| Revenue | — | — | — |
| Product revenue, net | 7,213.5a | 7,246.7a | 7,987.8a |
| Revenue from anti-CD20 therapeutic programs | 1,749.9a | 1,689.6a | 1,700.5a |
| Alzheimer's collaboration revenue | 59.9a | 0a | 0a |
| Contract manufacturing, royalty and other revenue | 652.6a | 899.3a | 485.1a |
| Total revenue | 9,675.9a | 9,835.6a | 10,173.4a |
| Cost and expense | — | — | — |
| Cost of sales, excluding amortization and impairment of acquired intangible assets | -2,310.4a | -2,533.4a | -2,278.3a |
| Research and development | -2,041.8a | -2,462a | -2,231.1a |
| Selling, general and administrative | -2,403.7a | -2,549.7a | -2,403.6a |
| Amortization and impairment of acquired intangible assets | -446.7a | -240.6a | -365.9a |
| Collaboration profit sharing/(loss reimbursement) | 254.4a | 218.8a | -7.4a |
| (Gain) loss on fair value remeasurement of contingent consideration | 27.7a | 0a | -209.1a |
| Restructuring charges | -30.2a | -218.8a | -131.1a |
| Gain on sale of priority review voucher, net | -88.6a | 0a | 0a |
| Gain on sale of building, net | 0a | 0a | -503.7a |
| Other (income) expense, net | 343.6a | 315.5a | -108.2a |
| Total cost and expense | -7,769.9a | -8,538.8a | -6,581.6a |
| Income before income tax (benefit) expense and equity in (income) loss of investee, net of tax | 1,906a | 1,296.8a | 3,591.8a |
| Income tax (benefit) expense | -273.8a | -135.3a | -632.8a |
| Equity in (income) loss of investee, net of tax | 0a | 0a | -2.6a |
| Net income | 1,632.2a | 1,161.5a | 2,961.6a |
| Net income (loss) attributable to noncontrolling interests, net of tax | 0a | 0.4a | -85.3a |
| Net income attributable to Biogen Inc. | 1,632.2a | 1,161.1a | 3,046.9a |