of construction of certain long-lived assets include capitalized interest, which is amortized over the estimated useful life of the related asset. Expenditures for maintenance and repairs which do not materially extend the useful lives of the assets are charged to expense as incurred. The cost and accumulated depreciation or amortization of assets retired or sold are removed from the respective accounts, and any gain or loss is recognized within income from operations. The estimated useful lives of property, plant, and equipment are as follows: Building and improvements 10–50 years Laboratory and other equipment 3–10 years Furniture and fixtures 5 years
Leases	Leases The Company determines if an arrangement is a lease considering whether there is an identified asset and the contract conveys the right to control its use. Leases with an initial term of 12 months or less are not recorded on the balance sheet. The Company may include options to extend or terminate a lease within the lease term when it is reasonably certain that it will exercise that option. The Company accounts for lease components (e.g., rental payments) separately from non-lease components (e.g., common area maintenance costs). Lease liabilities are recognized at the lease commencement date based on the present value of the remaining lease payments, discounted using the rate implicit in the lease. For leases where an implicit rate is not readily determinable, the Company uses its incremental borrowing rate based on information available at the lease commencement date to determine the present value of future lease payments. Lease expense for operating leases is recognized on a straight-line basis over the expected lease term. The Company conducts certain of its research, development, and administrative activities at leased facilities. The Company also leases vehicles and other assets. Tarrytown, New York Corporate Headquarters The Company leases laboratory and office facilities for its corporate headquarters in Tarrytown, New York (the "Facility") under the Third Amended and Restated Lease and Remedies Agreement (the "Lease") with BA Leasing BSC, LLC, an affiliate of Banc of America Leasing & Capital, LLC ("BAL"), as lessor, and the Third Amended and Restated Participation Agreement (the "Participation Agreement") with Bank of America, N.A., as administrative agent, and a syndicate of lenders (collectively with BAL, the "Participants"), as rent assignees. The Lease, Participation Agreement, and certain related agreements provide for $720.0 million of lease financing (previously advanced by the Participants in March 2017 in connection with the acquisition by BAL of the Facility and the Company's lease of the Facility from BAL), which matures when the term of the Lease expires in March 2027, at which time all amounts outstanding thereunder will become payable in full. The Company has the option to further extend the maturity date of the Participation Agreement and the term of the Lease for an additional five-year period, subject to the consent of the Participants and certain other conditions. The Company also has the option to (a) purchase the Facility by paying an amount equal to the outstanding principal amount of the Participants' advances under the Participation Agreement, all accrued and unpaid yield thereon, and all other outstanding amounts under the Participation Agreement, Lease, and certain related documents or (b) sell the Facility to a third party on behalf of BAL. Pursuant to the Lease, the Company pays all maintenance, insurance, taxes, and other costs arising out of the use of the Facility. The Company is also required to make monthly payments of basic rent to satisfy the yield payable to the Participants on their outstanding advances under the Participation Agreement. Such advances accrue yield at a variable rate per annum based on the one-month forward-looking Secured Overnight Financing Rate ("SOFR") term rate, plus a spread adjustment, plus an applicable margin that varies with the Company's debt rating and total leverage ratio. The Lease is classified as a finance lease as the Company has the option to purchase the Facility under terms that make it reasonably certain to be exercised. The agreements governing the Lease financing contain financial and operating covenants. Such financial covenants and certain of the operating covenants are substantially similar to the covenants set forth in the Credit Agreement. The Company was in compliance with all such covenants as of December 31, 2024.
Acquisitions	Acquisitions The Company makes a determination whether a transaction should be accounted for as a business combination or as an asset acquisition. In a business combination, the acquisition method of accounting generally requires that the assets acquired and liabilities assumed be recorded as of the date of the acquisition at their respective fair values. Amounts allocated to acquired in-process research and development are capitalized as indefinite-lived intangible assets. Any excess of the purchase price (consideration transferred) over the fair values of net assets acquired is recorded as goodwill. Contingent consideration obligations are recorded at fair value as of the acquisition date and remeasured each subsequent reporting period until the contingencies have been resolved, with any changes in fair value recorded in Other operating (income) expense, net. If it is determined that the assets acquired do not meet the definition of a business, or if substantially all of the fair value of the assets acquired are concentrated in a single identifiable asset, then the transaction is accounted for as an asset acquisition rather than a business combination. In an asset acquisition, assets acquired are recorded at cost, goodwill is not recognized, and acquired in-process research and development with no alternative future use is charged to expense.
Intangible Assets	Intangible Assets Intangible assets acquired in a business combination are recorded at fair value, while intangible assets acquired in connection with an asset acquisition are recorded at cost. Payments to acquire intangible assets in an asset acquisition may include up-front payments and contingent consideration. With regard to contingent consideration in an asset acquisition, the Company recognizes regulatory milestones upon achievement, royalties in the period in which the underlying sales occur, and sales-based milestones when the milestone is deemed probable by the Company of being achieved. If contingent consideration is recognized subsequent to the acquisition date in an asset acquisition, the amount of such consideration is recorded as an addition to the cost basis of the intangible asset with a cumulative catch-up adjustment for amortization expense as if the additional amount of consideration had been accrued from the outset of the acquisition. Indefinite-lived intangible assets are subject to impairment testing until completion or abandonment of the associated research and development efforts. Definite-lived intangible assets are amortized to Cost of goods sold over the estimated useful lives of the assets based on the pattern in which the economic benefits of the intangible assets are consumed; if that pattern cannot be reliably determined, a straight-line basis is used. Intangible assets are reviewed for recoverability whenever events or changes in circumstances indicate that the carrying amount of the asset may not be recoverable. If an indicator of impairment exists, the Company compares the projected undiscounted cash flows to be generated by the asset to the intangible asset's carrying amount. If the projected undiscounted cash flows of the intangible asset are less than the carrying amount, an impairment loss is recognized within operating expenses and the intangible asset is written down to its fair value in the period in which the impairment occurs.
Product Revenue	Product Revenue Revenue from product sales is recognized at a point in time when the Company's customer is deemed to have obtained control of the product, which generally occurs upon receipt or acceptance by its customer. The amount of revenue the Company recognizes from product sales may vary due to rebates, chargebacks, and discounts provided under governmental and other programs, distribution-related fees, and other sales-related deductions. In order to determine the transaction price, the Company estimates, utilizing the expected value method, the amount of variable consideration to which the Company will be entitled. This estimate is based upon contracts with customers, healthcare providers, payors, and government agencies, statutorily-defined discounts applicable to government-funded programs, historical experience, estimated payor mix, and other relevant factors. The Company reviews its estimates of rebates, chargebacks, and other applicable provisions each period and records any necessary adjustments in the current period's net product sales. • Rebates: The Company's rebates include amounts paid to managed care organizations, group purchasing organizations, state Medicaid programs, and other rebate programs. The Company estimates reductions to product sales for each type of rebate and records an allowance for rebates in the same period in which the related product sales are recognized. The Company's liability for rebates consists of estimates for claims related to the current and prior periods that have not been paid and estimates for claims that will be made related to product that exists in the distribution channel at the end of the period. • Chargebacks and Discounts: The Company's reserves related to discounted pricing to eligible physicians, Veterans' Administration ("VA"), Public Health Services, and others (collectively, "qualified healthcare providers") represent the Company's estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices the Company charges to its customers (i.e., distributors and specialty pharmacies). The Company's customers charge the Company for the difference between what they pay for the products and the discounted selling price to the qualified healthcare providers. The Company estimates reductions to product sales for each type of chargeback and records an allowance for chargebacks in the same period that the related product sales are recognized. The Company's reserve for chargebacks consists of amounts for which it expects to issue credit based on expected sales by its customers to qualified healthcare providers and chargebacks that customers have claimed but for which the Company has not yet issued credit. • Distribution-Related Fees: The Company has written contracts with its customers that include terms for distribution-related fees. The Company estimates and records distribution and related fees due to its customers generally based on gross sales. • Other Sales-Related Deductions : The Company's other sales-related deductions include co-pay assistance programs and product returns. The Company estimates and records other sales-related deductions generally based on gross sales, written contracts, and other relevant factors. Consistent with industry practice, the Company generally offers its customers a limited right to return product purchased directly from the Company, which is principally based upon the product's expiration date. Product returned is generally not resalable given the nature of the Company's products and method of administration. The Company develops estimates for product returns based upon historical experience, shelf life of the product, and other relevant factors. The Company monitors product supply levels in the distribution channel, as well as sales by its customers, using product-specific data provided by its customers. If necessary, the Company's estimates of product returns may be adjusted in the future based on actual returns experience, known or expected changes in the marketplace, or other factors. Collaborative Arrangements The Company has entered into various collaborative arrangements to research, develop, manufacture, and commercialize products and/or product candidates. Although each of these arrangements is unique in nature, such arrangements involve a joint operating activity where both parties are active participants in the activities of the collaboration and exposed to significant risks and rewards dependent on the commercial success of the activities. In arrangements where the Company does not deem its collaborator to be its customer, payments to and from its collaborator are presented in the Company's statement of operations based on the nature of our business operations, the nature of the arrangement, including the contractual terms, and the nature of the payments. In general, the presentation of such amounts is summarized below. Nature/Type of Payment Statement of Operations Presentation Regeneron's share of profits or losses in connection with commercialization of products Collaboration revenue Reimbursement for manufacturing of commercial supplies Collaboration revenue Royalties and/or sales-based milestones earned Collaboration revenue Reimbursement of Regeneron's research and development expenses Reduction to Research and development expense Regeneron's obligation for its share of collaborator's research and development expenses Research and development expense Up-front, opt-in, and development milestone payments; and premiums paid on equity securities Acquired in-process research and development expense Reimbursement of Regeneron's commercialization-related expenses Reduction to Selling, general, and administrative expense Regeneron's obligation for its share of collaborator's commercialization-related expenses Selling, general, and administrative expense Regeneron's obligation to pay collaborator for its share of gross profits when Regeneron is deemed to be the principal Cost of goods sold Up-front and development milestones earned (when there is a combined unit of account which includes a license and providing research and development services) Other operating income In agreements involving multiple goods or services promised to be transferred to the Company's collaborator, the Company assesses, at the inception of the contract, whether each promise represents a separate obligation (i.e., is "distinct"), or whether such promises should be combined as a single unit of account. When the Company has a combined unit of account which includes a license and providing research and development services to its collaborator, recognition of up-front payments and development milestones earned from its collaborator is deferred (as a liability) and recognized over the development period (i.e., over time) typically using an input method on the basis of the Company's research and development costs incurred relative to the total expected cost which determines the extent of the Company's progress toward completion. The Company reviews its estimates each period and makes revisions to such estimates as necessary. When the Company is entitled to reimbursement of all or a portion of the expenses (e.g., research and development expenses) that it incurs under a collaboration, it records those reimbursable amounts in the period in which such costs are incurred. When the Company enters into an arrangement with another party to fund its research and development costs, the Company considers whether the costs that it may be obligated to repay represent a liability within the scope of Accounting Standards Codification ("ASC") 730-20, Research and Development . If the Company concludes that such funding does not represent a substantive and genuine transfer of risk, a liability is recorded. If the Company's collaborator performs research and development work or commercialization-related activities and the parties share the related costs, the Company also recognizes, as expense (e.g., research and development expense or selling, general, and administrative expense, as applicable) in the period when its collaborator incurs such expenses, the portion of the collaborator's expenses that the Company is obligated to reimburse. The Company's collaborators provide the Company with estimated expenses for the most recent fiscal quarter. The estimates are revised, if necessary, in subsequent periods if actual expenses differ from those estimates. Under certain of the Company's collaboration agreements, product sales and cost of sales may be recorded by the Company's collaborators as they are deemed to be the principal in the transaction. In arrangements where the Company: • supplies commercial product to its collaborator, the Company may be reimbursed for its manufacturing costs as commercial product is shipped to the collaborator (however, recognition of such cost reimbursements may be deferred until the product is sold by the Company's collaborator to third-party customers); • shares in any profits or losses arising from the commercialization of such products, the Company records its share of the variable consideration, representing net product sales less cost of goods sold and shared commercialization and other expenses, in the period in which such underlying sales occur and costs are incurred by the collaborator; • receives royalties and/or sales-based milestone payments from its collaborator, the Company recognizes such amounts in the period earned.
Research and Development Expenses	Research and Development Expenses Research and development expenses include costs attributable to the conduct of research and development programs, including the cost of salaries, payroll taxes, employee benefits, materials, supplies, depreciation on and maintenance of research equipment, costs related to research collaboration and licensing agreements, clinical trial expenses, the cost of services provided by outside contractors, including services related to the Company's clinical trials, the cost of manufacturing drug for use in research and development, amounts that the Company is obligated to reimburse to collaborators for research and development expenses that they incur, and the allocable portions of facility costs. Costs associated with research and development are expensed.
Stock-based Compensation	Stock-based Compensation The Company recognizes stock-based compensation expense for equity grants under the Company's long-term incentive plans (including stock options, restricted stock awards, and restricted stock units (both time-based and performance-based)) to employees and non-employee members of the Company's board of directors (as applicable) based on the grant-date fair value of those awards. The grant-date fair value of an award is generally recognized as compensation expense over the award's requisite service period. Stock-based compensation expense also includes an estimate, which is made at the time of grant, of the number of awards that are expected to be forfeited. The forfeiture rate estimate is calculated by considering both historical forfeiture experience and an estimate of expected future forfeitures for currently outstanding unvested awards. This estimate is reviewed at least annually and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The Company uses the Black-Scholes model to compute the estimated fair value of stock option awards. Additionally, the Company uses a Monte Carlo simulation to compute the estimated fair value of performance-based restricted stock units that are subject to vesting based on the Company’s attainment of pre-established criteria that include a market condition. For performance-based restricted stock units that contain a performance condition, the Company recognizes stock-based compensation expense if and when the Company determines that it is probable the performance condition will be achieved (based on the number of shares expected to be vested and issued). The Company reassesses the probability of achievement at each reporting period and adjusts compensation cost, as necessary. If there are any changes in the Company's probability assessment, the Company recognizes a cumulative catch-up adjustment in the period of the change in estimate, with the remaining unrecognized expense recognized prospectively over the remaining requisite service period. If the Company subsequently determines that the performance criteria are not met or are not expected to be met, any amounts previously recognized as compensation expense are reversed in the period when such determination is made.
Income Taxes	Income Taxes The provision for income taxes includes U.S. federal, state, local, and foreign taxes. Income taxes are accounted for under the liability method. Deferred tax assets and liabilities are recognized for the expected future tax consequences of events that have been included in the financial statements or tax returns, including deferred tax assets and liabilities for expected amounts of global intangible low-taxed income ("GILTI") inclusions. Deferred tax assets and liabilities are determined as the difference between the tax basis of assets and liabilities and their respective financial reporting amounts ("temporary differences") at enacted tax rates in effect for the years in which the differences are expected to reverse. A valuation allowance is established for deferred tax assets for which it is more likely than not that some portion or all of the deferred tax assets will not be realized. The Company recognizes the financial statement effects of a tax position when management's assessment is that there is more than a 50% probability that the position will be sustained upon examination by a taxing authority based upon its technical merits. Uncertain tax positions are recorded based upon certain recognition and measurement criteria. The Company re-evaluates uncertain tax positions and considers various factors, including, but not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, information obtained during in-process audit activities, and changes in facts or circumstances related to a tax position. The Company adjusts the amount of the liability to reflect any subsequent changes in the relevant facts and circumstances surrounding the uncertain tax positions. The Company recognizes interest and penalties related to income tax matters in income tax expense.
Per Share Data	Per Share Data Basic net income per share is computed by dividing net income by the weighted average number of shares of Common Stock and Class A Stock outstanding. Net income per share is presented on a combined basis, inclusive of Common Stock and Class A Stock outstanding, as each class of stock has equivalent economic rights. Basic net income per share excludes restricted stock until vested. Diluted net income per share includes the potential dilutive effect of common stock equivalents as if such securities were converted or exercised during the period, when the effect is dilutive. Common stock equivalents include outstanding stock options and unvested restricted stock under the Company's long-term incentive plans, which are included under the treasury stock method when dilutive.
Recently Issued Accounting Standards	Recently Issued Accounting Standards Standard/Description Effective Date Impact of Adoption on the Company's Financial Statements ASU 2023-09: In December 2023, the FASB issued amended guidance related to improvements to income tax disclosures . The amendments require annually (i) enhanced disclosures in connection with an entity's effective tax rate reconciliation and (ii) income taxes paid disaggregated by jurisdiction. January 1, 2025 No significant impact expected ASU 2024-03: In November 2024, the FASB issued new guidance which requires disclosure of disaggregated income statement expense information about specific categories (including purchases of inventory, employee compensation, depreciation, and intangible asset amortization) in the notes to financial statements. January 1, 2027 for annual reporting periods and January 1, 2028 for interim reporting periods Currently evaluating impact
Legal Matters	Costs associated with the Company's involvement in legal proceedings are expensed as incurred

Business Overview and Summary_3

Business Overview and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2024
Accounting Policies [Abstract]
Schedule of significant segment expenses	In addition to the significant expense categories included within consolidated net income presented on the Company's Consolidated Statements of Operations, see below for disaggregated amounts that comprise research and development expenses: Year Ended December 31, (In millions) 2024 2023 2022 Direct research and development expenses (a) $ 1,588.8 $ 1,295.6 $ 1,042.9 Indirect research and development expenses: Payroll and benefits 1,681.7 1,537.0 1,195.5 Lab supplies and other research and development costs 241.5 210.6 181.0 Occupancy and other operating costs 614.9 518.2 508.5 Total indirect research and development expenses 2,538.1 2,265.8 1,885.0 Clinical manufacturing costs 1,195.9 1,053.9 938.3 Reimbursement of research and development expenses by collaborators (190.8) (176.3) (273.7) Total research and development expenses $ 5,132.0 $ 4,439.0 $ 3,592.5 (a) Direct research and development expenses are comprised primarily of costs paid to third parties for clinical and product development activities, and the portion of research and development expenses incurred by our collaborators that we are obligated to reimburse.
Schedule of estimated useful lives of property, plant, and equipment	The estimated useful lives of property, plant, and equipment are as follows: Building and improvements 10–50 years Laboratory and other equipment 3–10 years Furniture and fixtures 5 years Property, plant, and equipment, net consists of the following: As of December 31, (In millions) 2024 2023 Building and improvements $ 2,573.2 $ 2,423.1 Leasehold improvements 154.5 133.9 Laboratory equipment 1,494.5 1,384.5 Computer equipment and software 450.8 389.7 Furniture, office equipment, and other 203.8 165.9 Land 288.2 283.1 Construction in progress 1,721.6 1,345.0 6,886.6 6,125.2 Accumulated depreciation and amortization (2,286.9) (1,978.8) $ 4,599.7 $ 4,146.4
Summary of presentation in statement of operations of payments to and from collaborators	In arrangements where the Company does not deem its collaborator to be its customer, payments to and from its collaborator are presented in the Company's statement of operations based on the nature of our business operations, the nature of the arrangement, including the contractual terms, and the nature of the payments. In general, the presentation of such amounts is summarized below. Nature/Type of Payment Statement of Operations Presentation Regeneron's share of profits or losses in connection with commercialization of products Collaboration revenue Reimbursement for manufacturing of commercial supplies Collaboration revenue Royalties and/or sales-based milestones earned Collaboration revenue Reimbursement of Regeneron's research and development expenses Reduction to Research and development expense Regeneron's obligation for its share of collaborator's research and development expenses Research and development expense Up-front, opt-in, and development milestone payments; and premiums paid on equity securities Acquired in-process research and development expense Reimbursement of Regeneron's commercialization-related expenses Reduction to Selling, general, and administrative expense Regeneron's obligation for its share of collaborator's commercialization-related expenses Selling, general, and administrative expense Regeneron's obligation to pay collaborator for its share of gross profits when Regeneron is deemed to be the principal Cost of goods sold Up-front and development milestones earned (when there is a combined unit of account which includes a license and providing research and development services) Other operating income
Summary of Recently Issued Accounting Standards	Standard/Description Effective Date Impact of Adoption on the Company's Financial Statements ASU 2023-09: In December 2023, the FASB issued amended guidance related to improvements to income tax disclosures . The amendments require annually (i) enhanced disclosures in connection with an entity's effective tax rate reconciliation and (ii) income taxes paid disaggregated by jurisdiction. January 1, 2025 No significant impact expected ASU 2024-03: In November 2024, the FASB issued new guidance which requires disclosure of disaggregated income statement expense information about specific categories (including purchases of inventory, employee compensation, depreciation, and intangible asset amortization) in the notes to financial statements. January 1, 2027 for annual reporting periods and January 1, 2028 for interim reporting periods Currently evaluating impact

Product Sales (Tables)

Product Sales (Tables)	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Schedule of product sales	Net product sales consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 EYLEA HD ® U.S. $ 1,201.1 $ 165.8 $ — EYLEA ® U.S. 4,767.1 5,719.6 6,264.6 Total EYLEA HD and EYLEA U.S. 5,968.2 5,885.4 6,264.6 Libtayo ® U.S. 787.3 538.8 374.5 Libtayo (a) Rest of world 429.5 324.3 73.0 Total Libtayo Global 1,216.8 863.1 447.5 Praluent ® U.S. 241.7 182.4 130.0 Evkeeza ® U.S. 125.7 77.3 48.6 Inmazeb ® U.S. 76.8 69.8 3.0 $ 7,629.2 $ 7,078.0 $ 6,893.7 (a) Effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide and, as a result, began recording net product sales of Libtayo outside the United States. See Note 3 for further details. Amounts recognized in the Company's Statements of Operations in connection with its collaborations with Sanofi are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Antibody: Regeneron's share of profits Collaboration revenue $ 3,923.5 $ 3,136.5 $ 2,082.0 * Sales-based milestones earned Collaboration revenue $ — $ 50.0 $ 100.0 Reimbursement for manufacturing of commercial supplies Collaboration revenue $ 607.9 $ 613.0 $ 633.7 Other Collaboration revenue $ — $ — $ 28.7 Regeneron's obligation for its share of Sanofi R&D expenses, net of reimbursement of R&D expenses (R&D expense)/Reduction of R&D expense $ (46.8) $ (83.7) $ 43.0 Reimbursement of commercialization-related expenses Reduction of SG&A expense $ 655.4 $ 534.4 $ 437.4 Immuno-oncology (a) : Regeneron's share of profits in connection with commercialization of Libtayo outside the United States Collaboration revenue $ — $ — $ 6.7 Reimbursement for manufacturing of ex-U.S. commercial supplies Collaboration revenue $ — $ — $ 4.6 Reimbursement of R&D expenses Reduction of R&D expense $ — $ — $ 42.7 Reimbursement of commercialization-related expenses, net of Regeneron's obligation for its share of Sanofi commercialization-related expenses Reduction of SG&A expense $ — $ — $ 21.5 Regeneron's obligation for Sanofi's share of Libtayo U.S. gross profits Cost of goods sold $ — $ — $ (70.1) Amounts recognized in connection with up-front payments received Other operating income $ — $ — $ 35.1 * Net of one-time payment of $56.9 million to Sanofi in connection with the amendment to the Antibody License and Collaboration Agreement (a) As described within the " Immuno-Oncology " section below, effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide. Amounts recognized in the Company's Statements of Operations in connection with its Bayer collaboration are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Regeneron's share of profits Collaboration revenue $ 1,403.3 $ 1,376.4 $ 1,317.4 Reimbursement for manufacturing of ex-U.S. commercial supplies Collaboration revenue $ 95.7 $ 111.1 $ 91.4 One-time payment in connection with change in Japan arrangement Collaboration revenue $ — $ — $ 21.9 Regeneron's obligation for its share of Bayer R&D expenses, net of reimbursement of R&D expenses (R&D expense)/Reduction of R&D expense $ (48.5) $ (44.0) $ 16.7 Amounts recognized in the Company's Statements of Operations in connection with its Roche collaboration are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Regeneron's share of profits Collaboration revenue $ 1.4 $ 224.3 $ 627.3 Other Collaboration revenue $ — $ (13.3) $ —
Schedules of concentration of risk, by risk factor	Sales to each of these customers as a percentage of the Company's total gross product revenue are as follows: Year Ended December 31, 2024 2023 2022 Besse Medical, a subsidiary of Cencora, Inc. 50 % 51 % 55 % McKesson Corporation 24 % 25 % 28 %
Sales related deductions activity	The following table summarizes the provisions, and credits/payments, for sales-related deductions: (In millions) Rebates, Chargebacks, Distribution- Other Sales- Total Balance as of December 31, 2021 $ 214.6 $ 80.0 $ 67.6 $ 362.2 Provisions 1,537.3 431.1 141.1 2,109.5 Credits/payments (1,398.0) (399.7) (127.2) (1,924.9) Balance as of December 31, 2022 353.9 111.4 81.5 546.8 Provisions 2,074.5 439.2 155.3 2,669.0 Credits/payments (1,972.7) (388.3) (157.5) (2,518.5) Balance as of December 31, 2023 455.7 162.3 79.3 697.3 Provisions 2,447.3 462.7 143.0 3,053.0 Credits/payments (2,363.9) (497.2) (128.8) (2,989.9) Balance as of December 31, 2024 $ 539.1 $ 127.8 $ 93.5 $ 760.4

Collaboration, License, and O_2

Collaboration, License, and Other Agreements (Tables)	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Schedule of collaboration revenue	Net product sales consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 EYLEA HD ® U.S. $ 1,201.1 $ 165.8 $ — EYLEA ® U.S. 4,767.1 5,719.6 6,264.6 Total EYLEA HD and EYLEA U.S. 5,968.2 5,885.4 6,264.6 Libtayo ® U.S. 787.3 538.8 374.5 Libtayo (a) Rest of world 429.5 324.3 73.0 Total Libtayo Global 1,216.8 863.1 447.5 Praluent ® U.S. 241.7 182.4 130.0 Evkeeza ® U.S. 125.7 77.3 48.6 Inmazeb ® U.S. 76.8 69.8 3.0 $ 7,629.2 $ 7,078.0 $ 6,893.7 (a) Effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide and, as a result, began recording net product sales of Libtayo outside the United States. See Note 3 for further details. Amounts recognized in the Company's Statements of Operations in connection with its collaborations with Sanofi are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Antibody: Regeneron's share of profits Collaboration revenue $ 3,923.5 $ 3,136.5 $ 2,082.0 * Sales-based milestones earned Collaboration revenue $ — $ 50.0 $ 100.0 Reimbursement for manufacturing of commercial supplies Collaboration revenue $ 607.9 $ 613.0 $ 633.7 Other Collaboration revenue $ — $ — $ 28.7 Regeneron's obligation for its share of Sanofi R&D expenses, net of reimbursement of R&D expenses (R&D expense)/Reduction of R&D expense $ (46.8) $ (83.7) $ 43.0 Reimbursement of commercialization-related expenses Reduction of SG&A expense $ 655.4 $ 534.4 $ 437.4 Immuno-oncology (a) : Regeneron's share of profits in connection with commercialization of Libtayo outside the United States Collaboration revenue $ — $ — $ 6.7 Reimbursement for manufacturing of ex-U.S. commercial supplies Collaboration revenue $ — $ — $ 4.6 Reimbursement of R&D expenses Reduction of R&D expense $ — $ — $ 42.7 Reimbursement of commercialization-related expenses, net of Regeneron's obligation for its share of Sanofi commercialization-related expenses Reduction of SG&A expense $ — $ — $ 21.5 Regeneron's obligation for Sanofi's share of Libtayo U.S. gross profits Cost of goods sold $ — $ — $ (70.1) Amounts recognized in connection with up-front payments received Other operating income $ — $ — $ 35.1 * Net of one-time payment of $56.9 million to Sanofi in connection with the amendment to the Antibody License and Collaboration Agreement (a) As described within the " Immuno-Oncology " section below, effective July 1, 2022, the Company obtained the exclusive right to develop, commercialize, and manufacture Libtayo worldwide. Amounts recognized in the Company's Statements of Operations in connection with its Bayer collaboration are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Regeneron's share of profits Collaboration revenue $ 1,403.3 $ 1,376.4 $ 1,317.4 Reimbursement for manufacturing of ex-U.S. commercial supplies Collaboration revenue $ 95.7 $ 111.1 $ 91.4 One-time payment in connection with change in Japan arrangement Collaboration revenue $ — $ — $ 21.9 Regeneron's obligation for its share of Bayer R&D expenses, net of reimbursement of R&D expenses (R&D expense)/Reduction of R&D expense $ (48.5) $ (44.0) $ 16.7 Amounts recognized in the Company's Statements of Operations in connection with its Roche collaboration are as follows: Statement of Operations Classification Year Ended December 31, (In millions) 2024 2023 2022 Regeneron's share of profits Collaboration revenue $ 1.4 $ 224.3 $ 627.3 Other Collaboration revenue $ — $ (13.3) $ —
Schedule of accounts receivable and deferred revenue information	The following table summarizes contract balances in connection with the Company's Antibody Collaboration with Sanofi: As of December 31, (In millions) 2024 2023 Accounts receivable, net $ 1,216.2 $ 1,029.1 Deferred revenue $ 571.7 $ 427.7 The following table summarizes contract balances in connection with the Company's Bayer collaboration: As of December 31, (In millions) 2024 2023 Accounts receivable, net $ 349.9 $ 381.7 Deferred revenue $ 216.3 $ 138.2

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2024
Investments, Debt and Equity Securities [Abstract]
Available-for-sale debt securities	The following tables summarize the Company's investments in available-for-sale debt securities: (In millions) Amortized Unrealized Fair As of December 31, 2024 Cost Basis Gains Losses Value Corporate bonds $ 8,226.9 $ 25.1 $ (31.4) $ 8,220.6 U.S. government and government agency obligations 4,820.5 3.4 (6.9) 4,817.0 Commercial paper 548.3 0.4 — 548.7 Certificates of deposit 380.6 0.5 — 381.1 Asset-backed securities 279.0 0.6 (0.3) 279.3 Sovereign bonds 82.7 0.1 (0.4) 82.4 $ 14,338.0 $ 30.1 $ (39.0) $ 14,329.1 As of December 31, 2023 Corporate bonds $ 6,492.5 $ 10.4 $ (104.9) $ 6,398.0 U.S. government and government agency obligations 4,839.6 2.4 (8.6) 4,833.4 Commercial paper 636.8 0.2 (0.2) 636.8 Certificates of deposit 520.8 0.6 — 521.4 Asset-backed securities 88.2 0.1 (1.2) 87.1 Sovereign bonds 58.1 — (0.9) 57.2 $ 12,636.0 $ 13.7 $ (115.8) $ 12,533.9
Marketable securities, based on contractual maturity dates	The fair values of available-for-sale debt securities by contractual maturity consist of the following: As of December 31, (In millions) 2024 2023 Maturities within one year $ 6,524.3 $ 8,114.8 Maturities after one year through five years 7,804.8 4,414.5 Maturities after five years — 4.6 $ 14,329.1 $ 12,533.9
Fair value and unrealized losses of marketable securities	The following table shows the fair value and gross unrealized losses by category and disaggregated by the length of time that the Company's available-for-sale debt securities have been in a continuous unrealized loss position. Less than 12 Months 12 Months or Greater Total (In millions) As of December 31, 2024 Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Corporate bonds $ 7,175.8 $ (14.2) $ 1,044.8 $ (17.2) $ 8,220.6 $ (31.4) U.S. government and government agency obligations 4,675.3 (6.2) 141.7 (0.7) 4,817.0 (6.9) Sovereign bonds 63.3 (0.3) 19.1 (0.1) 82.4 (0.4) Asset-backed securities 265.4 (0.3) 13.9 — 279.3 (0.3) $ 12,179.8 $ (21.0) $ 1,219.5 $ (18.0) $ 13,399.3 $ (39.0) As of December 31, 2023 Corporate bonds $ 2,363.3 $ (2.4) $ 4,034.7 $ (102.5) $ 6,398.0 $ (104.9) U.S. government and government agency obligations 4,780.6 (6.0) 52.7 (2.6) 4,833.3 (8.6) Sovereign bonds 12.4 (0.1) 44.8 (0.8) 57.2 (0.9) Commercial paper 636.8 (0.2) — — 636.8 (0.2) Asset-backed securities 61.8 (0.3) 25.3 (0.9) 87.1 (1.2) $ 7,854.9 $ (9.0) $ 4,157.5 $ (106.8) $ 12,012.4 $ (115.8)

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Schedule of assets measured at fair value on a recurring basis	The table below summarizes the Company's assets and liabilities which are measured at fair value on a recurring basis. The following fair value hierarchy is used to classify assets and liabilities, based on inputs to valuation techniques utilized to measure fair value: • Level 1 - Quoted prices in active markets for identical assets or liabilities • Level 2 - Significant other observable inputs, such as quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, or model-based valuations in which significant inputs used are observable • Level 3 - Significant other unobservable inputs (In millions) Fair Value Measurements at Reporting Date As of December 31, 2024 Fair Value Level 1 Level 2 Level 3 Assets: Cash equivalents $ 1,452.2 $ 1,264.2 $ 188.0 $ — Available-for-sale debt securities: Corporate bonds 8,220.6 — 8,220.6 — U.S. government and government agency obligations 4,817.0 — 4,817.0 — Commercial paper 548.7 — 548.7 — Certificates of deposit 381.1 — 381.1 — Asset-backed securities 279.3 — 279.3 — Sovereign bonds 82.4 — 82.4 — Equity securities (unrestricted) 1,052.1 1,052.1 — — Equity securities (restricted) (a) 43.2 43.2 — — Total assets $ 16,876.6 $ 2,359.5 $ 14,517.1 $ — Liabilities: Contingent consideration $ 52.3 $ — $ — $ 52.3 As of December 31, 2023 Assets: Cash equivalents $ 928.1 $ 6.4 $ 921.7 $ — Available-for-sale debt securities: Corporate bonds 6,398.0 — 6,398.0 — U.S. government and government agency obligations 4,833.4 — 4,833.4 — Commercial paper 636.8 — 636.8 — Certificates of deposit 521.4 — 521.4 — Asset-backed securities 87.1 — 87.1 — Sovereign bonds 57.2 — 57.2 — Equity securities (unrestricted) 864.5 864.5 — — Equity securities (restricted) 112.9 112.9 — — Total assets $ 14,439.4 $ 983.8 $ 13,455.6 $ — Liabilities: Contingent consideration $ 43.7 $ — $ — $ 43.7 (a) Includes equity securities which are subject to transfer restrictions that expire in April 2026

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2024
Inventory Disclosure [Abstract]
Schedule of inventory	Inventories consist of the following: As of December 31, (In millions) 2024 2023 Raw materials $ 879.5 $ 789.3 Work-in-process 1,342.3 1,121.8 Finished goods 139.8 147.3 Deferred costs 725.7 522.1 $ 3,087.3 $ 2,580.5

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of property, plant and equipment	The estimated useful lives of property, plant, and equipment are as follows: Building and improvements 10–50 years Laboratory and other equipment 3–10 years Furniture and fixtures 5 years Property, plant, and equipment, net consists of the following: As of December 31, (In millions) 2024 2023 Building and improvements $ 2,573.2 $ 2,423.1 Leasehold improvements 154.5 133.9 Laboratory equipment 1,494.5 1,384.5 Computer equipment and software 450.8 389.7 Furniture, office equipment, and other 203.8 165.9 Land 288.2 283.1 Construction in progress 1,721.6 1,345.0 6,886.6 6,125.2 Accumulated depreciation and amortization (2,286.9) (1,978.8) $ 4,599.7 $ 4,146.4

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of intangible assets	Intangible assets, net consist of the following: As of December 31, 2024 2023 (In millions) Estimated Useful Life Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross carrying Amount Accumulated Amortization Net Carrying Amount Acquired product rights - Libtayo 13 years $ 1,347.7 $ (254.3) $ 1,093.4 $ 1,119.1 $ (126.7) $ 992.4 Other intangibles 8 years 10.0 (7.6) 2.4 10.0 (6.3) 3.7 Acquired in-process research and development Indefinite 52.8 — 52.8 42.5 — 42.5 $ 1,410.5 $ (261.9) $ 1,148.6 $ 1,171.6 $ (133.0) $ 1,038.6

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consist of the following: As of December 31, (In millions) 2024 2023 Accrued payroll and related costs $ 640.9 $ 618.2 Accrued clinical expenses 315.7 292.2 Accrued sales-related costs 786.2 780.8 Income tax-related costs 213.2 11.7 Other accrued expenses and liabilities 571.1 655.0 $ 2,527.1 $ 2,357.9

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Summary of issued senior unsecured notes	Long-term debt, net of underwriting discounts and offering expenses (which are being amortized as additional interest expense over the period of issuance through maturity), consists of the following: As of December 31, (In millions) 2024 2023 1.750% Senior Notes due September 2030 $ 1,243.3 $ 1,242.2 2.800% Senior Notes due September 2050 741.1 740.7 $ 1,984.4 $ 1,982.9

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Schedule of amounts recognized in the condensed consolidated balance sheet	Amounts recognized in the Consolidated Balance Sheet related to the Company's leases are included in the table below. As of December 31, (In millions) Classification 2024 2023 Assets: Finance lease right-of-use assets Property, plant, and equipment, net (a) $ 591.2 $ 605.7 Operating lease right-of-use assets Other noncurrent assets (b) 217.4 78.0 $ 808.6 $ 683.7 Liabilities: Finance lease liabilities - noncurrent Finance lease liabilities $ 720.0 $ 720.0 Operating lease liabilities - current Accrued expenses and other current liabilities 30.3 19.0 Operating lease liabilities - noncurrent Other noncurrent liabilities 204.1 68.7 $ 954.4 $ 807.7 (a) Finance lease right-of-use assets were recorded net of accumulated amortization of $148.4 million and $133.9 million as of December 31, 2024 and 2023, respectively. (b) Operating lease right-of-use assets were recorded net of accumulated amortization of $78.4 million and $44.6 million as of December 31, 2024 and 2023, respectively.
Schedule of lease cost and other information	Lease costs consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Operating lease costs $ 36.5 $ 19.2 $ 12.4 Finance lease costs: Amortization of finance lease right-of-use assets 14.5 14.5 14.5 Interest on finance lease liabilities 46.1 45.0 21.6 Total finance lease costs 60.6 59.5 36.1 Total lease costs $ 97.1 $ 78.7 $ 48.5 Other information related to the Company's leases includes the following: As of December 31, 2024 2023 Weighted-average remaining lease term (in years): Finance leases 2.2 3.2 Operating leases 7.2 7.4 Weighted-average discount rate: Finance leases 5.03% 5.08% Operating leases 5.52% 5.38% Supplemental cash flow information related to the Company's leases includes the following: Year Ended December 31, (In millions) 2024 2023 2022 Cash paid for amounts included in the measurement of operating lease liabilities (included within cash flows from operating activities) $ 41.4 $ 22.5 $ 7.7 Right-of-use assets obtained in exchange for operating lease liabilities $ 188.1 $ 31.9 $ 35.1
Schedule of maturities of operating lease liabilities	The following is a maturity analysis of the Company's lease liabilities as of December 31, 2024: (In millions) Finance Leases Operating Leases Total 2025 $ 38.6 $ 43.1 $ 81.7 2026 36.8 44.8 81.6 2027 729.1 42.6 771.7 2028 — 33.2 33.2 2029 — 30.3 30.3 Thereafter — 96.9 96.9 Total undiscounted lease payments 804.5 290.9 1,095.4 Imputed interest (84.5) (56.5) (141.0) Total lease liabilities $ 720.0 $ 234.4 $ 954.4
Schedule of maturities of finance lease liabilities	The following is a maturity analysis of the Company's lease liabilities as of December 31, 2024: (In millions) Finance Leases Operating Leases Total 2025 $ 38.6 $ 43.1 $ 81.7 2026 36.8 44.8 81.6 2027 729.1 42.6 771.7 2028 — 33.2 33.2 2029 — 30.3 30.3 Thereafter — 96.9 96.9 Total undiscounted lease payments 804.5 290.9 1,095.4 Imputed interest (84.5) (56.5) (141.0) Total lease liabilities $ 720.0 $ 234.4 $ 954.4

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2024
Equity [Abstract]
Class of treasury stock	The table below summarizes the shares of the Company's Common Stock that the Company repurchased and the cost of such shares, which were recorded as Treasury Stock. Year Ended December 31, (In millions) 2024 2023 2022 Number of shares 2.8 2.9 3.3 Total cost of shares $ 2,613.9 $ 2,214.6 $ 2,099.8

Long-Term Incentive Plans (Tabl

Long-Term Incentive Plans (Tables)	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of transactions involving stock option awards	The table below summarizes the activity related to stock option awards under the Company's Incentive Plans during 2024. Number of Shares (In millions) Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term Intrinsic Value (In millions) Outstanding as of December 31, 2023 14.2 $ 534.13 2024: Granted 1.9 $ 786.79 Forfeited (0.2) $ 698.92 Exercised (3.2) $ 454.70 Outstanding as of December 31, 2024 12.7 $ 588.47 6.1 years $ 1,891.0 Vested and expected to vest as of December 31, 2024 12.3 $ 582.36 6.0 years $ 1,888.5 Exercisable as of December 31, 2024 8.3 $ 495.19 4.7 years $ 1,834.8
Schedule of weighted-average exercise prices and weighted-average grant-date fair values of options issued	The table below summarizes the weighted-average exercise prices and weighted-average grant-date fair values of options issued during the years ended December 31, 2024, 2023, and 2022. Number of Options Granted (In millions) Weighted-Average Exercise Price Weighted-Average Fair Value 2024: Exercise price equal to Market Price 1.9 $ 786.79 $ 235.32 2023: Exercise price equal to Market Price 1.6 $ 835.91 $ 264.37 2022: Exercise price equal to Market Price 2.0 $ 705.02 $ 220.88
Schedule of weighted-average values of assumptions used in computing fair value of option grants	The following table summarizes the weighted average values of the assumptions used in computing the fair value of option grants during 2024, 2023, and 2022. 2024 2023 2022 Expected volatility 25 % 26 % 28 % Expected lives from grant date 5.0 years 5.1 years 5.2 years Expected dividend yield 0 % 0 % 0 % Risk-free interest rate 4.11 % 4.29 % 3.50 % The following table summarizes the weighted average values of the assumptions used in computing the fair value of PSUs that were granted during 2022. The Company did not grant PSUs during 2024 and 2023. 2022 Expected volatility 32% Expected dividend yield 0% Risk-free interest rate 3.3%
Schedule of activity related to restricted stock awards	A summary of the Company's activity related to restricted stock awards and time-based restricted stock units (excluding performance-based restricted stock units, which are detailed further below) (collectively, "restricted stock") during 2024 is summarized below. Number of Shares/Units (In millions) Weighted-Average Grant Unvested as of December 31, 2023 2.3 $ 705.37 2024: Granted 1.0 $ 787.15 Vested (0.7) $ 617.50 Forfeited (0.1) $ 704.57 Unvested as of December 31, 2024 2.5 $ 760.35

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Schedule of income before income tax	Components of income before income taxes consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 United States $ (411.3) $ (362.3) $ 839.9 Foreign 5,191.2 4,561.6 4,018.9 $ 4,779.9 $ 4,199.3 $ 4,858.8
Schedule of components of income tax expense	Components of income tax expense consist of the following: Year Ended December 31, (In millions) 2024 2023 2022 Current: Federal $ 1,092.6 $ 667.9 $ 968.5 State (11.1) 7.7 7.4 Foreign 43.1 407.9 290.9 Total current tax expense 1,124.6 1,083.5 1,266.8 Deferred: Federal (935.5) (834.5) (797.7) State (4.9) (6.5) (2.7) Foreign 183.1 3.2 54.0 Total deferred tax benefit (757.3) (837.8) (746.4) $ 367.3 $ 245.7 $ 520.4
Schedule of effective income tax rate reconciliation	A reconciliation of the U.S. statutory income tax rate to the Company's effective income tax rate is as follows: Year Ended December 31, 2024 2023 2022 U.S. federal statutory tax rate 21.0 % 21.0 % 21.0 % Stock-based compensation (4.9) (4.6) (2.9) Taxation of non-U.S. operations (4.0) (6.6) (5.5) Income tax credits (3.5) (3.2) (2.0) Foreign-derived intangible income deduction (0.8) (0.3) (1.0) Other permanent differences (0.1) (0.4) 1.1 Effective income tax rate 7.7 % 5.9 % 10.7 %
Schedule of deferred tax assets and liabilities	Significant components of the Company's deferred tax assets and liabilities are as follows: As of December 31, (In millions) 2024 2023 Deferred tax assets: Capitalized research and development expenses $ 2,530.2 $ 1,728.2 Deferred compensation 419.7 413.6 Accrued expenses 185.0 214.1 Fixed assets and intangible assets 145.1 154.8 Tax attribute carryforwards 84.1 88.7 Other 43.0 26.4 Total deferred tax assets 3,407.1 2,625.8 Deferred tax liabilities: Unrealized gains on investments (93.0) (50.4) Net deferred tax assets $ 3,314.1 $ 2,575.4
Schedule of unrecognized tax benefits	The following table reconciles the beginning and ending amounts of unrecognized tax benefits: (In millions) 2024 2023 2022 Balance as of January 1 $ 696.4 $ 542.8 $ 410.9 Gross increases related to current year tax positions 353.5 153.4 136.9 Gross increases (decreases) related to prior year tax positions 264.8 3.2 (5.0) Gross decreases due to settlements and lapse of statutes of limitations (1.0) (3.0) — Balance as of December 31 $ 1,313.7 $ 696.4 $ 542.8

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Basic and diluted net income (loss) per share	The calculations of basic and diluted net income per share are as follows: Year Ended December 31, (In millions, except per share data) 2024 2023 2022 Net income - basic and diluted $ 4,412.6 $ 3,953.6 $ 4,338.4 Weighted average shares - basic 107.9 106.7 107.1 Effect of dilutive securities: Stock options 4.8 4.9 4.9 Restricted stock awards and restricted stock units 2.4 2.1 1.5 Weighted average shares - diluted 115.1 113.7 113.5 Net income per share - basic $ 40.90 $ 37.05 $ 40.51 Net income per share - diluted $ 38.34 $ 34.77 $ 38.22
Antidilutive securities	Shares which have been excluded from diluted per share amounts because their effect would have been antidilutive include the following: Year Ended December 31, (Shares in millions) 2024 2023 2022 Stock options 1.6 1.8 2.3

Statement of Cash Flows (Tables

Statement of Cash Flows (Tables)	12 Months Ended
	Dec. 31, 2024
Cash and Cash Equivalents [Abstract]
Schedule of cash and cash equivalents	The following provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets to the total of the same such amounts shown in the Consolidated Statements of Cash Flows: December 31, (In millions) 2024 2023 2022 Cash and cash equivalents $ 2,488.2 $ 2,730.0 $ 3,105.9 Restricted cash included in Other current assets 0.8 — — Restricted cash included in Other noncurrent assets — 7.8 13.5 Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 2,489.0 $ 2,737.8 $ 3,119.4
Schedule of restrictions on cash and cash equivalents	The following provides a reconciliation of cash, cash equivalents, and restricted cash reported within the Consolidated Balance Sheets to the total of the same such amounts shown in the Consolidated Statements of Cash Flows: December 31, (In millions) 2024 2023 2022 Cash and cash equivalents $ 2,488.2 $ 2,730.0 $ 3,105.9 Restricted cash included in Other current assets 0.8 — — Restricted cash included in Other noncurrent assets — 7.8 13.5 Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows $ 2,489.0 $ 2,737.8 $ 3,119.4
Summary of non-cash investing and financing activities	Supplemental disclosure of non-cash investing and financing activities As of December 31, (In millions) 2024 2023 2022 Accrued capital expenditures $ 151.6 $ 75.4 $ 70.8 Accrued contingent consideration in connection with acquisitions $ 62.7 $ 71.6 $ 135.5

Business Overview and Summary_4

Business Overview and Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of business segments | segment	1
Provision for doubtful accounts	$ 0	$ 0
Allowance for doubtful accounts receivable, current	$ 0	$ 0
Two Individual Customers | Customer concentration risk | Accounts receivable
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Concentration risk, percentage	79%	83%

Business Overview and Summary_5

Business Overview and Summary of Significant Accounting Policies - Schedule of Significant Segment Expenses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total research and development expenses	$ 5,132	$ 4,439	$ 3,592.5
Reportable Segment
Segment Reporting Information [Line Items]
Reimbursement of research and development expenses by collaborators	(190.8)	(176.3)	(273.7)
Total research and development expenses	5,132	4,439	3,592.5
Reportable Segment | Clinical manufacturing costs
Segment Reporting Information [Line Items]
Total research and development expenses	1,195.9	1,053.9	938.3
Reportable Segment | Direct research and development expenses(a)
Segment Reporting Information [Line Items]
Total research and development expenses	1,588.8	1,295.6	1,042.9
Reportable Segment | Indirect research and development expenses:
Segment Reporting Information [Line Items]
Total research and development expenses	2,538.1	2,265.8	1,885
Reportable Segment | Indirect research and development expenses: | Payroll and benefits
Segment Reporting Information [Line Items]
Total research and development expenses	1,681.7	1,537	1,195.5
Reportable Segment | Indirect research and development expenses: | Lab supplies and other research and development costs
Segment Reporting Information [Line Items]
Total research and development expenses	241.5	210.6	181
Reportable Segment | Indirect research and development expenses: | Occupancy and other operating costs
Segment Reporting Information [Line Items]
Total research and development expenses	$ 614.9	$ 518.2	$ 508.5

Business Overview and Summary_6

Business Overview and Summary of Significant Accounting Policies - Schedule of Estimated Useful Lives (Details)	Dec. 31, 2024
Building and improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	10 years
Building and improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	50 years
Laboratory equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	3 years
Laboratory equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	10 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Estimated useful life (in years)	5 years

Product Sales - Schedule of Net

Product Sales - Schedule of Net Product Sales (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 14,202	$ 13,117.2	$ 12,172.9
Net product sales
Disaggregation of Revenue [Line Items]
Revenues	7,629.2	7,078	6,893.7
Libtayo
Disaggregation of Revenue [Line Items]
Revenues	1,216.8	863.1	447.5
United States | ELYEA HD And EYLEA
Disaggregation of Revenue [Line Items]
Revenues	5,968.2	5,885.4	6,264.6
United States | ELYEA HD
Disaggregation of Revenue [Line Items]
Revenues	1,201.1	165.8	0
United States | EYLEA
Disaggregation of Revenue [Line Items]
Revenues	4,767.1	5,719.6	6,264.6
United States | Libtayo
Disaggregation of Revenue [Line Items]
Revenues	787.3	538.8	374.5
United States | Praluent
Disaggregation of Revenue [Line Items]
Revenues	241.7	182.4	130
United States | Evkeeza
Disaggregation of Revenue [Line Items]
Revenues	125.7	77.3	48.6
United States | Inmazeb
Disaggregation of Revenue [Line Items]
Revenues	76.8	69.8	3
Rest Of World | Libtayo
Disaggregation of Revenue [Line Items]
Revenues	$ 429.5	$ 324.3	$ 73

Product Sales - Narrative (Deta

Product Sales - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 6,211.9	$ 5,667.3
Trade Accounts Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, net	$ 4,278	$ 3,888

Product Sales - Schedule of Con

Product Sales - Schedule of Concentration of Risk, by Risk Factor (Details) - Gross Product Revenue - Customer concentration risk	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Besse Medical, a subsidiary of Cencora, Inc.
Concentration Risk [Line Items]
Concentration risk, percentage	50%	51%	55%
McKesson Corporation
Concentration Risk [Line Items]
Concentration risk, percentage	24%	25%	28%

Product Sales - Schedule of Sal

Product Sales - Schedule of Sales Related Deductions Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 697.3	$ 546.8	$ 362.2
Provisions	3,053	2,669	2,109.5
Credits/payments	(2,989.9)	(2,518.5)	(1,924.9)
Ending Balance	760.4	697.3	546.8
Rebates, Chargebacks, and Discounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	455.7	353.9	214.6
Provisions	2,447.3	2,074.5	1,537.3
Credits/payments	(2,363.9)	(1,972.7)	(1,398)
Ending Balance	539.1	455.7	353.9
Distribution- Related Fees
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	162.3	111.4	80
Provisions	462.7	439.2	431.1
Credits/payments	(497.2)	(388.3)	(399.7)
Ending Balance	127.8	162.3	111.4
Other Sales- Related Deductions
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	79.3	81.5	67.6
Provisions	143	155.3	141.1
Credits/payments	(128.8)	(157.5)	(127.2)
Ending Balance	$ 93.5	$ 79.3	$ 81.5

Collaboration, License, and O_3

Collaboration, License, and Other Agreements - Schedule of Collaboration Revenue Earned From Sanofi (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 14,202	$ 13,117.2	$ 12,172.9
One time payment			56.9
Sanofi Collaboration Agreement, Antibody | Collaboration revenue | Regeneron's share of profits
Disaggregation of Revenue [Line Items]
Revenues	3,923.5	3,136.5	2,082
Sanofi Collaboration Agreement, Antibody | Collaboration revenue | Sales-based milestones earned
Disaggregation of Revenue [Line Items]
Revenues	0	50	100
Sanofi Collaboration Agreement, Antibody | Collaboration revenue | Reimbursement for manufacturing of commercial supplies
Disaggregation of Revenue [Line Items]
Revenues	607.9	613	633.7
Sanofi Collaboration Agreement, Antibody | Collaboration revenue | Other
Disaggregation of Revenue [Line Items]
Revenues	0	0	28.7
Sanofi Collaboration Agreement, Antibody | (R&D expense)/Reduction of R&D expense | Regeneron's obligation for its share of Sanofi R&D expenses, net of reimbursement of R&D expenses
Disaggregation of Revenue [Line Items]
Revenues	(46.8)	(83.7)	43
Sanofi Collaboration Agreement, Antibody | Reduction of SG&A expense | Reimbursement of commercialization-related expenses
Disaggregation of Revenue [Line Items]
Revenues	655.4	534.4	437.4
Sanofi Collaboration Agreement, Immuno-oncology | Collaboration revenue | Regeneron's share of profits
Disaggregation of Revenue [Line Items]
Revenues	0	0	6.7
Sanofi Collaboration Agreement, Immuno-oncology | Collaboration revenue | Reimbursement for manufacturing of commercial supplies
Disaggregation of Revenue [Line Items]
Revenues	0	0	4.6
Sanofi Collaboration Agreement, Immuno-oncology | (R&D expense)/Reduction of R&D expense | Reimbursement of R&D expenses
Disaggregation of Revenue [Line Items]
Revenues	0	0	42.7
Sanofi Collaboration Agreement, Immuno-oncology | Reduction of SG&A expense | Regeneron's obligation for its share of Sanofi R&D expenses, net of reimbursement of R&D expenses
Disaggregation of Revenue [Line Items]
Revenues	0	0	21.5
Sanofi Collaboration Agreement, Immuno-oncology | Cost of goods sold | Regeneron's obligation for Sanofi's share of Libtayo U.S. gross profits
Disaggregation of Revenue [Line Items]
Revenues	0	0	(70.1)
Sanofi Collaboration Agreement, Immuno-oncology | Other operating income | Amounts recognized in connection with up-front payments received
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ 0	$ 35.1

Collaboration, License, and O_4

Collaboration, License, and Other Agreements - Sanofi, Antibody Narrative (Details) $ in Millions			12 Months Ended
	Jul. 01, 2022	Jun. 30, 2022	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) milestone
Disaggregation of Revenue [Line Items]
Revenues			$ 14,202	$ 13,117.2	$ 12,172.9
Sanofi Collaboration Agreement, Antibody
Disaggregation of Revenue [Line Items]
Percentage of quarterly profits require to be paid for reimbursement of development costs			10%
Percentage of share of profits used to reimburse collaborating party for trial costs	20%	10%
Contingent reimbursement obligation			$ 1,635
Starting share of profits outside the United States, based on sales, for collaborating party			65%
Starting share of profits outside the United States, based on sales, for company			35%
Ending share of profits outside the United States, based on sales, for collaborating party			55%
Ending share of profits outside the United States, based on sales, for company			45%
Number of sales-based milestones | milestone					2
Sanofi Collaboration Agreement, Antibody | Sales Milestone Five
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, variable consideration amount				50
Levels of twelve month sales at which sales milestone payments would be received				$ 3,000
Period for achieving sales target for milestone payment, rolling basis				12 months
Sanofi Collaboration Agreement, Antibody | Third Milestone
Disaggregation of Revenue [Line Items]
Levels of twelve month sales at which sales milestone payments would be received					$ 2,000
Period for achieving sales target for milestone payment, rolling basis					12 months
Revenues					$ 50
Sanofi Collaboration Agreement, Antibody | Sales Milestone Four
Disaggregation of Revenue [Line Items]
Levels of twelve month sales at which sales milestone payments would be received					$ 2,500
Period for achieving sales target for milestone payment, rolling basis					12 months
Revenues					$ 50
Sanofi Collaboration Agreement, Antibody | Minimum
Disaggregation of Revenue [Line Items]
Percentage of trial costs required to be funded by collaborating party			80%
Percentage of quarterly profits require to be paid for reimbursement of development costs			30%
Sanofi Collaboration Agreement, Antibody | Maximum
Disaggregation of Revenue [Line Items]
Percentage of trial costs required to be funded by collaborating party			100%
Percentage of quarterly profits require to be paid for reimbursement of development costs			50%

Collaboration, License, and O_5

Collaboration, License, and Other Agreements - Schedule of Accounts Receivable and Deferred Revenue Information, Antibody Collaboration (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Accounts receivable, net	$ 6,211.9	$ 5,667.3
Sanofi Collaboration Agreement, Antibody
Disaggregation of Revenue [Line Items]
Accounts receivable, net	1,216.2	1,029.1
Deferred revenue	$ 571.7	$ 427.7

Collaboration, License, and O_6

Collaboration, License, and Other Agreements - Sanofi, Immuno-Oncology Narrative (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues		$ 14,202	$ 13,117.2	$ 12,172.9
Sanofi
Disaggregation of Revenue [Line Items]
Up-front payment to collaborating party	$ 900
Sanofi Collaboration Agreement, Immuno-oncology
Disaggregation of Revenue [Line Items]
Royalty payment to collaborating party, percentage of net product sales		11%
Sanofi Collaboration Agreement, Immuno-oncology | Sanofi | Sales-Based Milestones
Disaggregation of Revenue [Line Items]
Revenues	100
Sanofi Collaboration Agreement, Immuno-oncology | Sanofi | Regulatory Milestone
Disaggregation of Revenue [Line Items]
Up-front payment to collaborating party	100
Sanofi Collaboration Agreement, Immuno-oncology | Sanofi | Sales-Based Milestone One
Disaggregation of Revenue [Line Items]
Revenues	$ 65
Sanofi Collaboration Agreement, Immuno-oncology | Sanofi | Sales-Based Milestone Two
Disaggregation of Revenue [Line Items]
Revenues			$ 35

Collaboration, License, and O_7

Collaboration, License, and Other Agreements - Bayer Narrative (Details) - Bayer $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)
Disaggregation of Revenue [Line Items]
Percentage of repayment of development balance out of profits	50%
Contingent reimbursement obligation	$ 315

Collaboration, License, and O_8

Collaboration, License, and Other Agreements - Schedule of Collaboration Revenue Earned From Bayer (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 14,202	$ 13,117.2	$ 12,172.9
Bayer | Outside United States | Collaboration revenue | Regeneron's share of profits
Disaggregation of Revenue [Line Items]
Revenues	1,403.3	1,376.4	1,317.4
Bayer | Outside United States | Collaboration revenue | Reimbursement for manufacturing of ex-U.S. commercial supplies
Disaggregation of Revenue [Line Items]
Revenues	95.7	111.1	91.4
Bayer | Outside United States | Collaboration revenue | One-time payment in connection with change in Japan arrangement
Disaggregation of Revenue [Line Items]
Revenues	0	0	21.9
Bayer | Outside United States | (R&D expense)/Reduction of R&D expense | Regeneron's obligation for its share of Bayer R&D expenses, net of reimbursement of R&D expenses
Disaggregation of Revenue [Line Items]
Revenues	$ (48.5)	$ (44)	$ 16.7

Collaboration, License, and O_9

Collaboration, License, and Other Agreements - Schedule of Contract Balances, Bayer Collaborative (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Accounts receivable, net	$ 6,211.9	$ 5,667.3
Bayer
Disaggregation of Revenue [Line Items]
Accounts receivable, net	349.9	381.7
Deferred revenue	$ 216.3	$ 138.2

Collaboration, License, and _10

Collaboration, License, and Other Agreements - Amounts Recognized in Statement of Operations with Roche (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 14,202	$ 13,117.2	$ 12,172.9
Roche Collaboration Agreement | Regeneron's share of profits | Collaboration revenue
Disaggregation of Revenue [Line Items]
Revenues	1.4	224.3	627.3
Roche Collaboration Agreement | Other | Collaboration revenue
Disaggregation of Revenue [Line Items]
Revenues	$ 0	$ (13.3)	$ 0

Collaboration, License, and _11

Collaboration, License, and Other Agreements - Other Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Acquired in-process research and development	$ 101	$ 186.1	$ 255.1
Sonoma Biotherapeutics, Inc.
Disaggregation of Revenue [Line Items]
Acquired in-process research and development	$ 45	45
Alnylam Pharmaceuticals, Inc
Disaggregation of Revenue [Line Items]
Acquired in-process research and development		100
Intellia Therapeutics, Inc.
Disaggregation of Revenue [Line Items]
Acquired in-process research and development		30
Checkmate Pharmaceuticals, Inc.
Disaggregation of Revenue [Line Items]
Acquired in-process research and development			195
Agreements with Royalty Provisions
Disaggregation of Revenue [Line Items]
Royalty rate minimum	0.50%
Royalty rate maximum	12%
Royalty expense, net of reimbursements from collaborators	$ 82.9	$ 117.6	$ 84.5
Libtayo | Sanofi Collaboration Agreement, Immuno-oncology | Through December 31, 2023
Disaggregation of Revenue [Line Items]
Percentage of royalties to be paid				8%
Libtayo | Sanofi Collaboration Agreement, Immuno-oncology | January 1, 2024 Through December 31, 2026
Disaggregation of Revenue [Line Items]
Percentage of royalties to be paid				2.50%

Marketable Securities - Schedul

Marketable Securities - Schedule of Investments in Available For Sale Debt Securities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	$ 14,338	$ 12,636
Unrealized Gains	30.1	13.7
Unrealized Losses	(39)	(115.8)
Fair Value	14,329.1	12,533.9
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	8,226.9	6,492.5
Unrealized Gains	25.1	10.4
Unrealized Losses	(31.4)	(104.9)
Fair Value	8,220.6	6,398
U.S. government and government agency obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	4,820.5	4,839.6
Unrealized Gains	3.4	2.4
Unrealized Losses	(6.9)	(8.6)
Fair Value	4,817	4,833.4
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	548.3	636.8
Unrealized Gains	0.4	0.2
Unrealized Losses	0	(0.2)
Fair Value	548.7	636.8
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	380.6	520.8
Unrealized Gains	0.5	0.6
Unrealized Losses	0	0
Fair Value	381.1	521.4
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	279	88.2
Unrealized Gains	0.6	0.1
Unrealized Losses	(0.3)	(1.2)
Fair Value	279.3	87.1
Sovereign bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost Basis	82.7	58.1
Unrealized Gains	0.1	0
Unrealized Losses	(0.4)	(0.9)
Fair Value	$ 82.4	$ 57.2

Marketable Securities - Sched_2

Marketable Securities - Schedule of Debt Securities Based on Contractual Maturity Dates (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Maturities within one year	$ 6,524.3	$ 8,114.8
Maturities after one year through five years	7,804.8	4,414.5
Maturities after five years	0	4.6
Total	$ 14,329.1	$ 12,533.9

Marketable Securities - Sched_3

Marketable Securities - Schedule of Fair Value and Unrealized Losses of Debt Securities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Fair Value - Less than 12 Months	$ 12,179.8	$ 7,854.9
Unrealized Loss - Less than 12 months	(21)	(9)
Fair Value - 12 Months or Greater	1,219.5	4,157.5
Unrealized Loss - 12 Months or Greater	(18)	(106.8)
Fair Value - Total	13,399.3	12,012.4
Unrealized Loss - Total	(39)	(115.8)
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value - Less than 12 Months	7,175.8	2,363.3
Unrealized Loss - Less than 12 months	(14.2)	(2.4)
Fair Value - 12 Months or Greater	1,044.8	4,034.7
Unrealized Loss - 12 Months or Greater	(17.2)	(102.5)
Fair Value - Total	8,220.6	6,398
Unrealized Loss - Total	(31.4)	(104.9)
U.S. government and government agency obligations
Debt Securities, Available-for-sale [Line Items]
Fair Value - Less than 12 Months	4,675.3	4,780.6
Unrealized Loss - Less than 12 months	(6.2)	(6)
Fair Value - 12 Months or Greater	141.7	52.7
Unrealized Loss - 12 Months or Greater	(0.7)	(2.6)
Fair Value - Total	4,817	4,833.3
Unrealized Loss - Total	(6.9)	(8.6)
Sovereign bonds
Debt Securities, Available-for-sale [Line Items]
Fair Value - Less than 12 Months	63.3	12.4
Unrealized Loss - Less than 12 months	(0.3)	(0.1)
Fair Value - 12 Months or Greater	19.1	44.8
Unrealized Loss - 12 Months or Greater	(0.1)	(0.8)
Fair Value - Total	82.4	57.2
Unrealized Loss - Total	(0.4)	(0.9)
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Fair Value - Less than 12 Months		636.8
Unrealized Loss - Less than 12 months		(0.2)
Fair Value - 12 Months or Greater		0
Unrealized Loss - 12 Months or Greater		0
Fair Value - Total		636.8
Unrealized Loss - Total		(0.2)
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Fair Value - Less than 12 Months	265.4	61.8
Unrealized Loss - Less than 12 months	(0.3)	(0.3)
Fair Value - 12 Months or Greater	13.9	25.3
Unrealized Loss - 12 Months or Greater	0	(0.9)
Fair Value - Total	279.3	87.1
Unrealized Loss - Total	$ (0.3)	$ (1.2)

Marketable Securities - Narrati

Marketable Securities - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Investments, Debt and Equity Securities [Abstract]
Interest income	$ 711.4	$ 495.9	$ 160.1

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Assets:
Available-for-sale debt securities	$ 14,329.1	$ 12,533.9
Corporate bonds
Assets:
Available-for-sale debt securities	8,220.6	6,398
U.S. government and government agency obligations
Assets:
Available-for-sale debt securities	4,817	4,833.4
Commercial paper
Assets:
Available-for-sale debt securities	548.7	636.8
Certificates of deposit
Assets:
Available-for-sale debt securities	381.1	521.4
Asset-backed securities
Assets:
Available-for-sale debt securities	279.3	87.1
Sovereign bonds
Assets:
Available-for-sale debt securities	82.4	57.2
Measured on a recurring basis
Assets:
Cash equivalents	1,452.2	928.1
Total assets	16,876.6	14,439.4
Liabilities:
Contingent consideration	52.3	43.7
Measured on a recurring basis | Unrestricted
Assets:
Equity securities	1,052.1	864.5
Measured on a recurring basis | Restricted
Assets:
Equity securities	43.2	112.9
Measured on a recurring basis | Corporate bonds
Assets:
Available-for-sale debt securities	8,220.6	6,398
Measured on a recurring basis | U.S. government and government agency obligations
Assets:
Available-for-sale debt securities	4,817	4,833.4
Measured on a recurring basis | Commercial paper
Assets:
Available-for-sale debt securities	548.7	636.8
Measured on a recurring basis | Certificates of deposit
Assets:
Available-for-sale debt securities	381.1	521.4
Measured on a recurring basis | Asset-backed securities
Assets:
Available-for-sale debt securities	279.3	87.1
Measured on a recurring basis | Sovereign bonds
Assets:
Available-for-sale debt securities	82.4	57.2
Measured on a recurring basis | Level 1
Assets:
Cash equivalents	1,264.2	6.4
Total assets	2,359.5	983.8
Liabilities:
Contingent consideration	0	0
Measured on a recurring basis | Level 1 | Unrestricted
Assets:
Equity securities	1,052.1	864.5
Measured on a recurring basis | Level 1 | Restricted
Assets:
Equity securities	43.2	112.9
Measured on a recurring basis | Level 1 | Corporate bonds
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 1 | U.S. government and government agency obligations
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 1 | Commercial paper
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 1 | Certificates of deposit
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 1 | Asset-backed securities
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 1 | Sovereign bonds
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 2
Assets:
Cash equivalents	188	921.7
Total assets	14,517.1	13,455.6
Liabilities:
Contingent consideration	0	0
Measured on a recurring basis | Level 2 | Unrestricted
Assets:
Equity securities	0	0
Measured on a recurring basis | Level 2 | Restricted
Assets:
Equity securities	0	0
Measured on a recurring basis | Level 2 | Corporate bonds
Assets:
Available-for-sale debt securities	8,220.6	6,398
Measured on a recurring basis | Level 2 | U.S. government and government agency obligations
Assets:
Available-for-sale debt securities	4,817	4,833.4
Measured on a recurring basis | Level 2 | Commercial paper
Assets:
Available-for-sale debt securities	548.7	636.8
Measured on a recurring basis | Level 2 | Certificates of deposit
Assets:
Available-for-sale debt securities	381.1	521.4
Measured on a recurring basis | Level 2 | Asset-backed securities
Assets:
Available-for-sale debt securities	279.3	87.1
Measured on a recurring basis | Level 2 | Sovereign bonds
Assets:
Available-for-sale debt securities	82.4	57.2
Measured on a recurring basis | Level 3
Assets:
Cash equivalents	0	0
Total assets	0	0
Liabilities:
Contingent consideration	52.3	43.7
Measured on a recurring basis | Level 3 | Unrestricted
Assets:
Equity securities	0	0
Measured on a recurring basis | Level 3 | Restricted
Assets:
Equity securities	0	0
Measured on a recurring basis | Level 3 | Corporate bonds
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 3 | U.S. government and government agency obligations
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 3 | Commercial paper
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 3 | Certificates of deposit
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 3 | Asset-backed securities
Assets:
Available-for-sale debt securities	0	0
Measured on a recurring basis | Level 3 | Sovereign bonds
Assets:
Available-for-sale debt securities	$ 0	$ 0

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities owned not readily marketable	$ 159.8	$ 74.3
Net unrealized gains (losses)	117.7	(237.8)	$ (39.8)
Write-down in other income (expense)		29
Level 3 | Measured on a recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity investments	52	0
Level 2 | Measured on a recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, fair value	$ 1,484	$ 1,528

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Inventory Disclosure [Abstract]
Raw materials	$ 879.5	$ 789.3
Work-in-process	1,342.3	1,121.8
Finished goods	139.8	147.3
Deferred costs	725.7	522.1
Total Inventories	$ 3,087.3	$ 2,580.5

Inventories - Narrative (Detail

Inventories - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Inventory Disclosure [Abstract]
Inventory write-downs and reserves	$ 126.3	$ 102.3	$ 258.7

Property, Plant, and Equipmen_2

Property, Plant, and Equipment - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 6,886.6	$ 6,125.2
Accumulated depreciation and amortization	(2,286.9)	(1,978.8)
Property, plant, and equipment, net	4,599.7	4,146.4
Building and improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	2,573.2	2,423.1
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	154.5	133.9
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	1,494.5	1,384.5
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	450.8	389.7
Furniture, office equipment, and other
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	203.8	165.9
Land
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	288.2	283.1
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, gross	$ 1,721.6	$ 1,345

Property, Plant, and Equipmen_3

Property, Plant, and Equipment - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 354.1	$ 328.8	$ 303.9
Property, plant, and equipment, net	4,599.7	4,146.4
United States
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, net	3,884	3,375
Rest Of World
Property, Plant and Equipment [Line Items]
Property, plant, and equipment, net	$ 715.9	$ 771.4

Intangible Assets - Schedule of

Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible assets, net	$ 1,148.6	$ 1,038.6
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	1,410.5	1,171.6
Accumulated Amortization	(261.9)	(133)
Acquired in-process research and development
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 52.8	42.5
Acquired product rights - Libtayo
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life (in years)	13 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 1,347.7	1,119.1
Accumulated Amortization	(254.3)	(126.7)
Net Carrying Amount	$ 1,093.4	992.4
Other intangibles
Finite-Lived Intangible Assets [Line Items]
Estimated Useful Life (in years)	8 years
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 10	10
Accumulated Amortization	(7.6)	(6.3)
Net Carrying Amount	$ 2.4	$ 3.7

Intangible Assets - Narrative (

Intangible Assets - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Indefinite-Lived Intangible Assets [Line Items]
Amortization expense on intangible assets	$ 128.9	$ 92.2	$ 37.6
Finite-lived intangible asset, expected amortization, year one	102
Finite-lived intangible asset, expected amortization, year two	102
Finite-lived intangible asset, expected amortization, year three	102
Finite-lived intangible asset, expected amortization, year four	102
Finite-lived intangible asset, expected amortization, year five	102
Acquired in-process research and development
Indefinite-Lived Intangible Assets [Line Items]
Indefinite-lived intangible assets	$ 52.8	$ 42.5

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Accrued payroll and related costs	$ 640.9	$ 618.2
Accrued clinical expenses	315.7	292.2
Accrued sales-related costs	786.2	780.8
Income tax-related costs	213.2	11.7
Other accrued expenses and liabilities	571.1	655
Accrued expenses and other current liabilities	$ 2,527.1	$ 2,357.9

Debt - Summary of Issued Senior

Debt - Summary of Issued Senior Unsecured Notes (Details) - Senior unsecured notes - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Long-term debt	$ 1,984.4	$ 1,982.9
1.750% Senior Notes due September 2030
Debt Instrument [Line Items]
Interest rate	1.75%
Long-term debt	$ 1,243.3	1,242.2
2.800% Senior Notes due September 2050
Debt Instrument [Line Items]
Interest rate	2.80%
Long-term debt	$ 741.1	$ 740.7

Debt - Narrative (Details)

Debt - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Line of credit | Senior unsecured revolving credit facility
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 750,000,000
Line of credit facility, expiration period	5 years
Line of credit facility, increase limit	$ 500,000,000
Borrowings outstanding	0
Line of credit | Letters of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	50,000,000
Senior unsecured notes
Debt Instrument [Line Items]
Interest expense	$ 44,400,000	$ 44,400,000	$ 44,400,000

Leases - Leases Narrative (Deta

Leases - Leases Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2024	Mar. 27, 2023	Mar. 31, 2017
Lessee, Lease, Description [Line Items]
Finance lease, liability	$ 720
Finance lease, renewal term		5 years
Laboratory and Office Facilities
Lessee, Lease, Description [Line Items]
Finance lease, liability			$ 720

Leases - Amounts recognized in

Leases - Amounts recognized in Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Assets:
Finance lease right-of-use assets	$ 591.2	$ 605.7
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Property, plant, and equipment, net	Property, plant, and equipment, net
Operating lease right-of-use assets	$ 217.4	$ 78
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets	Other noncurrent assets
Total lease assets	$ 808.6	$ 683.7
Liabilities:
Finance lease liabilities	720	720
Operating lease liabilities - current	$ 30.3	$ 19
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Operating lease liabilities - noncurrent	$ 204.1	$ 68.7
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other noncurrent liabilities	Other noncurrent liabilities
Total lease liability	$ 954.4	$ 807.7
Accumulated amortization of right-of-use assets	148.4	133.9
Operating lease, right-of-use asset, accumulated amortization	$ 78.4	$ 44.6

Leases - Finance lease costs (D

Leases - Finance lease costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Operating lease costs	$ 36.5	$ 19.2	$ 12.4
Amortization of finance lease right-of-use assets	14.5	14.5	14.5
Interest on finance lease liabilities	46.1	45	21.6
Total finance lease costs	60.6	59.5	36.1
Total lease cost	$ 97.1	$ 78.7	$ 48.5

Leases - Other information rela

Leases - Other information related to finance lease (Details)	Dec. 31, 2024	Dec. 31, 2023
Weighted-average remaining lease term (in years):
Finance leases	2 years 2 months 12 days	3 years 2 months 12 days
Operating leases	7 years 2 months 12 days	7 years 4 months 24 days
Weighted-average discount rate:
Finance leases	5.03%	5.08%
Operating leases	5.52%	5.38%

Leases - Supplemental cash flow

Leases - Supplemental cash flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Leases [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities (included within cash flows from operating activities)	$ 41.4	$ 22.5	$ 7.7
Right-of-use assets obtained in exchange for operating lease liabilities	$ 188.1	$ 31.9	$ 35.1

Leases - Analysis of lease liab

Leases - Analysis of lease liability maturities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Finance Leases
2024	$ 38.6
2025	36.8
2026	729.1
2027	0
2028	0
Thereafter	0
Total undiscounted lease payments	804.5
Imputed interest	(84.5)
Total lease liabilities	720
Operating Leases
2024	43.1
2025	44.8
2026	42.6
2027	33.2
2028	30.3
Thereafter	96.9
Total undiscounted lease payments	290.9
Imputed interest	(56.5)
Total lease liabilities	234.4
Total
2024	81.7
2025	81.6
2026	771.7
2027	33.2
2028	30.3
2029	96.9
Total undiscounted lease payments	1,095.4
Imputed interest	(141)
Total lease liabilities	$ 954.4	$ 807.7

Stockholders' Equity - Narrativ

Stockholders' Equity - Narrative (Details)	1 Months Ended	12 Months Ended	20 Months Ended	21 Months Ended
	Feb. 28, 2025 $ / shares	Dec. 31, 2024 USD ($) vote $ / shares shares	Jun. 30, 2023 USD ($)	Sep. 30, 2024 USD ($)	Feb. 05, 2025 USD ($)	Apr. 30, 2024 USD ($)	Dec. 31, 2023 $ / shares shares	Jan. 31, 2023 USD ($)	Nov. 30, 2021 USD ($)
Class of Stock [Line Items]
Preferred Stock, shares authorized (in shares) | shares		30,000,000					30,000,000
Remaining authorized repurchase amount		$ 1,917,000,000
Forecast
Class of Stock [Line Items]
Common stock, dividend, declared (in dollars per share) | $ / shares	$ 0.88
Share Repurchase Program, November 2021
Class of Stock [Line Items]
Stock repurchase program, authorized amount									$ 3,000,000,000
Cost of stock repurchased			$ 3,000,000,000
Share Repurchase Program, January 2023
Class of Stock [Line Items]
Stock repurchase program, authorized amount								$ 3,000,000,000
Cost of stock repurchased				$ 3,000,000,000
Share Repurchase Program, April 2024
Class of Stock [Line Items]
Stock repurchase program, authorized amount						$ 3,000,000,000
Share Repurchase Program, February 2025 | Subsequent Event
Class of Stock [Line Items]
Stock repurchase program, authorized amount					$ 3,000,000,000
Class A Stock
Class of Stock [Line Items]
Common Stock, shares authorized (in shares) | shares		40,000,000					40,000,000
Common Stock, par value (in dollars per share) | $ / shares		$ 0.001					$ 0.001
Number of votes per share | vote		10
Common Stock
Class of Stock [Line Items]
Common Stock, shares authorized (in shares) | shares		320,000,000					320,000,000
Common Stock, par value (in dollars per share) | $ / shares		$ 0.001					$ 0.001
Number of votes per share | vote		1

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Repurchased Shares (Details) - Share Repurchase Programs - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity, Class of Treasury Stock [Line Items]
Number of shares (in shares)	2.8	2.9	3.3
Total cost of shares	$ 2,613.9	$ 2,214.6	$ 2,099.8

Long-Term Incentive Plans - Nar

Long-Term Incentive Plans - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Maximum term of awards	10 years
Total intrinsic value - of stock options exercised	$ 1,682	$ 1,096	$ 1,214
Expected dividend yield	0%	0%	0%
Non-performance based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock-based compensation expense	$ 376	$ 357.1	$ 341.9
Unrecognized stock-based compensation cost, net of estimated forfeitures	$ 626.7
Weighted average period for recognition of total unrecognized compensation expense (in years)	1 year 10 months 24 days
Restricted stock awards and restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock-based compensation expense	$ 554.7	$ 475.9	331.1
Unrecognized stock-based compensation cost, net of estimated forfeitures	$ 1,219
Weighted average period for recognition of total unrecognized compensation expense (in years)	2 years 3 months 18 days
Awards outstanding (in shares)	2,500	2,300
Weighted-average grant date fair value of awards outstanding (in USD per share)	$ 760.35	$ 705.37
Granted (in shares)	1,000
Vested (in shares)	700
Awards forfeited (in shares)	100
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-cash stock-based compensation expense	$ 52.1	$ 52.1	$ 52.1
Unrecognized stock-based compensation cost, net of estimated forfeitures	$ 52
Weighted average period for recognition of total unrecognized compensation expense (in years)	1 year
Expected dividend yield			0%
Awards outstanding (in shares)	1,400	1,400
Weighted-average grant date fair value of awards outstanding (in USD per share)	$ 247.91	$ 247.91
Granted (in shares)	0
Vested (in shares)	0
Awards forfeited (in shares)	0
Cancelled (in shares)	0
Performance-based stock options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Performance-based stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	6 years
Amended & Restated Long-Term Incentive Plan 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance (in shares)	22,300
Number of shares available for future grants (in shares)	13,100

Long-Term Incentive Plans - Sum

Long-Term Incentive Plans - Summary of transactions involving stock option awards (Details) - Stock options - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Number of Shares (In millions)
Outstanding at beginning of period (in shares)	14.2
Granted (in shares)	1.9	1.6	2
Forfeited (in shares)	(0.2)
Exercised (in shares)	(3.2)
Outstanding at end of period (in shares)	12.7	14.2
Vested and expected to vest (in shares)	12.3
Exercisable (in shares)	8.3
Weighted-Average Exercise Price
Outstanding at beginning of period (in dollars per share)	$ 534.13
Granted (in dollars per share)	786.79	$ 835.91	$ 705.02
Forfeited (in dollars per share)	698.92
Exercised (in dollars per share)	454.70
Outstanding at end of period (in dollars per share)	588.47	$ 534.13
Vested and expected to vest (in dollars per share)	582.36
Exercisable (in dollars per share)	$ 495.19
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (in years) - outstanding	6 years 1 month 6 days
Weighted average remaining contractual term - vested and expected to vest	6 years
Weighted average remaining contractual term - exercisable	4 years 8 months 12 days
Intrinsic value - outstanding	$ 1,891
Intrinsic value - vested and expected to vest	1,888.5
Intrinsic value - exercisable	$ 1,834.8

Long-Term Incentive Plans - S_2

Long-Term Incentive Plans - Summary of weighted-average exercise prices and weighted-average grant-date fair values of options issued (Details) - Stock options - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Options Granted (in shares)	1.9	1.6	2
Weighted-Average Exercise Price (in dollars per share)	$ 786.79	$ 835.91	$ 705.02
Weighted-Average Fair Value (in dollars per share)	$ 235.32	$ 264.37	$ 220.88

Long-Term Incentive Plans - S_3

Long-Term Incentive Plans - Summary of weighted-average values of assumptions used in computing fair value of option grants (Details) - Stock options	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	25%	26%	28%
Expected lives from grant date	5 years	5 years 1 month 6 days	5 years 2 months 12 days
Expected dividend yield	0%	0%	0%
Risk-free interest rate	4.11%	4.29%	3.50%

Long-Term Incentive Plans - S_4

Long-Term Incentive Plans - Summary of activity related to restricted stock awards (Details) - Restricted stock awards and restricted stock units shares in Millions	12 Months Ended
	Dec. 31, 2024 $ / shares shares
Number of Shares/Units (In millions)
Beginning balance (in shares) | shares	2.3
Granted (in shares) | shares	1
Vested (in shares) | shares	(0.7)
Forfeited (in shares) | shares	(0.1)
Ending balance (in shares) | shares	2.5
Weighted-Average Grant Date Fair Value
Beginning balance (in dollars of shares) | $ / shares	$ 705.37
Granted (in dollars of shares) | $ / shares	787.15
Vested (in dollars of shares) | $ / shares	617.50
Forfeited (in dollars of shares) | $ / shares	704.57
Ending balance (in dollars of shares) | $ / shares	$ 760.35

Long-Term Incentive Plans - S_5

Long-Term Incentive Plans - Summary of weighted-average values of assumptions used in computing fair value of performance-based options (Details) - Performance-based stock options	12 Months Ended
	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	32%
Expected dividend yield	0%
Risk-free interest rate	3.30%

Employee Savings Plans (Details

Employee Savings Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Retirement Benefits [Abstract]
Employer contribution expense to 401(k) Savings Plan	$ 90.2	$ 84.7	$ 67.6

Income Taxes - Schedule of inco

Income Taxes - Schedule of income before income tax (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income before income taxes, United States	$ (411.3)	$ (362.3)	$ 839.9
Income before income taxes, Foreign	5,191.2	4,561.6	4,018.9
Income before income taxes	$ 4,779.9	$ 4,199.3	$ 4,858.8

Income Taxes - Schedule of comp

Income Taxes - Schedule of components of income tax expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Current:
Federal	$ 1,092.6	$ 667.9	$ 968.5
State	(11.1)	7.7	7.4
Foreign	43.1	407.9	290.9
Total current tax expense	1,124.6	1,083.5	1,266.8
Deferred:
Federal	(935.5)	(834.5)	(797.7)
State	(4.9)	(6.5)	(2.7)
Foreign	183.1	3.2	54
Total deferred tax benefit	(757.3)	(837.8)	(746.4)
Total income tax expense (benefit)	$ 367.3	$ 245.7	$ 520.4

Income Taxes - Schedule of effe

Income Taxes - Schedule of effective income tax rate reconciliation (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
U.S. federal statutory tax rate	21%	21%	21%
Stock-based compensation	(4.90%)	(4.60%)	(2.90%)
Taxation of non-U.S. operations	(4.00%)	(6.60%)	(5.50%)
Income tax credits	(3.50%)	(3.20%)	(2.00%)
Foreign-derived intangible income deduction	(0.80%)	(0.30%)	(1.00%)
Other permanent differences	(0.10%)	(0.40%)	1.10%
Effective income tax rate	7.70%	5.90%	10.70%

Income Taxes - Schedule of defe

Income Taxes - Schedule of deferred tax assets and liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Capitalized research and development expenses	$ 2,530.2	$ 1,728.2
Deferred compensation	419.7	413.6
Accrued expenses	185	214.1
Fixed assets and intangible assets	145.1	154.8
Tax attribute carryforwards	84.1	88.7
Other	43	26.4
Total deferred tax assets	3,407.1	2,625.8
Deferred tax liabilities:
Unrealized gains on investments	(93)	(50.4)
Net deferred tax assets	$ 3,314.1	$ 2,575.4

Income Taxes - Schedule of unre

Income Taxes - Schedule of unrecognized tax benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Unrecognized Tax Benefits [Roll Forward]
Balance as of January 1	$ 696.4	$ 542.8	$ 410.9
Gross increases related to current year tax positions	353.5	153.4	136.9
Gross increases related to prior year tax positions	264.8	3.2
Gross decreases related to prior year tax positions			(5)
Gross decreases due to settlements and lapse of statutes of limitations	(1)	(3)	0
Balance as of December 31	$ 1,313.7	$ 696.4	$ 542.8

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Interest expense related to unrecognized tax benefits	$ 165.4	$ 77.2	$ 38
Expected payment, unrecognized tax benefits	120
Unrecognized tax benefits that would impact effective tax rate	$ 635.4	$ 442.5	$ 373.7

Legal Matters (Details)

Legal Matters (Details)	Jan. 22, 2025 complaint	Jul. 16, 2020 claim
Subsequent Event
Loss Contingencies [Line Items]
Number of shareholder derivative complaints filed | complaint	2
'631 Patent
Loss Contingencies [Line Items]
Number of IPR filed | claim		2

Net Income Per Share - Schedule

Net Income Per Share - Schedule of Basic and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income - basic and diluted	$ 4,412.6	$ 3,953.6	$ 4,338.4
Weighted average shares outstanding - basic (in shares)	107.9	106.7	107.1
Effect of dilutive securities:
Weighted average shares - diluted (in shares)	115.1	113.7	113.5
Net income per share - basic (in dollars per share)	$ 40.90	$ 37.05	$ 40.51
Net income per share - diluted (in dollars per share)	$ 38.34	$ 34.77	$ 38.22
Stock options
Effect of dilutive securities:
Effect of dilutive securities (in shares)	4.8	4.9	4.9
Restricted stock awards and restricted stock units
Effect of dilutive securities:
Effect of dilutive securities (in shares)	2.4	2.1	1.5

Net Income Per Share - Schedu_2

Net Income Per Share - Schedule of Antidilutive Securities Excluded From Computation (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of shares (in shares)	1.6	1.8	2.3

Statement of Cash Flows - Sched

Statement of Cash Flows - Schedule of Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 2,488.2	$ 2,730	$ 3,105.9
Restricted cash included in Other current assets	0.8	0	0
Restricted cash included in Other noncurrent assets	0	7.8	13.5
Total cash, cash equivalents, and restricted cash shown in the Consolidated Statements of Cash Flows	$ 2,489	$ 2,737.8	$ 3,119.4	$ 2,898.1

Statement of Cash Flows - Summa

Statement of Cash Flows - Summary of Non-Cash Investing and Financing Activities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash and Cash Equivalents [Abstract]
Accrued capital expenditures	$ 151.6	$ 75.4	$ 70.8
Accrued contingent consideration in connection with acquisitions	$ 62.7	$ 71.6	$ 135.5