Accrued expenses on funding commitment related to clinical research.

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- Definition

Commitments And Contingencies.

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Cumulative sales level

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- Definition

Deferred Tax Liabilities, Decrease Due to Overpayment

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- Definition

Future contingent payment for annual worldwide net sales that exceed $2.0 billion

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- Definition

Future contingent payment for annual worldwide net sales up to $2.0 billion

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Future contingent payment threshold

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- Definition

Percentage of royalties as per collaboration.

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Potential future milestone payments commitment to third party approximately.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

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Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiaries and other recognized entities not within the country of domicile of the entity.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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No definition available.

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Amount recognized for uncertainty in income taxes classified as current.

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Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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Commitments and Contingencies (Details Textual) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2006	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2013	Apr. 02, 2013
Business Acquisition [Line Items]
Maximum contingent consideration in the form of development and approval milestones	$ 1,000.0		$ 1,000.0
Increase to goodwill			1,080.1	$ 1,267.3
Potential future milestone payments commitment, approximately	5,000.0		5,000.0
Cancellable future commitments	655.0		655.0
Commitments And Contingencies (Textual)
Accrued expenses	27.0		27.0
Liabilities associated with uncertain tax positions	117.7		117.7
Lease rent expense which terminates at various dates through 2028			64.5	65.3	$ 68.7
TYSABRI
Business Acquisition [Line Items]
Future contingent payment for annual worldwide net sales up to $2.0 billion											18.00%
Future contingent payment threshold											$ 2,000.0
Future contingent payment for annual worldwide net sales that exceed $2.0 billion											25.00%
Fumapharm AG
Business Acquisition [Line Items]
Amount paid in cash						$ 220.0
Solothurn
Business Acquisition [Line Items]
Cancellable future commitments	111.0		111.0
TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Maximum contingent consideration in the form of development and approval milestones										$ 15.0
Increase to goodwill			1,200.0	1,500.0
Fifteen billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Cumulative sales level		$ 15,000.0		15,000.0
Sixteen billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Increase to goodwill		600.0
Cumulative sales level		16,000.0		16,000.0
Seventeen billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Cumulative sales level									$ 17,000.0
Eighteen billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Cumulative sales level								$ 18,000.0
Nineteen billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Increase to goodwill			1,500.0
Cumulative sales level							$ 19,000.0
Twenty billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Increase to goodwill	300.0
Each additional one billion up to twenty billion \| TECFIDERA \| Fumapharm AG
Business Acquisition [Line Items]
Cumulative sales level	20,000.0		20,000.0
Development Milestones
Business Acquisition [Line Items]
Potential future milestone payments commitment, approximately	700.0		700.0
Regulatory Milestones [Member]
Business Acquisition [Line Items]
Potential future milestone payments commitment, approximately	1,800.0		1,800.0
Commercial Milestones [Member]
Business Acquisition [Line Items]
Potential future milestone payments commitment, approximately	2,500.0		2,500.0
2017 Tax Act
Business Acquisition [Line Items]
Transition toll tax liabilities	$ 697.0	$ 989.6	697.0	$ 989.6
Deferred tax liabilities, decrease due to overpayment			$ 150.0
Ionis Pharmaceuticals \| Minimum \| SPINRAZA
Business Acquisition [Line Items]
Percentage Of Royalties As Per Collaboration			11.00%
Ionis Pharmaceuticals \| Maximum \| SPINRAZA
Business Acquisition [Line Items]
Percentage Of Royalties As Per Collaboration			15.00%