Shareholders' Equity (Stock Option Plans) (Details) - $ / shares shares in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance	19,237	20,461	23,637
Balance, weighted avg. price	$ 28.71	$ 25.26	$ 22.58
Granted	2,310	2,005	2,293
Granted, weighted avg. price	$ 49.57	$ 53.34	$ 40.05
Exercised	(1,809)	(2,927)	(5,261)
Exercised, weighted avg. price	$ 24.82	$ 21.44	$ 19.52
Expired or canceled	(1,669)	(302)	(208)
Expired or canceled, weighted avg. price	$ 30.86	$ 28.97	$ 28.83
Balance	18,069	19,237	20,461
Balance, weighted avg. price	$ 31.57	$ 28.71	$ 25.26
Total options that were exercisable	6,692	8,508	10,295
Exercisable shares, weighted avg. price	$ 21.28
Available for future grant as of December 31, 2016	25,156

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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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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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