Stock Option Plans and Share-Based Compensation Stock option rollforward YTD (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance	1,107,858
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 7.0
Options, shares outstanding- Period start	4,470,000
Options, Outstanding, Wtd Avg Exercise Price - Period start	$ 14.06
Options, Shares Granted in Period	204,000
Options, Grants in Period, Wtd Avg Exercise Price	$ 17.06
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(470,000)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 10.67
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	(12,000)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Forfeitures in Period, Weighted Average Exercise Price	$ 14.26
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	(23,000)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Expirations in Period, Weighted Average Exercise Price	$ 22.44
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	2,971,000
Options, shares outstanding- Period end	4,169,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 14.44
Options, Outstanding, Wtd Avg Exercise Price - Period end	$ 14.54

Aggregate number of common shares reserved for future issuance.

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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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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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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 price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

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

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