Interim Financial Statements (Notes)	6 Months Ended
Jun. 30, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Interim Financial Statements	Interim Financial Statements The interim Condensed Consolidated Financial Statements of Regeneron Pharmaceuticals, Inc. and its subsidiaries ("Regeneron" or the "Company") have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company's financial position, results of operations, and cash flows in conformity with accounting principles generally accepted in the United States of America. In the opinion of management, these financial statements reflect all normal recurring adjustments and accruals necessary for a fair statement of the Company's financial position, results of operations, and cash flows for such periods. The results of operations for any interim period are not necessarily indicative of the results for the full year. The December 31, 2016 Condensed Consolidated Balance Sheet data were derived from audited financial statements, but do not include all disclosures required by accounting principles generally accepted in the United States of America. These financial statements should be read in conjunction with the financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016. Certain reclassifications have been made to prior period amounts to conform with the current period's presentation. During the second quarter of 2017, the Company recorded an out-of-period adjustment to reflect a correction in the Company's accounting for its lease of its Tarrytown, New York facility (see Note 10). The adjustment, which was related to the March 3, 2017 lease transaction, resulted in the recognition of a $30.1 million loss on extinguishment of debt within other expenses and a corresponding decrease to property, plant, and equipment. These were non-cash adjustments, and therefore had no impact on the Company's previously reported operating, investing, financing, or total cash flows in its Statements of Cash Flows. The Company evaluated the impact of these items on prior periods, assessing materiality quantitatively and qualitatively, and concluded that the amounts were not considered to be material to any previously-issued quarterly or annual financial statements, and that the impact of correcting the error in the three and six months ended June 30, 2017 was not material to these financial statements, nor is the adjustment expected to be material to the financial statements for the year ending December 31, 2017.

Interim Financial Statements

The interim Condensed Consolidated Financial Statements of Regeneron Pharmaceuticals, Inc. and its subsidiaries ("Regeneron" or the "Company") have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information and disclosures necessary for a presentation of the Company's financial position, results of operations, and cash flows in conformity with accounting principles generally accepted in the United States of America. In the opinion of management, these financial statements reflect all normal recurring adjustments and accruals necessary for a fair statement of the Company's financial position, results of operations, and cash flows for such periods. The results of operations for any interim period are not necessarily indicative of the results for the full year. The December 31, 2016 Condensed Consolidated Balance Sheet data were derived from audited financial statements, but do not include all disclosures required by accounting principles generally accepted in the United States of America. These financial statements should be read in conjunction with the financial statements and notes thereto contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2016.

Certain reclassifications have been made to prior period amounts to conform with the current period's presentation.

During the second quarter of 2017, the Company recorded an out-of-period adjustment to reflect a correction in the Company's accounting for its lease of its Tarrytown, New York facility (see Note 10). The adjustment, which was related to the March 3, 2017 lease transaction, resulted in the recognition of a $30.1 million loss on extinguishment of debt within other expenses and a corresponding decrease to property, plant, and equipment. These were non-cash adjustments, and therefore had no impact on the Company's previously reported operating, investing, financing, or total cash flows in its Statements of Cash Flows. The Company evaluated the impact of these items on prior periods, assessing materiality quantitatively and qualitatively, and concluded that the amounts were not considered to be material to any previously-issued quarterly or annual financial statements, and that the impact of correcting the error in the three and six months ended June 30, 2017 was not material to these financial statements, nor is the adjustment expected to be material to the financial statements for the year ending December 31, 2017.