Stock-Based Compensation (Summary Of Activity In Corporation's Active Stock Plans) (Details) (USD $)	9 Months Ended
Sep. 30, 2011
Beginning Balance, Shares Available for Grant	2,759,347
Beginning Balance, Director Deferred Stock Units Outstanding	16,515
Granted, Shares Available for Grant	(5,577)
Granted, Director Deferred Stock Units Outstanding	5,577
Granted, Number of Shares
Stock options exercised, Shares Available for Grant
Stock options exercised, Director Deferred Stock Units Outstanding
Stock awards vested, Shares Available for Grant
Stock awards vested, Director Deferred Stock Units Outstanding
Forfeited, Shares Available for Grant	54,125
Forfeited, Director Deferred Stock Units Outstanding
Ending Balance, Shares Available for Grant	2,807,895
Ending Balance, Director Deferred Stock Units Outstanding	22,092
Stock Options Outstanding [Member]
Beginning Balance, Number of Shares	4,383,885
Beginning Balance, Weighted-Average Exercise Price	$ 52.08
Granted, Number of Shares
Granted, Weighted-Average Exercise Price
Stock options exercised, Shares Available for Grant
Stock options exercised, Number of Shares	(144,203)
Stock options exercised, Weighted-Average Exercise Price	$ 50.19
Stock awards vested, Number of Shares
Stock awards vested, Weighted-Average Exercise Price
Forfeited, Number of Shares	(54,125)
Forfeited, Weighted-Average Exercise Price	$ 51.49
Ending Balance, Number of Shares	4,185,557
Ending Balance, Weighted-Average Exercise Price	$ 52.15
Non-Vested Stock Awards Outstanding [Member]
Beginning Balance, Number of Shares	227,550
Beginning Balance, Weighted-Average Grant-Date Fair Value	$ 51.10
Granted, Number of Shares
Granted, Weighted-Average Grant-Date Fair Value
Stock options exercised, Shares Available for Grant
Stock options exercised, Number of Shares
Stock options exercised, Weighted-Average Grant-Date Fair Value
Stock awards vested, Number of Shares	(85,420)
Stock awards vested, Weighted-Average Grant-Date Fair Value	$ 50.64
Forfeited, Number of Shares
Forfeited, Weighted-Average Grant-Date Fair Value
Ending Balance, Number of Shares	142,130
Ending Balance, Weighted-Average Grant-Date Fair Value	$ 51.38

Schedule of Recognized Stock Based Compensation Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures Deferred Stock Units Outstanding

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Share Based Compensation Arrangement By Share Based Payment Award Options Deferred Stock Units Outstanding

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Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Deferred Stock Units Outstanding Grants In Period

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Share Based Compensation Arrangement By Share Based Payment Award Options Number Of Shares Available for Grant, Granted

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Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Deferred Stock Units Outstanding

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Share Based Compensation Arrangement By Share Based Payment Award Options Vested And Expected To Vest Exercisable Shares Available for Grant

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Share Based Compensation Arrangement By Share Based Payments Award Grant Deferred Stock Units Outstanding

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The weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect during the reporting period as a result of the occurrence of a terminating event specified in the contractual agreement of the plan.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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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 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 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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The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

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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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The number of exercisable share options (fully vested and expected to vest) that may be converted as of the balance sheet date.

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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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