Stock-Based Compensation (Stock Option Activity) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended
Sep. 30, 2014
Stock option activity [Abstract]
Options outstanding	723,697
Exercised	(232,751)
Forfeitures or expired	(10,730)
Options outstanding	480,216
Options exercisable	480,216
Weighted Average Exercise Price Per Share - Options outstanding	$ 42.60
Weighted Average Exercise Price - Exercised	$ 41.44
Weighted Average Exercise Price Per Share - Forfeitured or expired	$ 39.41
Weighted Average Exercise Price Per Share - Options outstanding	$ 43.24
Weighted Average Exercise Price - Options exercisable	$ 43.24
Aggregate Intrinsic Value - Options outstanding	$ 16
Aggregate Intrinsic Value - Options exercisable	$ 16

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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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For presentations that combine terminations, 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 or that expired.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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

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

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