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The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

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The combined weighted average exercise price associated with stock options during the period that have either lapsed or been forfeited.

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

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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 stock options awarded under the plan during the reporting 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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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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As of the balance sheet date, the number of shares into which fully vested and expected to vest stock options outstanding can be converted under the option plan.

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As of the balance sheet date, the weighted-average exercise price for outstanding stock options that are fully vested or expected to vest.

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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Common Stock (Schedule Of Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010 31.70 - $16.22 [Member]	Dec. 31, 2009 31.70 - $16.22 [Member]	Dec. 31, 2008 31.70 - $16.22 [Member]	Dec. 31, 2009 31.18 - $31.18 [Member]	Dec. 31, 2009 29.89 - $16.22 [Member]	Dec. 31, 2010 32.28 - $30.32 [Member]	Dec. 31, 2011 31.18 - $16.22 [Member]	Dec. 31, 2010 31.18 - $16.22 [Member]	Dec. 31, 2011 32.28 - $16.22 [Member]	Dec. 31, 2010 32.28 - $16.22 [Member]	Dec. 31, 2011 54.79 -$38.12 [Member]	Dec. 31, 2011 46.97 -$16.22 [Member]	Dec. 31, 2011 54.79 -$16.22 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Option, Number of shares, beginning balance	6,594,950	8,802,450	8,116,326
Granted, Number of Shares	2,894,500	94,000	2,635,000
Exercised, Number of Shares	(1,563,255)	(2,000,250)	(1,582,376)
Cancelled, Number of Shares	(367,250)	(301,250)	(366,500)
Outstanding Option, Number of shares, ending balance	7,558,945	6,594,950	8,802,450
Outstanding Option, Average Option Price, beginning balance	$ 25.16	$ 25.03	$ 22.68
Granted, Average Option Price	$ 43.66	$ 30.40	$ 31.18
Exercised, Average Option Price	$ 26.38	$ 24.87	$ 23.71
Cancelled, Average Option Price	$ 32.60	$ 24.91	$ 22.84
Outstanding Option, Average Option Price, ending balance	$ 31.63	$ 25.16	$ 25.03
Outstanding options vested and exercisable, Number of Shares	2,979,945
Outstanding options vested and exercisable, Average Option Price	$ 23.82
Range, High				$ 31.70	$ 31.70	$ 31.70	$ 31.18	$ 29.89	$ 32.28	$ 31.18	$ 31.18	$ 32.28	$ 32.28	$ 54.79	$ 46.97	$ 54.79
Range, Low				$ 16.22	$ 16.22	$ 16.22	$ 31.18	$ 16.22	$ 30.32	$ 16.22	$ 16.22	$ 16.22	$ 16.22	$ 38.12	$ 16.22	$ 16.22