| Line Item | Dec 31, 2025 | Dec 31, 2024 | Dec 31, 2023 | Dec 31, 2022 | Dec 31, 2021 | Dec 31, 2020 | Dec 31, 2019 | Dec 31, 2018 | Dec 31, 2017 | Dec 31, 2016 |
|---|---|---|---|---|---|---|---|---|---|---|
| Profit (loss) [abstract] | ||||||||||
| Net sales | ||||||||||
| Other revenues | ||||||||||
| Cost of sales | ||||||||||
| Gross profit | ||||||||||
| Research and development expenses | ||||||||||
| Selling and general expenses | ||||||||||
| Other operating income | ||||||||||
| Other operating expenses | ||||||||||
| Amortization of intangible assets | ||||||||||
| Impairment of intangible assets | ||||||||||
| Fair value remeasurement of contingent consideration | ||||||||||
| Restructuring costs and similar items | ||||||||||
| Other gains and losses, and litigation | ||||||||||
| Operating income | ||||||||||
| Financial expenses | ||||||||||
| Financial income | ||||||||||
| Income before tax and investments accounted for using the equity method | ||||||||||
| Income tax expense | ||||||||||
| Share of profit/(loss) from investments accounted for using the equity method | ||||||||||
| Net income from continuing operations | ||||||||||
| Net income excluding the exchanged/held-for-exchange Animal Health business | ||||||||||
| Net income | ||||||||||
| Net income attributable to non-controlling interests | ||||||||||
| Net income attributable to equity holders of Sanofi |