Income Taxes (Details)	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Reconciliation between the U.S. federal statutory tax rate and effective tax rate
Statutory rate	21.00%	21.00%	21.00%	21.00%
State taxes	0.90%	0.90%	0.60%	0.70%
Taxes on foreign earnings	(3.00%)	(5.00%)	(3.60%)	(4.70%)
Credits and net operating loss utilization	(2.30%)	(1.50%)	(1.30%)	(1.00%)
Purchased intangible assets	2.90%	0.40%	0.80%	0.40%
Denmark assets held for sale	0.00%	0.00%	0.00%	1.50%
Internal reorganization of certain intellectual property rights	0.00%	(1.50%)	0.00%	(2.10%)
TECFIDERA impairment	3.50%	0.00%	1.90%	0.00%
GILTI	2.20%	1.60%	1.30%	1.60%
Swiss tax reform	0.00%	(3.10%)	0.00%	(1.00%)
Permanent items	(0.60%)	(0.10%)	0.00%	0.20%
Other	0.50%	(0.80%)	0.20%	(0.30%)
Effective tax rate	25.10%	11.90%	20.90%	16.30%

Effective Income Tax Rate Reconciliation Change in Foreign Tax Rate Percent

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Effective Income Tax Rate Reconciliation, Intellectual Property Rights Reorganization

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Effective Tax Rate Reconciliation, GILTI tax

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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Percentage of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operations, attributable to disposition of asset. Includes, but is not limited to, intra-entity transfer of asset other than inventory.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to statutory income tax expense (benefit) outside of the country of domicile.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits.

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