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Income Taxes (Reconciliation Of U.S. Federal Statutory Rate To Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	21.00%
State taxes, net of federal tax	1.70%	2.40%	2.10%
Foreign operations	0.70%	1.70%	(0.90%)
Research tax credit	(1.70%)	(1.70%)	(1.50%)
Foreign-derived intangible tax benefit	(0.40%)	(2.10%)	(2.40%)
U.S. minimum tax on foreign income	0.50%	1.00%	1.50%
Uncertain tax positions	(1.70%)	0.80%	0.70%
Taxes applicable to prior years	(1.40%)	(0.30%)	(0.70%)
Change in U.S. tax rate	(0.00%)	(0.00%)	(2.00%)
Other items and adjustments	(0.40%)	0.50%	1.30%
Effective income tax rate	18.30%	23.30%	19.10%

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by multiplying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to the deduction for the foreign derived intangible income deduction.

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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 the global intangible low-taxed income (GILTI) provision, net of foreign tax credit, pursuant to the Tax Cuts and Jobs Act ("Tax Reform Act").

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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 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 changes in the income tax rates.

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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 other adjustments.

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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 income tax contingencies. Includes, but not limited to, domestic tax contingency, foreign tax contingency, state and local tax contingency, and other contingencies.

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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 research tax credit.

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