Equity-Based Compensation (Stock Options And Stock Appreciation Rights Activity) (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning, shares	7,709	10,983
Exercised, shares	(1,459)	(1,028)
Forfeited or expired, shares	(612)	(2,246)
Outstanding at end, shares	5,638	7,709
Exercisable, shares	5,509
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning, weighted average exercise price	$ 57.58	$ 53.37	$ 51.49
Exercised, weighted average exercise price	$ 38.09	$ 40.52
Forfeited or expired, weighted average exercise price	$ 51.03	$ 50.06
Outstanding at end, weighted average exercise price	$ 57.58	$ 53.37	$ 51.49
Exercisable, weighted average exercise price	$ 58.48
Weighted average remaining contractual term, years	2 years 2 months 12 days
Outstanding at end, aggregate intrinsic value	$ 11
Exercisable, weighted average remaining contractual term, years	2 years 2 months 12 days
Exercisable, aggregate intrinsic value	$ 8

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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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Weighted average price of options that were either forfeited or expired.

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

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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 remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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

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