Expense incurred by the collaboration
Expense incurred by the collaboration
Expense incurred by the collaboration
Document Type
Document Type
Issuance of common stock under stock option and stock purchase plans, shares
Stock Issued During Period, Shares, Treasury Stock Reissued
Other, net
Other Nonoperating Income (Expense)
Intangible assets
Intangible Assets Excluding Goodwill [Table Text Block]
Intangible assets excluding goodwill.
Technological and Regulatory Success, Probability
Technological and Regulatory Success, Probability
Technological and Regulatory Success, Probability
Treasury stock
Treasury Stock [Member]
Summary of Contractual Maturities: Available-for-Sale Securities
Available-for-sale Securities, Debt Maturities [Abstract]
Summary of assets and liabilities recorded at fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain]
SEC Schedule, 12-09, Valuation Allowances and Reserves [Domain]
ZINBRYTA
ZINBRYTA [Member]
ZINBRYTA [Member]
Schedule of Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
In-process research and development
In Process Research and Development [Member]
Significant Unobservable Inputs (Level 3)
Fair Value, Inputs, Level 3 [Member]
Proceeds from sales and maturities of marketable securities
Proceeds from Sale and Maturity of Marketable Securities
Other current assets
Other Current Assets [Member]
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.
Deferred tax liabilities, decrease in value
Deferred Tax Liabilities, Value, Reduction in Value
Deferred Tax Liabilities, Value, Reduction in Value
Unrealized Gross Gains on Foreign Currency Derivatives, Net, before Tax
Unrealized Gross Gains on Foreign Currency Derivatives, Net, before Tax
Unrealized Gross Gains on Foreign Currency Derivatives, Net, before Tax
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
Statistical Measurement [Domain]
Statistical Measurement [Domain]
LIABILITIES AND EQUITY
Liabilities and Equity [Abstract]
Payments subsidiary and affiliates stock
Payments to Acquire Interest in Subsidiaries and Affiliates
Deferred tax liability
Deferred Income Tax Liabilities, Net
Derivative Instruments
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Preferred stock
Preferred Stock [Member]
Denali Therapeutics
Denali Therapeutics Inc [Member]
Denali Therapeutics Inc
Security Exchange Name
Security Exchange Name
Intangible assets, net
Intangible assets, net
Intangible Assets, Net (Excluding Goodwill)
Distribution to noncontrolling interest
Noncontrolling Interest, Increase (Decrease) Other
Noncontrolling Interest, Increase (Decrease) Other
Trademarks and Trade Names
Trademarks and Trade Names [Member]
SPINRAZA
SPINRAZA [Member]
SPINRAZA [Member]
Proceeds from borrowings
Proceeds from Issuance of Long-term Debt
Income from operations
Operating Income (Loss)
Retirement of common stock pursuant to Share Repurchase Progams, at cost
Treasury Stock, Retired, Cost Method, Amount
TYSABRI
TYSABRI product [Member]
TYSABRI product [Member]
Total current liabilities
Liabilities, Current
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Member]
Performance units
Performance Shares [Member]
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.
Investments by Consolidated and Nonconsolidated Entities [Axis]
Investments by Consolidated and Nonconsolidated Entities [Axis]
Realized losses
Debt Securities, Available-for-sale, Realized Loss
Schedule of Business Acquisitions, by Acquisition [Table]
Schedule of Business Acquisitions, by Acquisition [Table]
Commitments and contingencies
Commitments and Contingencies
Marketable securities
Debt Securities, Available-for-sale, Noncurrent
Purchases of treasury stock
Payments for repurchase of common stock
Payments for Repurchase of Common Stock
ASSETS
Assets [Abstract]
Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Investment, Name [Axis]
Investment, Name [Axis]
Accounting Policies [Abstract]
Accounting Policies [Abstract]
Proceeds from sales of strategic investments
Proceeds from Sale and Maturity of Other Investments
Taxes payable
Taxes Payable, Current
Research and development asset [Domain]
Research and development asset [Domain]
[Domain] for Research and development asset [Axis]
Entity Address, State or Province
Entity Address, State or Province
Marketable equity securities
Debt Securities, Trading, and Equity Securities, FV-NI, Cost [Abstract]
Accounts payable
Accounts Payable, Current
Schedule of Cash and Cash Equivalents [Table]
Schedule of Cash and Cash Equivalents [Table]
InnoCare Pharma Limited (InnoCare) Agreement
InnoCare Pharma Limited (InnoCare) Agreement [Member]
InnoCare Pharma Limited (InnoCare) Agreement
Retained earnings
Retained Earnings (Accumulated Deficit)
BIIB111 and BIIB112
BIIB111 and BIIB112 [Member]
BIIB111 and BIIB112
Operating lease assets
Operating Lease, Right-of-Use Asset
Gain (Loss) on Extinguishment of Debt
Gain (Loss) on Extinguishment of Debt
Repurchase of common stock, at cost, shares
Repurchase of common stock, at cost, shares
Treasury Stock, Shares, Acquired
Proceeds from marketable debt securities
Realized Gain (Loss) on Investments [Table Text Block]
Swiss franc
Switzerland, Francs
Equity:
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Summary of assets and liabilities recorded at fair value
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Contractual adjustments
Contractual Adjustments [Member]
Contractual adjustments.
Litigation
Legal Matters and Contingencies [Text Block]
Customer [Axis]
Customer [Axis]
Completed technology
Out Licensed Patents [Member]
Out-licensed patents.
Preferred stock, par value $0.001 per share
Preferred Stock, Value, Issued
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
Hedging Designation [Domain]
Hedging Designation [Domain]
Government securities
US Treasury and Government [Member]
Operating Expenses
Operating Expenses
Payments to acquire additional investment in equity method investment
Payments to Acquire Equity Method Investments
Global licensing collaboration agreement, shares purchased per share (in usd per share)
Global Licensing Collaboration Agreement, Shares Purchased Per Share
Global Licensing Collaboration Agreement, Shares Purchased Per Share
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Payments of financing costs
Payments of Financing Costs
Other long-term liabilities
Other Liabilities, Noncurrent
Deferred tax asset
Deferred Income Tax Assets, Net
Other comprehensive income:
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Other
Payments for (Proceeds from) Other Investing Activities
Market stock units
Market Stock Units [Member]
Market stock units.
Gain (loss) recognized in net income, excluded component
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net
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]
Work in process
Inventory, Work in Process, Net of Reserves
Gain (loss) on foreign currency derivative instruments not designated as hedging instruments
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments
Mortgage and other asset backed securities Current
Mortgage And Other Asset Backed Securities Current [Member]
Mortgage and other asset backed securities Current.
Construction in progress
Construction in Progress, Gross
Inventory
Inventory, Net
Measurement Frequency [Domain]
Measurement Frequency [Domain]
2.90% Senior Notes Due Sept 15, 2020
2.90% Senior Notes Due Sept 15, 2020 [Member]
2.90% Senior Notes Due Sept 15, 2020 [Member]
Neurimmune tax impacts
Effective Tax Rate Reconciliation, NuerImmune Tax Impacts
Effective Tax Rate Reconciliation, NuerImmune Tax Impacts
Loss Contingency, Information about Litigation Matters [Abstract]
Loss Contingency, Information about Litigation Matters [Abstract]
Business Acquisition [Axis]
Business Acquisition [Axis]
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.
Geographical [Domain]
Geographical [Domain]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Statement [Line Items]
Statement [Line Items]
IMRALDI
IMRALDI [Member]
IMRALDI [Member]
Forecast
Forecast [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Table]
Collaborative Arrangement and Arrangement Other than Collaborative [Table]
Percentage of revenues from major distributors
Entity Wide Percentage Of Revenue From Major Distributors
Entity wide percentage of revenue from major distributors.
Contingent consideration obligations
Business Combination, Contingent Consideration, Liability, Noncurrent
Measurement Input Type [Domain]
Measurement Input Type [Domain]
Statement [Table]
Statement [Table]
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Debt instruments, fair value
Debt Instrument, Fair Value Disclosure
Global Licensing Collaboration Agreement, Research, Development, Regulatory and Commercial Milestone Payments
Global Licensing Collaboration Agreement, Research, Development, Regulatory and Commercial Milestone Payments
Global Licensing Collaboration Agreement, Research, Development, Regulatory and Commercial Milestone Payments
Investments in Variable Interest Entities [Abstract]
Investments in Variable Interest Entities [Abstract]
Investments In Variable Interest Entities.
Unrealized gain (loss) on net investment hedges in AOCI
Unrealized Gain (Loss) on Foreign Currency Derivatives, Net, before Tax
Weighted Average
Weighted Average [Member]
Other research and discovery
Other research and discovery [Member]
Other research and discovery [Member]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax
Business Combinations [Abstract]
Business Combinations [Abstract]
Entity Small Business
Entity Small Business
Consolidation
Consolidation, Policy [Policy Text Block]
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.
GILTI
Effective Tax Rate Reconciliation, GILTI tax
Effective Tax Rate Reconciliation, GILTI tax
Indebtedness
Debt Disclosure [Text Block]
Fair Value Hierarchy and NAV [Domain]
Fair Value Hierarchy and NAV [Domain]
Collaborative arrangement
Collaborative Arrangement [Member]
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.
Selling, general and administrative
Selling, General and Administrative Expenses [Member]
Fumarate
Fumarate [Member]
Fumarate [Member]
Share Repurchase Program [Domain]
Share Repurchase Program [Domain]
Summary of roll forward of the changes in goodwill
Goodwill [Roll Forward]
Proceeds from maturities and sales
Proceeds from Sale and Maturity of Debt Securities, Available-for-sale
Amendment Flag
Amendment Flag
Basic and diluted earnings per share
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Weighted-average shares used in calculating:
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Finite-Lived Intangible Assets, Major Class Name [Domain]
Business Acquisition, Contingent Consideration [Line Items]
Business Acquisition, Contingent Consideration [Line Items]
Effect of dilutive securities:
Dilutive Securities, Effect on Basic Earnings Per Share [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]
Other
Other Accrued Liabilities, Current
Repayment of borrowings and premiums paid on debt exchange
Repayments of borrowings and premiums paid on debt exchange
Repayments of Debt
Discounts
Reserve for Cash Discounts [Member]
Reserve for Cash Discounts [Member]
Number of wholesalers
Number of Wholesalers
Number of Wholesalers
Net cash flow provided by operating activities
Net Cash Provided by (Used in) Operating Activities
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]
Entity Central Index Key
Entity Central Index Key
Measurement Frequency [Axis]
Measurement Frequency [Axis]
Unrealized gains (losses) on cash flow hedges
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Marketable securities
Debt Securities, Available-for-sale, Current
Accrued Expenses and Other
Accrued Liabilities, Current [Abstract]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Financial Instruments [Domain]
Financial Instruments [Domain]
Summary of fair and carrying value of debt instruments
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments [Table Text Block]
2018 Share Repurchase Program
2018 Share Repurchase Program [Member]
2018 Share Repurchase Program [Member]
Finite-Lived Intangible Assets by Major Class [Axis]
Finite-Lived Intangible Assets by Major Class [Axis]
Other long-term liabilities
Other Noncurrent Liabilities [Member]
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.
Cash equivalents
Cash Equivalents, at Carrying Value
Senior Notes
Senior Notes [Member]
Geographical [Axis]
Geographical [Axis]
Subsequent Events
Subsequent Events [Text Block]
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.
Ionis, Sangamo, Denali and Sage
Ionis, Sangamo, Denali and Sage [Member]
Ionis, Sangamo, Denali and Sage
Amortized Cost
Debt Securities, Available-for-sale, Amortized Cost
Gross unrealized gains
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax
Accrued income taxes
Accrued Income Taxes, Noncurrent
Statement of Cash Flows [Abstract]
Statement of Cash Flows [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]
Dilutive potential common shares
Weighted Average Number Diluted Shares Outstanding Adjustment
Beginning Balance
Ending Balance
Total Reserves
Revenue-related reserves for discounts and allowances
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount
Effect of exchange rate changes on cash and cash equivalents
Effect of Exchange Rate on Cash and Cash Equivalents
Income Statement Location [Axis]
Income Statement Location [Axis]
Gains (losses) on net investment hedges
Derivatives used in Net Investment Hedge, Net of Tax, Period Increase (Decrease)
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Income Statement Location [Domain]
Income Statement Location [Domain]
Due from anti-CD20 therapeutic programs
Increase (Decrease) in Due from Related Parties
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]
Cash flows from financing activities:
Net Cash Provided by (Used in) Financing Activities [Abstract]
Selling, general and administrative
Selling, General and Administrative Expense
Derivative, Notional Amount
Derivative, Notional Amount
FUMADERM
FUMADERM [Member]
FUMADERM [Member]
Foreign exchange contract
Foreign Exchange Contract [Member]
Deferred tax asset, increase (decrease) in value
Deferred Tax Asset, Increase (Decrease) In Value
Deferred Tax Asset, Increase (Decrease) In Value
Facility Location [Domain]
Facility Location [Domain]
-- None. No documentation exists for this element. --
Biologics Manufacturing
Biologics Manufacturing [Member]
Biologics Manufacturing
Investments and other assets
Other Assets, Noncurrent
Credits and net operating loss utilization
Effective Income Tax Rate Reconciliation, Tax Credit, Percent
Cash equivalents
Cash and Cash Equivalents, Fair Value Disclosure
Number of product candidates
Number of Product Candidates
Number of Product Candidates
Total assets
Assets
Scenario [Axis]
Scenario [Axis]
Impairment of intangible assets
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)
Title of 12(b) Security
Title of 12(b) Security
Accrued expenses and other
Schedule of Accrued Liabilities [Table Text Block]
Net gains (losses) recognized during the period on equity securities
Equity Securities, FV-NI, Gain (Loss)
Net
Finite-Lived Intangible Assets, Net
Purchased intangible assets
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depreciation and Amortization, Percent
Percentage par value of senior notes
Percentage Par Value Of Senior Notes
Percentage Par Value Of Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share, by Antidilutive Securities [Axis]
Antidilutive Securities [Axis]
Amortized Cost
Equity Securities, FV-NI, Cost
Investments, Debt and Equity Securities [Abstract]
Investments, Debt and Equity Securities [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.
Reclassification out of Accumulated Other Comprehensive Income [Axis]
Reclassification out of Accumulated Other Comprehensive Income [Axis]
Japan, Yen
Japan, Yen
Interest Expense
Interest expense
Interest Expense
Facility Type [Domain]
Facility Type [Domain]
Facility Type
Stockholders' Equity, Other
Stockholders' Equity, Other
Depreciation and amortization
Depreciation, Depletion and Amortization
BENEPALI
BENEPALI [Member]
BENEPALI [Member]
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)
BIIB118
BIIB118 [Member]
BIIB118 [Member]
Product and Service [Axis]
Product and Service [Axis]
Total liabilities
Liabilities
Income Tax Contingency [Line Items]
Income Tax Contingency [Line Items]
Canadian dollar
Canada, Dollars
Investment Type [Axis]
Investment Type [Axis]
Revenue
Sales [Member]
Other noncurrent assets
Other Noncurrent Assets [Member]
Total inventory
Inventory, net current and noncurrent
Inventory, net current and noncurrent
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Equity Securities, FV-NI, Gain (Loss), Alternative [Abstract]
Rest of World
Non-US [Member]
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
Strategic Investments
Strategic Investments [Member]
Strategic investments.
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.
Amortization of basis differences
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity
Quoted Prices in Active Markets (Level 1)
Fair Value, Inputs, Level 1 [Member]
Future Contingent Milestone Types [Domain]
Future Contingent Milestone Types [Domain]
[Domain] for Future Contingent Milestone Types [Axis]
Inventory
Increase (Decrease) in Inventories
Fair Value, Recurring and Nonrecurring [Table]
Fair Value, Recurring and Nonrecurring [Table]
Contract Option Exercise Fee
Contract Option Exercise Fee
Contract Option Exercise Fee
2.900% Senior Notes due 2020
Senior Notes Two Point Nine Percent Due Twenty Twenty [Member]
Senior Notes Two Point Nine Percent Due Twenty Twenty [Member]
Raw materials
Inventory, Raw Materials, Net of Reserves
Other changes in operating assets and liabilities, net
Increase (Decrease) in Other Operating Assets and Liabilities, Net
Realized gains
Debt Securities, Available-for-sale, Realized Gain
Debt Instrument [Axis]
Debt Instrument [Axis]
Additional paid-in capital
Additional Paid-in Capital [Member]
TECFIDERA
TECFIDERA [Member]
TECFIDERA [Member]
Other income (expense), net
Schedule of Other Nonoperating Income (Expense) [Table Text Block]
Antidilutive Securities, Name [Domain]
Antidilutive Securities, Name [Domain]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
JAPAN
JAPAN
Class of Stock [Line Items]
Class of Stock [Line Items]
Accrued expense and other current liabilities
Increase (Decrease) in Accrued Liabilities
Asset Class [Axis]
Asset Class [Axis]
Repurchase of common stock, at cost
Treasury Stock, Value, Acquired, Cost Method
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]
Derivative contracts
Foreign Currency Contract, Asset, Fair Value Disclosure
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Abstract]
Cash and Cash Equivalents [Line Items]
Cash and Cash Equivalents [Line Items]
Investment in Samsung Bioepis
Equity Method Investments
Overnight reverse repurchase agreements
Repurchase Agreements [Member]
Beginning balance, shares
Ending balance, shares
Common Stock, Shares, Outstanding
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Abstract]
Equity method investment basis difference amortization period
Equity method investment basis difference amortization period
Equity method investment basis difference amortization period
Investments in Variable Interest Entities
Variable Interest Entity Disclosure [Text Block]
Administrative Space
Administrative Space [Member]
Administrative Space
Research and development expense
Research and Development Expense
Cash proceeds from settlement of swap
Payments for (Proceeds from) Derivative Instrument, Financing Activities
Remaining duration of Net Investment Hedges
Derivative, Term of Contract
Other
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent
Derivative Maturity [Axis]
Derivative Maturity [Axis]
Derivative Maturity [Axis]
Royalty
Royalty [Member]
Stock units
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements
Fixed assets placed into service
Property, Plant and Equipment, Gross
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
Global licensing collaboration agreement, amount, shares purchased (in shares)
Global Licensing Collaboration Agreement, Amount, Shares Purchased
Global Licensing Collaboration Agreement, Amount, Shares Purchased
Operating expense
Operating Expense [Member]
Number of square feet
Number of Square Feet
Number of Square Feet
Net losses recognized on the decrease in fair value of equity securities
Equity Securities, FV-NI, Unrealized Loss
SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis]
SEC Schedule, 12-09, Valuation Allowances and Reserves Type [Axis]
Performance stock units settled in stock
Performance Stock Units Settled in Stock [Member]
Performance Stock Units Settled in Stock [Member]
Interferon
Interferon [Member]
Interferon
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Derivative contracts
Foreign Currency Contracts, Liability, Fair Value Disclosure
Income Statement [Abstract]
Income Statement [Abstract]
Corporate debt securities Non-current
Corporate Debt Securities Non Current [Member]
Corporate Debt Securities Non Current.
Accumulated Other Comprehensive Income
AOCI Attributable to Parent [Member]
Summary of contractual maturities: available-for-sale securities
Investments Classified by Contractual Maturity Date [Table Text Block]
Repayments of Senior Debt
Repayments of Senior Debt
Samsung Bioepis
Samsung Biosimilar Agreement [Member]
Samsung bio-similar agreement.
Long-term operating lease liabilities
Operating Lease, Liability, Noncurrent
Expected future amortization expense, 2023
Finite-Lived Intangible Asset, Expected Amortization, Year Four
Unrealized gains (losses) on pension benefit obligation, net of tax
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax
Royalties and licensing fees
Accrued Royalties, Current
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]
Use of estimates
Use of Estimates, Policy [Policy Text Block]
Current assets:
Assets, Current [Abstract]
Interest income
Investment Income, Interest
Marketable equity securities
Investments, Fair Value Disclosure
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
Amount remaining under 2019 Share Repurchase Program
Stock Repurchase Program, Remaining Authorized Repurchase Amount
Consolidated Entities [Axis]
Consolidated Entities [Axis]
TECFIDERA impairment
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Percent
Comprehensive income attributable to Biogen Inc.
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share
Reconciliation between the U.S. federal statutory tax rate and effective tax rate
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Gain (loss) on investments, net
Realized Investment Gains (Losses)
Scenario [Domain]
Scenario [Domain]
Legal Entity [Axis]
Legal Entity [Axis]
Purchases of property, plant and equipment
Payments to Acquire Property, Plant, and Equipment
City Area Code
City Area Code
Document Period End Date
Document Period End Date
Contingent consideration obligations
Fair value, beginning of period
Fair value, end of period
Business Combination, Contingent Consideration, Liability
Intangible Assets and Goodwill
Goodwill and Intangible Assets Disclosure [Text Block]
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Abstract]
Interest in subsidiary (less than given percentage)
Interest In Subsidiary
Interest in subsidiary.
Net Investment Hedging
Net Investment Hedging [Member]
Acquisitions [Abstract]
Acquisitions [Abstract]
Acquisitions [Abstract]
Neurimmune
Neurimmune [Member]
Neurimmune.
(Gain) loss on equity method investment
Income (loss) from equity method investments
(Gain) loss on equity method investment
Income (Loss) from Equity Method Investments
Stock Repurchase Program, Authorized Amount
Stock Repurchase Program, Authorized Amount
Gain on interest rate swap
Derivative, gain on derivative
Gain (Loss) on Derivative Instruments, Net, Pretax
Net income
Net income
Net income
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
BAN2401 and Elenbecestat
E2609 and BAN2401 [Member]
E2609 and BAN2401 [Member]
Revenues by product
Disaggregation of Revenue [Table Text Block]
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
Amounts reclassified from accumulated other comprehensive income, net of tax
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax
Hedging Designation [Axis]
Hedging Designation [Axis]
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.
Reclassification out of Accumulated Other Comprehensive Income [Domain]
Reclassification out of Accumulated Other Comprehensive Income [Domain]
Global licensing collaboration agreement, purchase price per share (in usd per share)
Global Licensing Collaboration Agreement, Purchase Price Per Share
Global Licensing Collaboration Agreement, Purchase Price Per Share
Accumulated impairment losses related to goodwill
Goodwill, Impaired, Accumulated Impairment Loss
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Net increase (decrease) in cash and cash equivalents
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect
Components of inventory
Schedule of Inventory, Current [Table Text Block]
Capitalized share-based compensation costs
Share-based Payment Arrangement, Amount Capitalized
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]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Share-based compensation
Share-based Payment Arrangement, Noncash Expense
Global Licensing Collaboration Agreement, Payment, Achievement of Specific Sales Based Milestones
Global Licensing Collaboration Agreement, Payment, Achievement of Specific Sales Based Milestones
Global Licensing Collaboration Agreement, Payment, Achievement of Specific Sales Based Milestones
Fair Value
Equity Securities, FV-NI
Entity [Domain]
Entity [Domain]
Other
Proceeds from (Payments for) Other Financing Activities
Payments related to issuance of stock for share-based compensation arrangements, net
Payment, Tax Withholding, Share-based Payment Arrangement
Designated as hedging instrument
Designated as Hedging Instrument [Member]
Intangible assets
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Cover [Abstract]
Cover [Abstract]
Measurement Input Type [Axis]
Measurement Input Type [Axis]
Marketable debt and equity securities
Debt Securities, Available-for-sale [Table Text Block]
Collaboration expense
Collaboration expenses accrual
Collaboration expenses accrual
Retirement of common stock pursuant to Share Repurchase Programs, at cost, shares
Stock Repurchased and Retired During Period, Shares
Other comprehensive income (loss), before reclassifications, net of tax
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax
Other revenues
Other revenues [Table Text Block]
Other revenues [Table Text Block]
Inventory
Inventories [Member]
Derivative Maturity [Domain]
Derivative Maturity [Domain]
[Domain] for Derivative Maturity [Axis]
Capital contribution by noncontrolling interest
Noncontrolling Interest, Capital Contribution
Noncontrolling Interest, Capital Contribution
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.
Notes payable
Long-term Debt
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Abstract]
Unrealized Gross Losses on Foreign Currency Derivatives, Net, before Tax
Unrealized Gross Losses on Foreign Currency Derivatives, Net, before Tax
Unrealized Gross Losses on Foreign Currency Derivatives, Net, before Tax
Short-term debt securities
Debt Securities [Member]
Deferred tax assets, net
Deferred tax assets, net
Deferred Tax Assets, Net
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.
Cost of sales, excluding amortization and impairment of acquired intangible assets
Cost of Goods and Services Sold
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table]
Marketable debt securities
Fair value
Estimated Fair Value
Debt Securities, Available-for-sale
Total cost and expense
Costs and Expenses
Equity Components [Axis]
Equity Components [Axis]
Unrealized gains (losses) on cash flow hedges, net of tax
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax
Finished goods
Inventory, Finished Goods, Net of Reserves
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
Share-based Payment Arrangement [Abstract]
Share-based Payment Arrangement [Abstract]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Deferred tax assets, gross
Deferred Tax Assets, Gross
Minimum
Minimum
Minimum [Member]
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
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]
Consolidated Entities [Domain]
Consolidated Entities [Domain]
Europe
Europe [Member]
Term of collaboration agreement
Term of collaboration agreement
Term of collaboration agreement
Other Income (Expense), Net
Interest Income (Expense), Net [Abstract]
UCB Pharma S.A. [Member]
UCB Pharma S.A. [Member]
UCB Pharma S.A. [Member]
Net income (loss) attributable to noncontrolling interests, net of tax
Net Income (Loss) Attributable to Noncontrolling Interest
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]
Mortgage and other asset backed securities
Asset-backed Securities [Member]
Entity Interactive Data Current
Entity Interactive Data Current
Summary of fair value and presentation of derivatives
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
U.S.
UNITED STATES
Fair Value Measurements
Fair Value Disclosures [Text Block]
Cash flow from operating activities:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Equity
Stockholders' Equity Note Disclosure [Text Block]
Reduction of accounts receivable
Accounts Receivable [Member]
Derivatives [Line Items]
Derivatives, Fair Value [Line Items]
Interest rate swap
Interest Rate Swap [Member]
Expected future amortization expense, 2019 (remaining three months)
Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year
Customer [Domain]
Customer [Domain]
British pound
United Kingdom, Pounds
Biosimilars
Biosimilars [Member]
Biosimilars
Entity Registrant Name
Entity Registrant Name
Business Acquisition [Line Items]
Business Acquisition [Line Items]
Statement of Stockholders' Equity [Abstract]
Statement of Stockholders' Equity [Abstract]
Assets:
Assets, Fair Value Disclosure [Abstract]
Acquired in-process research and development
Payments to Acquire in Process Research and Development
Asset impairment charges
Asset Impairment Charges
Issuance of common stock under stock option and stock purchase plans
Stock Issued During Period, Value, Treasury Stock Reissued
Proceeds from divestiture of Hillerød, Denmark manufacturing operations
Proceeds from Sale of Property, Plant, and Equipment
Total intangible assets, gross
Intangible Assets, Gross (Excluding Goodwill)
Number of reportable segments
Number of Reportable Segments
Due in one year or less, amortized cost
Debt Securities, Available-for-Sale, Amortized Cost, Maturity, Allocated and Single Maturity Date, Year One
Decrease in unrecognized tax benefits is reasonably possible
Decrease in Unrecognized Tax Benefits is Reasonably Possible
Long Term Debt, Exchanged, Amount
Long Term Debt, Exchanged, Amount
Long Term Debt, Exchanged, Amount
Schedule of Equity Method Investments [Table]
Schedule of Equity Method Investments [Table]
Research and development
Research and development
Research and Development Expense [Member]
Nightstar
Nightstar [Member]
Nightstar [Member]
Not designated as hedging instrument
Not Designated as Hedging Instrument [Member]
Accrued expenses and other
Accrued Liabilities [Member]
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Accounts receivable, net
Accounts Receivable, after Allowance for Credit Loss, Current
Government securities Current
Government Securities Current [Member]
Government securities Current.
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]
Revenues from anti-CD20 therapeutic programs
Revenues from anti-CD20 therapeutic programs [Table Text Block]
Revenues from anti-CD20 therapeutic programs
Loss recorded on Samsung Bioepis joint venture
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions
Collaboration agreement term
Collaboration Agreement Term
Collaboration Agreement Term
Gross unrealized losses
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before 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]
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
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.
Gains (losses) on net investment hedge
Accumulated Other Comprehensive Income (Loss), Derivative Qualifying as Hedge, Excluded Component, Including Portion Attributable to Noncontrolling Interest [Member]
Goodwill
Goodwill, beginning of period
Goodwill, end of period
Goodwill
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale [Line Items]
Due in one year or less, estimated fair value
Debt Securities, Available-for-Sale, Fair Value, Maturity, Allocated and Single Maturity Date, Year One
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
Document Transition Report
Document Transition Report
Current portion of contingent consideration obligations
Business Combination, Contingent Consideration, Liability, Current
Solothurn, Switzerland
Solothurn, Switzerland [Member]
Solothurn, Switzerland [Member]
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Collaborative Arrangement and Arrangement Other than Collaborative [Domain]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Numerator:
Net Income (Loss) Attributable to Parent [Abstract]
Facility Type [Axis]
Facility Type [Axis]
Facility Type
Derivative asset, fair value
Derivative Asset, Fair Value, Gross Asset
Income tax assets and liabilities
Increase (Decrease) in Income Taxes Payable
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)
Face amount
Debt Instrument, Face Amount
Significant Other Observable Inputs (Level 2)
Fair Value, Inputs, Level 2 [Member]
Other current assets
Other Assets, Current
Document Quarterly Report
Document Quarterly Report
Government securities Non-current
Government Securities Non-current [Member]
Government Securities Non Current.
Discount rate
Business Combination, Contingent Consideration, Liability, Measurement Input
Liabilities:
Liabilities, Fair Value Disclosure [Abstract]
Other revenues [Abstract]
Other revenues [Abstract]
Other revenues [Abstract]
Summary of roll forward of the changes in goodwill
Schedule of Goodwill [Table Text Block]
Fair Value by Asset Class
Asset Class [Domain]
Asset Class [Domain]
Equity [Abstract]
Equity [Abstract]
Total
Assets, Fair Value Disclosure
Vixotrigine
Vixotrigine [Member]
Vixotrigine
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table]
Gain (loss) on investments in equity securities
Gain (Loss) on Securities [Table Text Block]
Biogen share of co-promotion profits or losses
Biogen share of co-promotion profits or losses
Biogen share of co-promotion profits or losses
Investment in common stock, shares purchased
Investment in common stock, shares purchased
Investment in common stock, shares purchased
Other Consolidated Financial Statement Detail
Additional Financial Information Disclosure [Text Block]
Collaboration profit sharing
Collaboration profit (loss) sharing
Collaboration profit (loss) sharing
Derivative Contract [Domain]
Derivative Contract [Domain]
Estimated future amortization for acquired intangible assets
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]
Diluted earnings per share attributable to Biogen Inc.
Shares used in calculating diluted earnings per share
Weighted Average Number of Shares Outstanding, Diluted
2020 Share Repurchase Program
March 2019 Share Repurchase Program [Member]
March 2019 Share Repurchase Program [Member]
Basic earnings per share attributable to Biogen Inc.
Earnings Per Share, Basic
Entity File Number
Entity File Number
Debt Disclosure [Abstract]
Debt Disclosure [Abstract]
Component of accrued expenses and other
Other Current Liabilities [Member]
(Gain) loss on strategic investments
Increase (Decrease) in Equity Securities, FV-NI
Performance stock units settled in cash
Performance Stock Units Settled in Cash [Member]
Performance Stock Units Settled in Cash [Member]
Sangamo
Sangamo Common Stock [Member]
Sangamo Common Stock [Member]
Net cash flow used in financing activities
Net Cash Provided by (Used in) Financing Activities
Repayment of borrowings
Repayments of Long-term Debt
Manufacturing and other costs
Manufacturing and Other Costs
Manufacturing and Other Costs
Compensation related to share-based payments
Share-based compensation expense
Share-based Payment Arrangement, Expense
Unrealized gains (losses) on securities available for sale
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Investments by Consolidated and Nonconsolidated Entities [Domain]
Investments by Consolidated and Nonconsolidated Entities [Domain]
Common stock, par value $0.0005 per share
Common Stock, Value, Issued
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets Disclosure [Abstract]
Other corporate revenues
Other corporate revenues [Member]
Other corporate revenues [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets [Line Items]
Document Fiscal Year Focus
Document Fiscal Year Focus
Time-vested restricted stock units
Time Vested Restricted Stock Units [Member]
Time vested restricted stock units.
Expected future amortization expense, 2021
Finite-Lived Intangible Asset, Expected Amortization, Year Two
Cash flows, revenue
Cash flows, revenue [Member]
Cash flows, revenue [Member]
Commercial paper
Commercial Paper [Member]
Expense reflected within statements of income
Expense reflected within statements of income
Expense reflected within statements of income
Income tax effect
Share-based Payment Arrangement, Expense, Tax Benefit
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]
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Entity Current Reporting Status
Entity Current Reporting Status
Pre-tax charge, payment of early call premium and write off of remaining unamortized debt issuance costs, net of derivative gain
Pre-tax Charge, Payment of Early Call Premium and Write off of Remaining Unamortized Debt Issuance Costs, Net of Derivative Gain
Pre-tax Charge, Payment of Early Call Premium and Write off of Remaining Unamortized Debt Issuance Costs, Net of Derivative Gain
(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
All Currencies [Domain]
All Currencies [Domain]
Purchases of marketable securities
Payments to Acquire Debt Securities, Available-for-sale
Comprehensive income (loss) attributable to noncontrolling interests, net of tax
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Components of inventories
Inventory, Net [Abstract]
Noncontrolling interests
Stockholders' Equity Attributable to Noncontrolling Interest
Inventory Disclosure [Abstract]
Inventory Disclosure [Abstract]
Collaborative and Other Relationships
Collaborative Arrangement Disclosure [Text Block]
Cash flows from investing activities:
Net Cash Provided by (Used in) Investing Activities [Abstract]
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.
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.
Sangamo Therapeutics, Inc. Agreement
Sangamo Therapeutics, Inc. Agreement [Member]
Sangamo Therapeutics, Inc. Agreement [Member]
Financial Instruments
Cash, Cash Equivalents, and Marketable Securities [Text Block]
Returns
Sales Returns and Allowances [Member]
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
Interest Expense
Interest Expense [Member]
Share Repurchase Program [Axis]
Share Repurchase Program [Axis]
Accounts receivable
Increase (Decrease) in Accounts Receivable
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Total Biogen Inc. shareholders’ equity
Stockholders' Equity Attributable to Parent
Statement of Comprehensive Income [Abstract]
Statement of Comprehensive Income [Abstract]
Warehouse, Utilities and Support Space
Warehouse, Utilities and Support Space [Member]
Warehouse, Utilities and Support Space
Cash settled performance shares
Cash settled performance shares [Member]
Cash settled performance shares [Member]
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
Total liabilities and equity
Liabilities and Equity
Accumulated other comprehensive 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
Income Taxes
Income Tax Disclosure [Text Block]
Entity Address, City or Town
Entity Address, City or Town
Notes payable, carrying value
Notes Payable
Collaboration expense
Employee-related Liabilities, Current
Fair Value Hierarchy and NAV [Axis]
Fair Value Hierarchy and NAV [Axis]
Acquisitions of intangible assets
Payments to Acquire Intangible Assets
Global Licensing Collaboration Agreement, Payment, Achievement of First Commercial Sale Milestones
Global Licensing Collaboration Agreement, Payment, Achievement of First Commercial Sale Milestones
Global Licensing Collaboration Agreement, Payment, Achievement of First Commercial Sale Milestones
Cash flows, operating expenses
Cash flows, operating expenses [Member]
Cash flows, operating expenses [Member]
Parent
Total share-based compensation expense, net of tax
Parent [Member]
Hedging Relationship [Axis]
Hedging Relationship [Axis]
Financial Instrument [Axis]
Financial Instrument [Axis]
Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table]
Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table]
Deferred tax liabilities, increase (decrease) in value
Deferred tax Liabilities, Increase (Decrease) In Value
Deferred tax Liabilities, Increase (Decrease) In Value
December 2019 Share Repurchase Program
December 2019 Share Repurchase Program [Member]
December 2019 Share Repurchase Program [Member]
Other
Other Noncash Income (Expense)
Product, net
Product [Member]
Indefinite-lived Intangible Assets [Axis]
Indefinite-lived Intangible Assets [Axis]
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.
Estimated life, (in years)
Finite-Lived Intangible Asset, Useful Life
Equity Component [Domain]
Equity Component [Domain]
Acquired in-process research and development
Research and Development in Process
Unrealized gains (losses) on securities available for sale, net of tax
OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax
Deferred tax assets, unrecognized tax benefit
Deferred Tax Assets, Valuation Allowance
Reduction in royalty rate payable on commercial sales
Reduction in royalty rate payable on commercial sales
Reduction in royalty rate payable on commercial sales
Schedule of Available-for-sale Securities [Table]
Schedule of Available-for-sale Securities [Table]
Average maturity of marketable securities, months
Average Maturity Of Marketable Securities
Average remaining time to maturity of marketable debt securities, available-for-sale securities.
Property, plant and equipment, net
Property, Plant and Equipment, Net
Expected future amortization expense, 2022
Finite-Lived Intangible Asset, Expected Amortization, Year Three
Entity Tax Identification Number
Entity Tax Identification Number
Foreign currency forward contracts that were entered into to hedge forecasted revenue
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]
Corporate debt securities Current
Corporate Debt Securities Current [Member]
Corporate debt securities Current.
Share-based Payments
Share-based Payment Arrangement [Text Block]
Net income attributable to Biogen Inc.
Net income attributable to Biogen Inc.
Net Income (Loss) Attributable to Parent
Equity Securities, Current
Equity Securities, Current [Member]
Equity Securities, Current
Changes in operating assets and liabilities, net:
Increase (Decrease) in Operating Capital [Abstract]
Accrued expense and other
Total accrued expense and other
Other Liabilities, Current
Schedule of Variable Interest Entities [Table]
Schedule of Variable Interest Entities [Table]
Net distribution to noncontrolling interest
Payments to Noncontrolling Interests
Payments to Noncontrolling Interests
Inventory
Inventory Disclosure [Text Block]
Overview
Business Overview [Policy Text Block]
Describes an overview of the company and its operations.
Other comprehensive income (loss), net of tax
Other Comprehensive Income (Loss), Net of Tax
Investment, Name [Domain]
Investment, Name [Domain]
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]
Share-based Compensation Expense included in consolidated statements of income
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Abstract]
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
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Total current assets
Assets, Current
Current Fiscal Year End Date
Current Fiscal Year End Date
Additional milestone payment
Additional Milestone Payment
Additional milestone payment.
October 2020 Share Repurchase Program
October 2020 Share Repurchase Program [Member]
October 2020 Share Repurchase Program
Comprehensive income (loss) attributable to noncontrolling interests, net of tax
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Net income per share:
Earnings Per Share [Abstract]
Earnings Per Share [Abstract]
ADUHELM
ADUHELM [Member]
ADUHELM
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
State taxes
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent
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]
Unfunded status of postretirement benefit plans
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Dividend yield percentage
Dividend Yield Percentage
Dividend Yield Percentage
Range of durations of foreign currency forward contracts
Derivative, Remaining Maturity
Biogen Idec Inc. shareholders' equity
Stockholders' Equity Attributable to Parent [Abstract]
Developed technology
Developed Technology Rights [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Expected future amortization expense, 2024
Finite-Lived Intangible Asset, Expected Amortization, Year Five
Document Fiscal Period Focus
Document Fiscal Period Focus
Euro
Euro Member Countries, Euro
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table]
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Table]
Global Licensing Collaboration Agreement, Payment, Selection of Targets
Global Licensing Collaboration Agreement, Payment, Selection of Targets
Global Licensing Collaboration Agreement, Payment, Selection of Targets
Business Acquisition, Acquiree [Domain]
Business Acquisition, Acquiree [Domain]
Reconciliation between the U.S. federal statutory tax rate and effective tax rate
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Indefinite lived intangible assets useful life
Indefinite Lived Intangible Assets Useful Life
Indefinite lived intangible assets useful life.
Loss Contingency, Estimate of Possible Loss
Loss Contingency, Estimate of Possible Loss
Entity Filer Category
Entity Filer Category
Share-based compensation expense included in condensed consolidated statements of income
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]
Common stock
Common Stock [Member]
Currency translation adjustments
Accumulated Foreign Currency Adjustment Attributable to Parent [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Product and Service [Domain]
Product and Service [Domain]
Taxes on foreign earnings
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Percent
Due to Related Parties
Due to Related Parties
Reclassification out of Accumulated Other Comprehensive Income
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]
BIIB111
BIIB111 [Member]
BIIB111 [Member]
Strategic investment portfolio
Strategic Investment Portfolio
Strategic investment portfolio.
Deferred tax assets, decrease in value
Deferred Tax Assets, Value, Reduction in Value
Deferred Tax Assets, Value, Reduction in Value
FLIXABI
FLIXABI [Member]
FLIXABI [Member]
BIIB112
BIIB112 [Member]
BIIB112 [Member]
Reclassification out of Accumulated Other Comprehensive Income [Table]
Reclassification out of Accumulated Other Comprehensive Income [Table]
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.
Disaggregation of Revenue [Abstract]
Disaggregation of Revenue [Abstract]
Derivative qualifying as net investment hedge, excluded component
AOCI, Derivative Qualifying as Hedge, Excluded Component, after Tax
Cost
Finite-Lived Intangible Assets, Gross
Loss on research and development contracts terminated with Eisai
Loss on Contract Termination
Other income (expense)
Other Nonoperating Income (Expense) [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Line Items]
Senior notes interest rate
Debt Instrument, Interest Rate, Stated Percentage
Money market funds
Money Market Funds [Member]
Accumulated depreciation
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Facility Location [Axis]
Facility Location [Axis]
-- None. No documentation exists for this element. --
Currency [Axis]
Currency [Axis]
Other
Product and Service, Other [Member]
Issuance of common stock under award plan, shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period
Acquisitions
Business Combination Disclosure [Text Block]
Other income (expense), net
Nonoperating Income (Expense)
Total other income (expense), net
Nonoperating Income (Expense)
Hedging Relationship [Domain]
Hedging Relationship [Domain]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]
Basis of presentation
Basis of Accounting, Policy [Policy Text Block]
Basic earnings per share attributable to Biogen Inc.
Weighted average number of common shares outstanding
Weighted Average Number of Shares Outstanding, Basic
Marketable debt securities
Debt Securities, Available-for-sale [Abstract]
Cost and expenses:
Costs and Expenses [Abstract]
Subsequent Events [Abstract]
Currency translation adjustment
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax
Cash Flow Hedging [Member]
Cash Flow Hedging [Member]
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.
Sage Therapeutics Inc.
Sage Therapeutics Inc. [Member]
Sage Therapeutics Inc.
Equity Method Investment, Ownership Percentage
Percentage of stake in entity maximum
Equity Method Investment, Ownership Percentage
Revenues
Revenue from Contract with Customer [Text Block]
Total equity
Beginning balance
Ending balance
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
Amortization and impairment of acquired intangible assets
Amortization and Impairment of Acquired Intangible Assets
Amortization and Impairment of Acquired Intangible Assets
MS Product Revenues
MS Product Revenues [Member]
MS Product Revenues [Member]
Additional paid-in capital
Additional Paid in Capital
Expected future amortization expense, 2020
Finite-Lived Intangible Asset, Expected Amortization, Year One
Total revenue
Product revenues
Total revenues from anti-CD20 therapeutic programs
Other Revenues
Revenues
Foreign exchange gains (losses), net
Foreign Currency Transaction Gain (Loss), before Tax
Income tax (benefit) expense
Income Tax Expense (Benefit)
Income Tax Expense (Benefit)
Summary of financial assets with original maturities of less than 90 days included within cash and cash equivalents
Cash Equivalents, at Carrying Value [Abstract]
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
Research and development asset [Axis]
Research and development asset [Axis]
Research and development asset [Axis]
Total
Financial and Nonfinancial Liabilities, Fair Value Disclosure
Indefinite-lived Intangible Assets, Major Class Name [Domain]
Indefinite-lived Intangible Assets, Major Class Name [Domain]
Diluted earnings per share attributable to Biogen Inc.
Earnings Per Share, Diluted
Variable Interest Entity [Line Items]
Variable Interest Entity [Line Items]
Local Phone Number
Local Phone Number
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Collaborative Arrangement and Arrangement Other than Collaborative [Axis]
Schedule of Stock by Class [Table]
Schedule of Stock by Class [Table]
Derivative liabilities
Construction Payable
Fair value of contingent consideration obligations
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]
Depreciation
Depreciation
Entity Address, Address Line One
Entity Address, Address Line One
FAMPYRA
FAMPYRA [Member]
FAMPYRA [Member]
Investments, All Other Investments [Abstract]
Investments, All Other Investments [Abstract]
Entity Emerging Growth Company
Entity Emerging Growth Company
Issuance of common stock under stock award plan
Stock Issued During Period, Value, Stock Options Exercised
Cost and Net
Indefinite-lived Intangible Assets (Excluding Goodwill)
Indefinite-lived Intangible Assets (Excluding Goodwill)
Subtotal
Subtotal
Share-based Payment Arrangement, Expense, after Tax
Schedule of Finite-Lived Intangible Assets [Table]
Schedule of Finite-Lived Intangible Assets [Table]
Deferred income taxes
Deferred Income Tax Expense (Benefit)
Derivative liability, fair value
Derivative Liability, Fair Value, Gross Liability
Eisai
Eisai [Member]
Eisai [Member]
Award Type [Axis]
Award Type [Axis]
Global licensing collaboration agreement, shares, purchased (in shares)
Global Licensing Collaboration Agreement, Shares, Purchased
Global Licensing Collaboration Agreement, Shares, Purchased
Prepaid research and development expenses
Prepaid Expense and Other Assets
Accumulated Amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Maximum
Maximum
Maximum [Member]
Noncontrolling interest
Noncontrolling Interest [Member]
Distributor One
Distributor One [Member]
Distributor one.
Retained earnings
Retained Earnings [Member]
Effective tax rate
Effective Income Tax Rate Reconciliation, Percent
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]
Summary of significant accounting policies
Significant Accounting Policies [Text Block]
Net cash flow used in investing activities
Net Cash Provided by (Used in) Investing Activities
Award Type [Domain]
Award Type [Domain]
Basic and diluted earnings per share
Basic And Diluted Earnings Per Share [Abstract]
Basic and diluted earnings per share.
Investment Type Categorization [Domain]
Investments [Domain]
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
Payment of early call premium and write off of remaining unamortized debt issuance costs
Early Call Premium and Write off of Remaining Unamortized Debt Issuance Costs
Early Call Premium and Write off of Remaining Unamortized Debt Issuance Costs
Corporate debt securities
Corporate Debt Securities [Member]
Trading Symbol
Trading Symbol
Other
Goodwill, Other Increase (Decrease)
Accumulated Other Comprehensive Income (Loss) [Table]
Accumulated Other Comprehensive Income (Loss) [Table]
Current portion of notes payable
Notes Payable, Current
Property, Plant and Equipment
Property, Plant and Equipment Disclosure [Text Block]
Treasury stock, at cost
Treasury Stock, Value
Equity Securities, Non-Current
Equity Securities, Non-Current [Member]
Equity Securities, Non-Current
Earnings per Share
Earnings Per Share [Text Block]
Notes payable, fair value
Notes Payable, Fair Value Disclosure
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Current liabilities:
Liabilities, Current [Abstract]
Additional reduction in royalty rate payable on commercial sales
Additional reduction in royalty rate payable on commercial sales
Additional reduction in royalty rate payable on commercial sales
Statutory rate
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent
Entity Shell Company
Entity Shell Company
Research and development
Research and Development Expense (Excluding Acquired in Process Cost)
Research and Development Expense (Excluding Acquired in Process Cost)
Fair Value, Measurements, Recurring
Fair Value, Recurring [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)
Income Tax Contingency [Table]
Income Tax Contingency [Table]
New accounting pronouncements
New Accounting Pronouncements, Policy [Policy Text Block]
Discount rate
Measurement Input, Discount Rate [Member]
Statement of Financial Position [Abstract]
Statement of Financial Position [Abstract]
Revenue from anti-CD20 therapeutic programs
Revenues from anti-cd20 therapeutic programs [Member]
Revenues from anti-cd20 therapeutic programs