Expense incurred by the collaboration
Expense incurred by the collaboration
Expense incurred by the collaboration
Stock Repurchase Program, Authorized Amount
Stock Repurchase Program, Authorized Amount
Hedging Designation [Domain]
Hedging Designation [Domain]
Customer [Domain]
Customer [Domain]
Unrealized gains (losses) on securities available for sale
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Intangible assets
Intangible Assets Excluding Goodwill [Table Text Block]
Intangible assets excluding goodwill.
Litigation
Legal Matters and Contingencies [Text Block]
Statutory rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Technological and Regulatory Success, Probability
Technological and Regulatory Success, Probability
Technological and Regulatory Success, Probability
Trademarks and Trade Names
Trademarks and Trade Names [Member]
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV [Domain]
Net income attributable to Biogen Inc.
Net income attributable to Biogen Inc.
Net Income (Loss) Attributable to Parent
Consolidated Entities [Axis]
Consolidated Entities [Axis]
Operating lease assets
Operating Lease, Right-of-Use Asset
Foreign currency forward contracts that were entered into to hedge forecasted revenue
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]
Marketable securities
Debt Securities, Available-for-sale, Current
Collaboration expense
Employee-related Liabilities, Current
ZINBRYTA
ZINBRYTA [Member]
ZINBRYTA [Member]
Income Statement Location [Axis]
Income Statement Location [Axis]
Accumulated Amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Statistical Measurement [Domain]
Statistical Measurement [Domain]
Payments/Returns Relating To Sales in Prior Year
Payments Returns Applied Against Product Revenue Reserves Relating To Prior Year
Payments/ returns applied against product revenue reserves relating to prior year.
Security Exchange Name
Security Exchange Name
Fair Value
Equity Securities, FV-NI, Current
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Abstract]
Restructuring Type [Axis]
Restructuring Type [Axis]
Denali Therapeutics
Denali Therapeutics Inc [Member]
Denali Therapeutics Inc
Investments and other assets
Other Assets, Noncurrent
Investment, Name [Axis]
Investment, Name [Axis]
Capital contribution from noncontrolling interest
Noncontrolling Interest, Increase (Decrease) Other
Noncontrolling Interest, Increase (Decrease) Other
In-process research and development
In Process Research and Development [Member]
Proceeds from the sales of strategic investments
Proceeds from Sale of Equity Method Investments
SPINRAZA
SPINRAZA [Member]
SPINRAZA [Member]
Inventory
Inventories [Member]
Entity File Number
Entity File Number
Other income (expense), net
Schedule of Other Nonoperating Income (Expense) [Table Text Block]
TYSABRI
TYSABRI product [Member]
TYSABRI product [Member]
Income tax assets and liabilities
Increase (Decrease) in Income Taxes Payable
(Gain) loss on fair value remeasurement of contingent consideration
Contingent consideration
Contingent consideration impairment
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings
Derivative contracts
Foreign Currency Contracts, Liability, Fair Value Disclosure
Marketable debt and equity securities
Debt Securities, Available-for-sale [Table Text Block]
Centers for Medicare and Medicaid Service
Centers for Medicare and Medicaid Service [Member]
Centers for Medicare and Medicaid Service
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]
Biogen's share of pre-tax profits in the U.S. for RITUXAN and GAZYVA
Share Of Co Promotion Profits
Share of co promotion profits.
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Acquisition, Contingent Consideration [Line Items]
Business Acquisition, Contingent Consideration [Line Items]
Schedule of Restructuring Reserve by Type of Cost
Schedule of Restructuring Reserve by Type of Cost [Table Text Block]
Amount remaining under 2019 Share Repurchase Program
Stock Repurchase Program, Remaining Authorized Repurchase Amount
Research and development asset [Domain]
Research and development asset [Domain]
[Domain] for Research and development asset [Axis]
Other current assets
Other Current Assets [Member]
Deferred tax assets, net
Deferred Tax Assets, Net
Components of inventory
Schedule of Inventory, Current [Table Text Block]
Research and development
Research and development
Research and Development Expense [Member]
InnoCare Pharma Limited (InnoCare) Agreement
InnoCare Pharma Limited (InnoCare) Agreement [Member]
InnoCare Pharma Limited (InnoCare) Agreement
Subsequent Events [Abstract]
Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table]
Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table]
Cash Flow Hedging [Member]
Cash Flow Hedging [Member]
Award Type [Domain]
Award Type [Domain]
Share Repurchase Program [Domain]
Share Repurchase Program [Domain]
Contractual adjustments
Contractual Adjustments [Member]
Contractual adjustments.
Local Phone Number
Local Phone Number
ASSETS
Assets [Abstract]
Gains (losses) on net investment hedge
Accumulated Other Comprehensive Income (Loss), Derivative Qualifying as Hedge, Excluded Component, Including Portion Attributable to Noncontrolling Interest [Member]
Accumulated impairment losses related to goodwill
Goodwill, Impaired, Accumulated Impairment Loss
Completed technology
Out Licensed Patents [Member]
Out-licensed patents.
Distributor Two
Distributor Two [Member]
Distributor two.
Adjustments Relating To Prior Years
Adjustments To Product Revenue Reserves Relating To Sales In Prior Years
Adjustments to product revenue reserves relating to sales in prior years.
Percentage of stake in entity
Equity Method Investment, Ownership Percentage Before Additional Purchase Transaction
Equity Method Investment, Ownership Percentage Before Additional Purchase Transaction
Derivative Instruments
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Summary of contractual maturities: available-for-sale securities
Investments Classified by Contractual Maturity Date [Table Text Block]
Decrease in unrecognized tax benefits is reasonably possible
Decrease in Unrecognized Tax Benefits is Reasonably Possible
Research and development
Research and Development Expense (Excluding Acquired in Process Cost)
Research and Development Expense (Excluding Acquired in Process Cost)
Intangible Assets and Goodwill
Goodwill and Intangible Assets Disclosure [Text Block]
Preferred stock, par value $0.001 per share
Preferred Stock, Value, Issued
Currency [Axis]
Currency [Axis]
Market stock units
Market Stock Units [Member]
Market stock units.
Retained earnings
Retained Earnings [Member]
3.625% Senior Notes due 2022
Senior Notes Three Point Six Two Five Percent Due Twenty Twenty Two [Member]
Senior Notes Three Point Six Two Five Percent Due Twenty Twenty Two [Member]
Debt Instrument [Axis]
Debt Instrument [Axis]
Marketable debt securities
Debt Securities, Available-for-sale [Abstract]
Debt instruments, fair value
Debt Instrument, Fair Value Disclosure
Mortgage and other asset backed securities Current
Mortgage And Other Asset Backed Securities Current [Member]
Mortgage and other asset backed securities Current.
Short-term debt securities
Debt Securities [Member]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Neurimmune tax impacts
Effective Tax Rate Reconciliation, NuerImmune Tax Impacts
Effective Tax Rate Reconciliation, NuerImmune Tax Impacts
Share-based compensation expense included in total costs and expenses
Share Based Compensation Expense Included In Costs And Expenses
Share based compensation expense included in costs and expenses.
Discount rate
Business Combination, Contingent Consideration, Liability, Measurement Input
Investments, All Other Investments [Abstract]
Investments, All Other Investments [Abstract]
Inventory, Current [Table]
Inventory, Current [Table]
Accounts receivable
Increase (Decrease) in Accounts Receivable
IMRALDI
IMRALDI [Member]
IMRALDI [Member]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Capitalized share-based compensation costs
Share-based Payment Arrangement, Amount Capitalized
Comprehensive income (loss) attributable to noncontrolling interests, net of tax
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Percentage of revenues from major distributors
Entity Wide Percentage Of Revenue From Major Distributors
Entity wide percentage of revenue from major distributors.
Due to Related Parties
Due to Related Parties
Other Income (Expense), Net
Interest Income (Expense), Net [Abstract]
Operating expense
Operating Expense [Member]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Other income (expense)
Other Nonoperating Income (Expense) [Member]
Basic earnings per share attributable to Biogen Inc.
Earnings Per Share, Basic
Less: Net gains (losses) realized during the period on equity securities
Net gains (losses) realized during the period on equity securities
Equity Securities, FV-NI, Realized Gain (Loss)
Indefinite-lived Intangible Assets, Major Class Name [Domain]
Indefinite-lived Intangible Assets, Major Class Name [Domain]
Unrealized gains (losses) on pension benefit obligation, net of tax
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Investments in Variable Interest Entities [Abstract]
Investments in Variable Interest Entities [Abstract]
Investments In Variable Interest Entities.
Government securities
US Treasury and Government [Member]
Revenues
Revenue from Contract with Customer [Text Block]
Other research and discovery
Other research and discovery [Member]
Other research and discovery [Member]
SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis]
SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis]
Due after one year through five years, amortized cost
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, after Year One Through Five
Revenues by product
Disaggregation of Revenue [Table Text Block]
Due from Related Parties
Due from Related Parties
Plan assets for deferred compensation
Plan Assets For Deferred Compensation Fair Value Disclosure
Fair values as of the balance sheet date of all assets of deferred compensation plans.
Unrealized Gain (Loss) on Derivatives
Unrealized Gain (Loss) on Derivatives
GILTI
Effective Tax Rate Reconciliation, GILTI tax
Effective Tax Rate Reconciliation, GILTI tax
Current Provisions Relating To Sales In Current Year
Current Provisions To Product Revenue Reserves Relating To Sales In Current Year
Current provisions to product revenue reserves relating to sales in current year.
Fumarate
Fumarate [Member]
Fumarate [Member]
Commercial paper
Commercial Paper [Member]
Other
Other Noncash Income (Expense)
Derivative asset, fair value
Derivative Asset, Fair Value, Gross Asset
Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents
Cash Equivalents, at Carrying Value [Abstract]
3.150% Senior Notes due May 1, 2050
3.15% Senior Notes due May 1, 2050 [Member]
3.15% Senior Notes due May 1, 2050 [Member]
Summary of roll forward of the changes in goodwill
Goodwill [Roll Forward]
Summary of the effect of derivatives designated as net investment hedging instruments on our consolidated statement of income
Schedule of Net Investment Hedges in Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Discounts
Reserve for Cash Discounts [Member]
Reserve for Cash Discounts [Member]
Gain (loss) on investments in equity securities
Gain (Loss) on Securities [Table Text Block]
Number of wholesalers
Number of Wholesalers
Number of Wholesalers
Assets:
Assets, Fair Value Disclosure [Abstract]
4.050% Senior Notes due 2025
Senior Notes Four Point Zero Five Percent Due Twenty Twenty Five [Member]
Senior Notes Four Point Zero Five Percent Due Twenty Twenty Five [Member]
Notes payable
Long-term Debt
Total
Assets, Fair Value Disclosure
Quoted Prices in Active Markets (Level 1)
Fair Value, Inputs, Level 1 [Member]
Cash flows from investing activities:
Net Cash Provided by (Used in) Investing Activities [Abstract]
Equity Method Investments, Expected Profit Share
Equity Method Investments, Expected Profit Share
Equity Method Investments, Expected Profit Share
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Abstract]
Entity Small Business
Entity Small Business
Upfront and milestone payments made to collaborative partner
Upfront And Milestone Payments Made To Collaborative Partner
Total upfront and milestone payments made to collaborative partner.
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets [Line Items]
Total liabilities and equity
Liabilities and Equity
Other
Other Accrued Liabilities, Current
Other
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent
Investments, Debt and Equity Securities [Abstract]
Investments, Debt and Equity Securities [Abstract]
Unrealized gains (losses) on cash flow hedges, net of tax
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax
Scenario [Axis]
Scenario [Axis]
Proceeds from maturities and sales
Proceeds from Sale and Maturity of Debt Securities, Available-for-sale
Investment in biotechnology companies that are determined to be unconsolidated variable interest entities
Investment in biotechnology companies that are determined to be unconsolidated variable interest entities
Investment in biotechnology companies that are determined to be unconsolidated variable interest entities.
Additional paid-in capital
Additional Paid in Capital
Ionis, Sangamo, Denali and Sage
Ionis, Sangamo, Denali and Sage [Member]
Ionis, Sangamo, Denali and Sage
Cash equivalents
Cash Equivalents, at Carrying Value
Impairment of intangible assets
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)
LIABILITIES AND EQUITY
Liabilities and Equity [Abstract]
Hedging Relationship [Domain]
Hedging Relationship [Domain]
Derivative contracts
Foreign Currency Contract, Asset, Fair Value Disclosure
Income Tax Contingency [Table]
Income Tax Contingency [Table]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table]
Earnings per Share
Earnings Per Share [Text Block]
Repurchase of common stock, at cost
Treasury Stock, Value, Acquired, Cost Method
Net gains (losses) recognized during the period on equity securities
Equity Securities, FV-NI, Gain (Loss)
Equity Method Investment, Ownership Percentage
Percentage of stake in entity maximum
Equity Method Investment, Ownership Percentage
Entity Interactive Data Current
Entity Interactive Data Current
Expected future amortization expense, 2023
Finite-Lived Intangible Asset, Expected Amortization, Year Four
Other Consolidated Financial Statement Detail
Additional Financial Information Disclosure [Text Block]
Issuance of common stock under stock award plan
Stock Issued During Period, Value, Stock Options Exercised
Minimum
Minimum
Minimum [Member]
FUMADERM
FUMADERM [Member]
FUMADERM [Member]
Realized gains
Debt Securities, Available-for-sale, Realized Gain
Gains (losses) on net investment hedges, net of tax
Derivatives used in Net Investment Hedge, Net of Tax, Period Increase (Decrease)
Other changes in operating assets and liabilities, net
Increase (Decrease) in Other Operating Assets and Liabilities, Net
Facility Location [Domain]
Facility Location [Domain]
-- None. No documentation exists for this element. --
Biologics Manufacturing
Biologics Manufacturing [Member]
Biologics Manufacturing
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
Total
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Comprehensive income (loss) attributable to noncontrolling interests, net of tax
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Income before income tax expense and equity in loss of investee, net of tax
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest
Selling, general and administrative
Selling, General and Administrative Expense
Indefinite-lived Intangible Assets [Axis]
Indefinite-lived Intangible Assets [Axis]
Other comprehensive income:
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Gross unrealized gains
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Entity Address, State or Province
Entity Address, State or Province
Restructuring reserve, beginning
Restructuring reserve, ending
Restructuring Reserve
Deferred tax asset
Deferred Income Tax Assets, Net
Current liabilities:
Liabilities, Current [Abstract]
Other revenues from anti-CD20 therapeutic programs
Other revenues from anti-CD20 therapeutic programs
Other revenues from anti-CD20 therapeutic programs consists of revenue on sales of RITUXAN outside the U.S., which consist of our share of pre-tax co-promotion profits in Canada and royalty revenue on sales of Ocrevus.
Currency translation adjustments
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Indebtedness
Debt Disclosure [Text Block]
Facility Type [Domain]
Facility Type [Domain]
Facility Type
Share-based Payments
Share-based Payment Arrangement [Text Block]
BENEPALI
BENEPALI [Member]
BENEPALI [Member]
Significant Unobservable Inputs (Level 3)
Fair Value, Inputs, Level 3 [Member]
Inventory
Inventory Disclosure [Text Block]
Amortization of basis differences
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity
Accounting Policies [Abstract]
Accounting Policies [Abstract]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Number of reportable segments
Number of Reportable Segments
Financial Instruments
Cash, Cash Equivalents, and Marketable Securities [Text Block]
Marketable equity securities
Debt Securities, Trading, and Equity Securities, FV-NI, Cost [Abstract]
Total inventory
Inventory, net current and noncurrent
Inventory, net current and noncurrent
Document Transition Report
Document Transition Report
Foreign exchange gains (losses), net
Foreign Currency Transaction Gain (Loss), before Tax
Gross Unrealized Gains
Equity Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Equity Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Common stock, par value $0.0005 per share
Common Stock, Value, Issued
Strategic Investments
Strategic Investments [Member]
Strategic investments.
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Other income (expense), net
Nonoperating Income (Expense)
Total other income (expense), net
Nonoperating Income (Expense)
Components of inventories
Inventory, Net [Abstract]
Total reserves included in consolidated balance sheets
Summary Of Product Revenue Reserves Included In Consolidated Balance Sheets [Table Text Block]
Summary of total product revenue reserves included in consolidated balance sheets.
Inventory
Inventory, Net Current and Noncurrent
Inventory, Net Current and Noncurrent
Basis of presentation
Basis of Accounting, Policy [Policy Text Block]
Net increase (decrease) in cash and cash equivalents
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect
Commitments, contingencies and guarantees
Commitments and Contingencies
Future Contingent Milestone Types [Domain]
Future Contingent Milestone Types [Domain]
[Domain] for Future Contingent Milestone Types [Axis]
Accumulated other comprehensive income (loss)
Accumulated other comprehensive income (loss), net of tax beginning balance
Balance, January 1, 2018
Accumulated other comprehensive income (loss), net of tax ending balance
Accumulated Other Comprehensive Income (Loss), Net of Tax
Entity Emerging Growth Company
Entity Emerging Growth Company
Accrued income taxes
Accrued Income Taxes, Noncurrent
Excess and obsolescence charges related to inventory
Inventory Write-down
Contract Option Exercise Fee
Contract Option Exercise Fee
Contract Option Exercise Fee
Payables To Divestiture Of Interest In Joint Venture
Payables To Divestiture Of Interest In Joint Venture
Payables To Divestiture Of Interest In Joint Venture
Reclassification out of Accumulated Other Comprehensive Income [Axis]
Reclassification out of Accumulated Other Comprehensive Income [Axis]
Derivative Instruments, Unrealized Gain (Loss)
Derivative Instruments, Unrealized Gain (Loss) [Table Text Block]
Derivative Instruments, Unrealized Gain (Loss)
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name [Domain]
Legal Entity [Axis]
Legal Entity [Axis]
Cover [Abstract]
Cover [Abstract]
Stock units
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements
Total cost and expense
Costs and Expenses
Other comprehensive income (loss), before reclassifications, net of tax
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
British pound
United Kingdom, Pounds
Income Tax Contingency [Line Items]
Income Tax Contingency [Line Items]
Equity method investment basis difference amortization period
Equity method investment basis difference amortization period
Equity method investment basis difference amortization period
Work in process
Inventory, Work in Process, Net of Reserves
Payment Due At First Anniversary
Payment Due At First Anniversary [Member]
Payment Due At First Anniversary
Administrative Space
Administrative Space [Member]
Administrative Space
(Gain) loss on strategic investments
Increase (Decrease) in Equity Securities, FV-NI
Financial Instrument [Axis]
Financial Instrument [Axis]
Entity [Domain]
Entity [Domain]
Selling, general and administrative
Selling, General and Administrative Expenses [Member]
Derivative Maturity [Axis]
Derivative Maturity [Axis]
Derivative Maturity [Axis]
Gross Unrealized Losses
Equity Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax
Equity Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax
Schedule of Available-for-sale Securities [Table]
Schedule of Available-for-sale Securities [Table]
Finished goods
Inventory, Finished Goods, Net of Reserves
Number of square feet
Number of Square Feet
Number of Square Feet
Performance stock units settled in stock
Performance Stock Units Settled in Stock [Member]
Performance Stock Units Settled in Stock [Member]
Equity [Abstract]
Equity [Abstract]
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Document Quarterly Report
Document Quarterly Report
Credits and net operating loss utilization
Effective Income Tax Rate Reconciliation, Tax Credit, Percent
Interferon
Interferon [Member]
Interferon
Payment
Payments for Restructuring
Measurement Input Type [Domain]
Measurement Input Type [Domain]
Effect of exchange rate changes on cash and cash equivalents
Effect of Exchange Rate on Cash and Cash Equivalents
Corporate debt securities Non-current
Corporate Debt Securities Non Current [Member]
Corporate Debt Securities Non Current.
Interest income
Investment Income, Interest
Common stock
Common Stock [Member]
Samsung Bioepis
Samsung Biosimilar Agreement [Member]
Samsung bio-similar agreement.
Income from operations
Operating Income (Loss)
Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Gain (loss) recognized in net income, excluded component
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net
Canadian dollar
Canada, Dollars
Research and development costs, percentage
Research and Development Costs, Percentage
Research and Development Costs, Percentage
Short-term derivative
Short-term derivative [Member]
Short-term derivative [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale [Line Items]
Due after one year through five years, estimated fair value
Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, after Year One Through Five
Gross unrealized losses
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax
Collaborative and Other Relationships
Collaborative Arrangement Disclosure [Text Block]
Expected future amortization expense, 2021
Finite-Lived Intangible Asset, Expected Amortization, Year Two
Schedule of Cash and Cash Equivalents [Table]
Schedule of Cash and Cash Equivalents [Table]
Hedging Designation [Axis]
Hedging Designation [Axis]
Issuance of common stock under stock option and stock purchase plans
Stock Issued During Period, Value, Treasury Stock Reissued
Document Fiscal Year Focus
Document Fiscal Year Focus
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Abstract]
Share-based compensation
Share-based Payment Arrangement, Noncash Expense
Restructuring, Business Transformation and Other Cost Saving Initiatives
Restructuring and Related Activities Disclosure [Text Block]
Additional paid-in capital
Additional Paid-in Capital [Member]
Depreciation
Depreciation
Repayments of borrowings and premiums paid on debt exchange
Repayments of Debt
Unrealized Gain on Derivatives
Unrealized Gain on Derivatives
Unrealized Gain on Derivatives
Debt Instrument, Redemption, Amount
Debt Instrument, Redemption, Amount
Debt Instrument, Redemption, Amount
Contingent additional milestone payment
Contingent Milestone Payments Made To Collaborative Partner
Contingent Milestone Payments Made To Collaborative Partner
Treasury stock
Treasury Stock [Member]
Gain on interest rate swap
Gain (Loss) on Derivative Instruments, Net, Pretax
Accrued expense and other current liabilities
Increase (Decrease) in Accrued Liabilities
Purchases of marketable securities
Payments to Acquire Debt Securities, Available-for-sale
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Asset impairment charges
Asset Impairment Charges
Derivative, Notional Amount
Derivative, Notional Amount
Other, net
Other Nonoperating Income (Expense)
Retirement of common stock pursuant to Share Repurchase Programs, at cost, shares
Stock Repurchased and Retired During Period, Shares
Other
Payments for (Proceeds from) Other Investing Activities
Purchases of property, plant and equipment
Payments to Acquire Property, Plant, and Equipment
Accrued expense and other
Total accrued expense and other
Other Liabilities, Current
Interest in subsidiary (less than given percentage)
Interest In Subsidiary
Interest in subsidiary.
Maximum
Maximum
Maximum [Member]
Reconciliation between the U.S. federal statutory tax rate and effective tax rate
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Share-based Payment Arrangement [Abstract]
Share-based Payment Arrangement [Abstract]
Neurimmune
Neurimmune [Member]
Neurimmune.
Total liabilities
Liabilities
Intangible assets
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Raw materials
Inventory, Raw Materials, Net of Reserves
BAN2401 and Elenbecestat
E2609 and BAN2401 [Member]
E2609 and BAN2401 [Member]
JAPAN
JAPAN
Accrued expenses and other
Schedule of Accrued Liabilities [Table Text Block]
Award Type [Axis]
Award Type [Axis]
Expected future amortization expense, 2020
Finite-Lived Intangible Asset, Expected Amortization, Year One
Cash flows from financing activities:
Net Cash Provided by (Used in) Financing Activities [Abstract]
Summary of share based compensation expense associated with different programs [Abstract]
Summary of share based compensation expense associated with different programs [Abstract]
Summary of share-based compensation expense associated with different programs.
Measurement Input Type [Axis]
Measurement Input Type [Axis]
Total Biogen Inc. shareholders’ equity
Stockholders' Equity Attributable to Parent
City Area Code
City Area Code
Designated as hedging instrument
Designated as Hedging Instrument [Member]
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets Disclosure [Abstract]
Entity Address, City or Town
Entity Address, City or Town
Gain (Loss) on Extinguishment of Debt
Gain (Loss) on Extinguishment of Debt
Repayments of Senior Debt
Repayments of Senior Debt
Collaboration expense
Collaboration expenses accrual
Collaboration expenses accrual
Realized losses
Debt Securities, Available-for-sale, Realized Loss
Purchases of treasury stock
Payments for repurchase of common stock
Payments for Repurchase of Common Stock
Other revenues
Other revenues [Table Text Block]
Other revenues [Table Text Block]
Biogen Idec Inc. shareholders' equity
Stockholders' Equity Attributable to Parent [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
Derivative Maturity [Domain]
Derivative Maturity [Domain]
[Domain] for Derivative Maturity [Axis]
Current portion of notes payable
Notes Payable, Current
Future Contingent Milestone Types [Axis]
Future Contingent Milestone Types [Axis]
Future Contingent Milestone Types [Axis]
Employee stock purchase plan
Employee Stock Purchase Plan [Member]
Employee stock purchase plan.
Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Long-term operating lease liabilities
Operating Lease, Liability, Noncurrent
Accrued expenses and other
Accrued Liabilities [Member]
Measurement Frequency [Domain]
Measurement Frequency [Domain]
Loss Contingency, Information about Litigation Matters [Abstract]
Loss Contingency, Information about Litigation Matters [Abstract]
Interest Expense
Interest expense
Interest Expense
Analysis of change In reserves
Analysis Of Amount Of And Change In Product Revenue Reserves [Table Text Block]
Analysis of amount of and change in product revenue reserves.
Income tax effect
Share-based Payment Arrangement, Expense, Tax Benefit
Proceeds from marketable debt securities
Realized Gain (Loss) on Investments [Table Text Block]
Retained earnings
Retained Earnings (Accumulated Deficit)
Equity in (income) loss of investee, net of tax
Income (Loss) from Equity Method Investments, Net of Tax
Income (Loss) from Equity Method Investments, Net of Tax
Derivatives [Line Items]
Derivatives, Fair Value [Line Items]
2.250% Senior Notes due May 1, 2030
2.25% Senior Notes due May 1, 2030 [Member]
2.25% Senior Notes due May 1, 2030 [Member]
Statement of Stockholders' Equity [Abstract]
Statement of Stockholders' Equity [Abstract]
Entity Filer Category
Entity Filer Category
Business Acquisition [Line Items]
Business Acquisition [Line Items]
Term of collaboration agreement
Term of collaboration agreement
Term of collaboration agreement
Summary of the effect of cash flow derivatives designated as hedging instruments on the condensed consolidated statements of income
Derivative Instruments, Gain (Loss) [Table Text Block]
Share Repurchase Program [Axis]
Share Repurchase Program [Axis]
Investment in Samsung Bioepis
Equity Method Investments
Income Statement [Abstract]
Income Statement [Abstract]
UCB Pharma S.A. [Member]
UCB Pharma S.A. [Member]
UCB Pharma S.A. [Member]
Entity Registrant Name
Entity Registrant Name
Fair Value by Asset Class
Asset Class [Domain]
Asset Class [Domain]
Inventory Disclosure [Abstract]
Inventory Disclosure [Abstract]
Prepaid research and development expenses
Prepaid Expense and Other Assets
Fair value of contingent consideration obligations
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Other noncurrent assets
Other Noncurrent Assets [Member]
Notes payable, fair value
Notes Payable, Fair Value Disclosure
Cost and Net
Indefinite-lived Intangible Assets (Excluding Goodwill)
Indefinite-lived Intangible Assets (Excluding Goodwill)
Remaining duration of Net Investment Hedges
Derivative, Term of Contract
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Total equity
Beginning balance
Ending balance
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
Income tax (benefit) expense
Income Tax Expense (Benefit)
Income Tax Expense (Benefit)
Biosimilars
Biosimilars [Member]
Biosimilars
Other
Goodwill, Other Increase (Decrease)
Accounts receivable, net
Accounts Receivable, after Allowance for Credit Loss, Current
Amendment Flag
Amendment Flag
Equity Components [Axis]
Equity Components [Axis]
Accumulated Other Comprehensive Income (Loss) [Table]
Accumulated Other Comprehensive Income (Loss) [Table]
Entity Tax Identification Number
Entity Tax Identification Number
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Abstract]
Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis]
Antidilutive Securities [Axis]
Investment Type [Axis]
Investment Type [Axis]
Document Fiscal Period Focus
Document Fiscal Period Focus
Total current assets
Assets, Current
Net (distribution) contribution to noncontrolling interest
Proceeds from (Payments to) Noncontrolling Interests
Reduction of accounts receivable
Accounts Receivable [Member]
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Inventory
Inventory, Net
Schedule of Stock by Class [Table]
Schedule of Stock by Class [Table]
Unrealized Loss on Derivatives
Unrealized Loss on Derivatives
Unrealized Loss on Derivatives
Schedule of Variable Interest Entities [Table]
Schedule of Variable Interest Entities [Table]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Statement of Financial Position [Abstract]
Statement of Financial Position [Abstract]
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Long Term Debt, Exchanged, Amount
Long Term Debt, Exchanged, Amount
Long Term Debt, Exchanged, Amount
Contingent consideration obligations
Business Combination, Contingent Consideration, Liability, Noncurrent
Product and Service [Axis]
Product and Service [Axis]
Due from anti-CD20 therapeutic programs
Increase (Decrease) in Due from Related Parties
Summary of financial assets with maturities of less than 90 days included within cash and cash equivalents
Schedule of Cash and Cash Equivalents [Table Text Block]
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share
Equity Component [Domain]
Equity Component [Domain]
Government securities Current
Government Securities Current [Member]
Government securities Current.
Revenues from anti-CD20 therapeutic programs
Revenues from anti-CD20 therapeutic programs [Table Text Block]
Revenues from anti-CD20 therapeutic programs
Unrealized gain (loss) on net investment hedges in AOCI
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, before Tax
Stockholders' Equity, Other
Stockholders' Equity, Other
Collaboration agreement term
Collaboration Agreement Term
Collaboration Agreement Term
Currency translation adjustment
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Summary of Activity Related to Aducanumab Collaboration
Summary of Activity Related to Aducanumab Collaboration [Table Text Block]
[Table Text Block] for Summary of Activity Related to Aducanumab Collaboration [Table]
Variable Interest Entity [Line Items]
Variable Interest Entity [Line Items]
Schedule of Equity Method Investments [Table]
Schedule of Equity Method Investments [Table]
Genentech
Roche Group Genentech Member
Roche group Genentech.
5.200% Senior Notes due 2045
Senior Notes Five Point Two Percent Due Twenty Forty Five [Member]
Senior Notes Five Point Two Percent Due Twenty Forty Five [Member]
Potential future milestone payments commitment to third party
Potential Future Milestone Payments Commitment To Third Party Approximately
Potential future milestone payments commitment to third party approximately.
Statement [Line Items]
Statement [Line Items]
SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain]
SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain]
Marketable securities
Debt Securities, Available-for-sale, Noncurrent
Solothurn, Switzerland
Solothurn, Switzerland [Member]
Solothurn, Switzerland [Member]
Summary of Contractual Maturities: Available-for-Sale Securities
Available-for-sale Securities, Debt Maturities [Abstract]
Summary of share-based compensation expense associated with each of our share-based compensating programs
Share-based Payment Arrangement, Cost by Plan [Table Text Block]
Facility Type [Axis]
Facility Type [Axis]
Facility Type
Marketable debt securities
Fair value
Estimated Fair Value
Debt Securities, Available-for-sale
Japan, Yen
Japan, Yen
Summary of fair and carrying value of debt instruments
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]
Counterparty Name [Domain]
Counterparty Name [Domain]
Retirement of common stock pursuant to Share Repurchase Progams, at cost
Treasury Stock, Retired, Cost Method, Amount
Total intangible assets, gross
Intangible Assets, Gross (Excluding Goodwill)
Debt Disclosure [Abstract]
Debt Disclosure [Abstract]
Weighted Average
Weighted Average [Member]
Workforce Reduction
Workforce Reduction [Member]
Workforce Reduction
Accrued Expenses and Other
Accrued Liabilities, Current [Abstract]
Government securities Non-current
Government Securities Non-current [Member]
Government Securities Non Current.
Other revenues [Abstract]
Other revenues [Abstract]
Other revenues [Abstract]
Significant Other Observable Inputs (Level 2)
Fair Value, Inputs, Level 2 [Member]
Deferred tax assets, unrecognized tax benefit
Deferred Tax Assets, Valuation Allowance
Vixotrigine
Vixotrigine [Member]
Vixotrigine
Type of Restructuring [Domain]
Type of Restructuring [Domain]
Amortized Cost
Debt Securities, Available-for-sale, Amortized Cost
Estimated life, (in years)
Finite-Lived Intangible Asset, Useful Life
Customer [Axis]
Customer [Axis]
Restructuring Cost and Reserve [Line Items]
Restructuring Cost and Reserve [Line Items]
Collaboration profit (loss) sharing
Collaboration profit (loss) sharing
Collaboration profit (loss) sharing
Use of estimates
Use of Estimates, Policy [Policy Text Block]
Basic and diluted earnings per share
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Asset Class [Axis]
Asset Class [Axis]
Total other comprehensive income (loss), net of tax
Other comprehensive income (loss), net of tax
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent
Share-based compensation expense included in condensed consolidated statements of income
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
Forecast
Forecast [Member]
Title of 12(b) Security
Title of 12(b) Security
Derivative qualifying as net investment hedge, excluded component
AOCI, Derivative Qualifying as Hedge, Excluded Component, after Tax
Total assets
Assets
Gains (losses) on investments, net
Realized Investment Gains (Losses)
Investment, Name [Domain]
Investment, Name [Domain]
Performance stock units settled in cash
Performance Stock Units Settled in Cash [Member]
Performance Stock Units Settled in Cash [Member]
Payment Due At Second Anniversary
Payment Due At Second Anniversary [Member]
Payment Due At Second Anniversary
Numerator:
Net Income (Loss) Attributable to Parent [Abstract]
Geographical [Domain]
Geographical [Domain]
Document Type
Document Type
Research and development expense
Research and Development Expense
Noncontrolling interest
Noncontrolling Interest [Member]
Product and Service [Domain]
Product and Service [Domain]
Senior notes interest rate
Debt Instrument, Interest Rate, Stated Percentage
Derivative Contract [Domain]
Derivative Contract [Domain]
Other corporate revenues
Other corporate revenues [Member]
Other corporate revenues [Member]
Net income (loss) attributable to noncontrolling interests, net of tax
Net Income (Loss) Attributable to Noncontrolling Interest
Time-vested restricted stock units
Time Vested Restricted Stock Units [Member]
Time vested restricted stock units.
Contingent consideration obligations
Fair value, beginning of period
Fair value, end of period
Business Combination, Contingent Consideration, Liability
Cash flows, revenue
Cash flows, revenue [Member]
Cash flows, revenue [Member]
Amortized Cost
Equity Securities, FV-NI, Cost
Expense reflected within statements of income
Expense reflected within statements of income
Expense reflected within statements of income
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Abstract]
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Abstract]
Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Abstract]
Overnight reverse repurchase agreements
Repurchase Agreements [Member]
Summary of significant accounting policies
Significant Accounting Policies [Text Block]
All Currencies [Domain]
All Currencies [Domain]
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Net cash flow provided by (used in) operating activities
Net Cash Provided by (Used in) Operating Activities
Fair Value, Recurring and Nonrecurring [Table]
Fair Value, Recurring and Nonrecurring [Table]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Cash and Cash Equivalents [Line Items]
Cash and Cash Equivalents [Line Items]
Geographical [Axis]
Geographical [Axis]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Basic earnings per share attributable to Biogen Inc.
Weighted average number of common shares outstanding
Weighted Average Number of Shares Outstanding, Basic
Diluted earnings per share attributable to Biogen Inc.
Earnings Per Share, Diluted
2020 Share Repurchase Program
2020 Share Repurchase Program [Member]
2020 Share Repurchase Program [Member]
Dilutive potential common shares
Weighted Average Number Diluted Shares Outstanding Adjustment
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Product, net
Product [Member]
Net Investment Hedging
Net Investment Hedging [Member]
Hedging Relationship [Axis]
Hedging Relationship [Axis]
Revenue
Sales [Member]
Mortgage and other asset backed securities Non-current
Mortgage And Other Asset Backed Securities Non Current [Member]
Mortgage And Other Asset Backed Securities Non Current.
Swiss franc
Switzerland, Francs
Payments/Returns Relating To Sales in Current Year
Payments Returns Applied Against Product Revenue Reserves Relating To Current Year
Payments/ returns applied against product revenue reserves relating to current year.
Issuance of common stock under stock option and stock purchase plans, shares
Stock Issued During Period, Shares, Treasury Stock Reissued
Sangamo Therapeutics, Inc. Agreement
Sangamo Therapeutics, Inc. Agreement [Member]
Sangamo Therapeutics, Inc. Agreement [Member]
Rest of World
Non-US [Member]
Subsequent Events
Subsequent Events [Text Block]
Schedule of Restructuring and Related Costs [Table]
Schedule of Restructuring and Related Costs [Table]
Intangible assets, net
Intangible assets, net
Intangible Assets, Net (Excluding Goodwill)
Comprehensive income (loss) attributable to Biogen Inc.
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Gain/Loss on fair value of foreign currency forward contracts
Unrealized Gain (Losses) on Foreign Currency Derivatives, Net, before Tax
Amount of net unrealized gain (loss) related to the change in fair value of foreign currency exchange rate derivatives designated as cash flow hedging instruments. Recorded in accumulated other comprehensive income to the extent that the cash flow hedge is determined to be effective.
Percentage of future development costs related to Eisai
Percentage of future development costs related to Eisai
Percentage of future development costs related to Eisai
Net cash flow provided by (used in) financing activities
Net Cash Provided by (Used in) Financing Activities
Treasury stock, at cost
Treasury Stock, Value
Weighted-average shares used in calculating:
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Warehouse, Utilities and Support Space
Warehouse, Utilities and Support Space [Member]
Warehouse, Utilities and Support Space
Deferred tax liability
Deferred Income Tax Liabilities, Net
Other long-term liabilities
Other Noncurrent Liabilities [Member]
(Gain) loss on equity method investments
(Gain) loss on equity method investments
Income (loss) from equity method investments
Income (Loss) from Equity Method Investments
3.250% Senior Notes, Due February 15, 2051
3.250% Senior Notes, Due February 15, 2051 [Member]
3.250% Senior Notes, Due February 15, 2051
Notes payable, carrying value
Notes Payable
Corporate debt securities
Corporate Debt Securities [Member]
Reconciliation between the U.S. federal statutory tax rate and effective tax rate
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Fair Value Measurements
Fair Value Disclosures [Text Block]
Summary of assets and liabilities recorded at fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Cash flows, operating expenses
Cash flows, operating expenses [Member]
Cash flows, operating expenses [Member]
Accounts payable
Accounts Payable, Current
Restructuring charges
Expense
Restructuring Charges
Parent
Total share-based compensation expense, net of tax
Parent [Member]
Depreciation and amortization
Depreciation, Depletion and Amortization
Summary of assets and liabilities recorded at fair value
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Expected future amortization expense, 2022
Finite-Lived Intangible Asset, Expected Amortization, Year Three
Subtotal
Subtotal
Share-based Payment Arrangement, Expense, after Tax
Share-based Compensation Expense included in consolidated statements of income
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Abstract]
Accumulated Other Comprehensive Income
AOCI Attributable to Parent [Member]
Expected future amortization expense, 2019 (remaining three months)
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year
Inventory
Increase (Decrease) in Inventories
Royalties and licensing fees
Accrued Royalties, Current
Due after five years, estimated fair value
Available For Sale Securities Debt Maturities After Five Years Fair Value
This item represents the fair value of debt securities, which are expected to mature after five years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.
Beginning balance, shares
Ending balance, shares
Common Stock, Shares, Outstanding
Financial Instruments [Domain]
Financial Instruments [Domain]
Cost of sales, excluding amortization and impairment of acquired intangible assets
Cost of Goods and Services Sold
Average maturity of marketable securities, months
Average Maturity Of Marketable Securities
Average remaining time to maturity of marketable debt securities, available-for-sale securities.
Restructuring and Related Activities [Abstract]
Document Period End Date
Document Period End Date
Corporate debt securities Current
Corporate Debt Securities Current [Member]
Corporate debt securities Current.
Proceeds from divestiture of Hillerød, Denmark manufacturing operations
Proceeds from Divestiture of Businesses
Equity Securities, Current
Equity Securities, Current [Member]
Equity Securities, Current
Entity Central Index Key
Entity Central Index Key
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unrealized gains (losses) on securities available for sale, net of tax
OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax
Other
Product and Service, Other [Member]
Consolidated Entities [Domain]
Consolidated Entities [Domain]
Overview
Business Overview [Policy Text Block]
Describes an overview of the company and its operations.
Summary of Activity Related to BAN2401 and Elenbecestat Collaboration
Summary of Activity Related to E2609 and BAN2401 Collaboration [Table Text Block]
[Table Text Block] for Summary of Activity Related to E2609 and BAN2401 Collaboration [Table]
State taxes
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent
Returns
Sales Returns and Allowances [Member]
Income Statement Location [Domain]
Income Statement Location [Domain]
Equity:
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Marketable equity securities
Investments, Fair Value Disclosure
Additional milestone payment
Additional Milestone Payment
Additional milestone payment.
Due in one year or less, amortized cost
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One
ADUHELM
ADUHELM [Member]
ADUHELM
Property, plant and equipment, net
Property, Plant and Equipment, Net
Operating Expenses
Operating Expenses
Property, Plant and Equipment
Property, Plant and Equipment Disclosure [Text Block]
Due after five years, amortized cost
Available For Sale Securities Debt Maturities After Five Years Amortized Cost
This item represents debt securities, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are expected to mature after five years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.
TGN
TGN [Member]
TGN
Accrued milestone payments
Accrued Milestone Payments
Accrued Milestone Payments
Expense Incurred By Collaboration
Expense Incurred By Collaboration
Total expense incurred by collaboration.
Regulatory Milestones
Regulatory Milestones [Member]
Regulatory Milestones [Member]
Other long-term liabilities
Other Liabilities, Noncurrent
Estimated future amortization for acquired intangible assets
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Repurchase of common stock, at cost, shares
Repurchase of common stock, at cost, shares
Treasury Stock, Shares, Acquired
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Repayment of borrowings and premiums paid on debt exchange
Repayments of Long-term Debt
Trading Symbol
Trading Symbol
Net income per share:
Earnings Per Share [Abstract]
Earnings Per Share [Abstract]
Collaborative arrangement
Collaborative Arrangement [Member]
Fixed assets placed into service
Property, Plant and Equipment, Gross
Unrealized gains (losses) recognized during the period on equity securities
Net gains recognized on the increase in fair value of equity securities
Equity Securities, FV-NI, Unrealized Gain (Loss)
Total revenue
Product revenues
Total revenues from anti-CD20 therapeutic programs
Other Revenues
Revenues
Amounts reclassified from accumulated other comprehensive income, net of tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax
Component of accrued expenses and other
Other Current Liabilities [Member]
Employee related costs
Severance Costs
Foreign exchange contract
Foreign Exchange Contract [Member]
Proceeds from Divestiture of Interest in Joint Venture
Proceeds from Divestiture of Interest in Joint Venture
Reclassification out of Accumulated Other Comprehensive Income [Table]
Reclassification out of Accumulated Other Comprehensive Income [Table]
Cost and expenses:
Costs and Expenses [Abstract]
Liabilities:
Liabilities, Fair Value Disclosure [Abstract]
Compensation related to share-based payments
Share-based compensation expense
Share-based Payment Arrangement, Expense
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Line Items]
Strategic investment portfolio
Strategic Investment Portfolio
Strategic investment portfolio.
FLIXABI
FLIXABI [Member]
FLIXABI [Member]
Entity Current Reporting Status
Entity Current Reporting Status
Effective tax rate
Effective Income Tax Rate Reconciliation, Percent
Loss Contingency, Estimate of Possible Loss
Loss Contingency, Estimate of Possible Loss
Due from anti-CD20 therapeutic programs
Due from anti-CD20 therapeutic programs
Receivable from anti-CD20 therapeutic programs for our share of the pre-tax co-promotion profits generated from our co-promotion arrangement for sales of RITUXAN.
Reclassification out of Accumulated Other Comprehensive Income [Domain]
Reclassification out of Accumulated Other Comprehensive Income [Domain]
Net income
Net income
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Investment Type Categorization [Domain]
Investments [Domain]
Counterparty Name [Axis]
Counterparty Name [Axis]
Proceeds from sales and maturities of marketable securities
Proceeds from Sale and Maturity of Marketable Securities
Cash and cash equivalents
Cash and cash equivalents, beginning of the period
Cash and cash equivalents, end of the period
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Facility Location [Axis]
Facility Location [Axis]
-- None. No documentation exists for this element. --
U.S.
UNITED STATES
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Discount rate
Measurement Input, Discount Rate [Member]
Investments in Variable Interest Entities
Variable Interest Entity Disclosure [Text Block]
Taxes payable
Taxes Payable, Current
Current assets:
Assets, Current [Abstract]
Statement of Comprehensive Income [Abstract]
Statement of Comprehensive Income [Abstract]
Other
Proceeds from (Payments for) Other Financing Activities
Cost
Finite-Lived Intangible Assets, Gross
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cash equivalents
Cash and Cash Equivalents, Fair Value Disclosure
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
Issuance of common stock under award plan, shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period
Diluted earnings per share attributable to Biogen Inc.
Shares used in calculating diluted earnings per share
Weighted Average Number of Shares Outstanding, Diluted
Other comprehensive income (loss), net of tax
Other Comprehensive Income (Loss), Net of Tax
Estimated additional payments upon achievement of development and commercial milestones
Estimated Additional Payments Upon Achievement Of Development And Commercial Milestones
Estimated additional payments upon achievement of development and commercial milestones.
Amortization
Amortization
Fair Value, Measurements, Recurring
Fair Value, Recurring [Member]
Sage Therapeutics Inc.
Sage Therapeutics Inc. [Member]
Sage Therapeutics Inc.
Income Taxes
Income Tax Disclosure [Text Block]
Equity
Stockholders' Equity Note Disclosure [Text Block]
Unrealized gains (losses) on cash flow hedges
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Amortization and impairment of acquired intangible assets
Amortization and Impairment of Acquired Intangible Assets
Amortization and Impairment of Acquired Intangible Assets
Purchased intangible assets
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depreciation and Amortization, Percent
Expected future amortization expense, 2024
Finite-Lived Intangible Asset, Expected Amortization, Year Five
MS Product Revenues
MS Product Revenues [Member]
MS Product Revenues [Member]
Statement of Cash Flows [Abstract]
Statement of Cash Flows [Abstract]
Payments to acquire additional investment in equity method investment
Payments to Acquire Equity Method Investments
Class of Stock [Line Items]
Class of Stock [Line Items]
Not designated as hedging instrument
Not Designated as Hedging Instrument [Member]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Research and development asset [Axis]
Research and development asset [Axis]
Research and development asset [Axis]
Royalty
Royalty [Member]
Entity Address, Address Line One
Entity Address, Address Line One
Net cash flow provided by (used in) investing activities
Net Cash Provided by (Used in) Investing Activities
Disaggregation of Revenue [Abstract]
Disaggregation of Revenue [Abstract]
Changes in operating assets and liabilities, net:
Increase (Decrease) in Operating Capital [Abstract]
Accumulated depreciation
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Cash flow from operating activities:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Consolidation
Consolidation, Policy [Policy Text Block]
Entity Shell Company
Entity Shell Company
Total current liabilities
Liabilities, Current
Payments related to issuance of stock for share-based compensation arrangements, net
Payment, Tax Withholding, Share-based Payment Arrangement
Accelerated depreciation expense
Restructuring and Related Cost, Accelerated Depreciation
Gain (loss) on foreign currency derivative instruments not designated as hedging instruments
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments
Euro
Euro Member Countries, Euro
FAMPYRA
FAMPYRA [Member]
FAMPYRA [Member]
Foreign Exchange Forward
Foreign Exchange Forward [Member]
Money market funds
Money Market Funds [Member]
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Member]
Current Fiscal Year End Date
Current Fiscal Year End Date
Eisai
Eisai [Member]
Eisai [Member]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Other current assets
Other Assets, Current
Statement [Table]
Statement [Table]
Collaborative Arrangement and Arrangement Other than Collaborative [Table]
Collaborative Arrangement and Arrangement Other than Collaborative [Table]
Distributor One
Distributor One [Member]
Distributor one.
Mortgage and other asset backed securities
Asset-backed Securities [Member]
New accounting pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Effect of dilutive securities:
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Derivative liability, fair value
Derivative Liability, Fair Value, Gross Liability
Range of durations of foreign currency forward contracts
Derivative, Remaining Maturity
Basic and diluted earnings per share
Basic And Diluted Earnings Per Share [Abstract]
Basic and diluted earnings per share.
Summary of Activity Related to Denali Therapeutics Collaboration
Summary of Activity Related to Denali Therapeutics Collaboration [Table Text Block]
Summary of Activity Related to Denali Therapeutics Collaboration
Preferred stock
Preferred Stock [Member]
Net
Finite-Lived Intangible Assets, Net
Goodwill
Goodwill, beginning of period
Goodwill, end of period
Goodwill
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax
Noncontrolling interests
Stockholders' Equity Attributable to Noncontrolling Interest
Taxes on foreign earnings
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent
Beginning Balance
Ending Balance
Total Reserves
Revenue-related reserves for discounts and allowances
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount
Construction in progress
Construction in Progress, Gross
Summary of roll forward of the changes in goodwill
Schedule of Goodwill [Table Text Block]
Scenario [Domain]
Scenario [Domain]
Adjustments to reconcile net income to net cash flow from operating activities:
Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]
Cost of Goods Sold, Capacity Charges
Cost of Goods Sold, Capacity Charges
Cost of Goods Sold, Capacity Charges
Equity Securities, Non-Current
Equity Securities, Non-Current [Member]
Equity Securities, Non-Current
Developed technology
Developed Technology Rights [Member]
Summary of fair value and presentation of derivatives
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Due in one year or less, estimated fair value
Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One
Loss recorded on Samsung Bioepis joint venture
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions
Unfunded status of postretirement benefit plans
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Gains (losses) on net investment hedge, excluded component
Derivatives used in net investment hedge, net of tax, excluded component increase (decrease)
Derivatives used in net investment hedge, net of tax, excluded component increase (decrease)
Inventory [Line Items]
Inventory [Line Items]
Schedule of Finite-Lived Intangible Assets [Table]
Schedule of Finite-Lived Intangible Assets [Table]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred income taxes
Deferred Income Tax Expense (Benefit)
Revenue from anti-CD20 therapeutic programs
Revenues from anti-cd20 therapeutic programs [Member]
Revenues from anti-cd20 therapeutic programs