Shareholders' Equity (Stock Option Plans) (Details) - $ / shares shares in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of Shares
Beginning balance (in shares)	15,706	15,813	16,712
Granted (in shares)	4,529	2,480	2,468
Exercised (in shares)	(1,563)	(2,243)	(3,232)
Expired or canceled (in shares)	(177)	(344)	(135)
Ending balance (in shares)	18,495	15,706	15,813
Weighted Average Price
Beginning balance (in USD per share)	$ 47.43	$ 41.84	$ 37.63
Granted (in USD per share)	56.54	64.04	49.94
Exercised (in USD per share)	28.83	25.27	25.93
Expired or canceled (in USD per share)	55.76	55.07	49.58
Ending balance (in USD per share)	$ 51.15	$ 47.43	$ 41.84
Total options that were exercisable (in shares)	6,641	8,214
Exercisable shares, weighted avg. price (in USD per share)	$ 39.35
Available for future grant as of December 31, 2018 (in shares)	15,287

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Net number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of share options (or share units) exercised during the current period.

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