Stock-Based Compensation (Stock Option Activity) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009
Stock-Based Compensation [Abstract]
Outstanding at December 31, 2010	13,881,000
Granted	1,074,000	1,103,000	603,000
Exercised	(4,734,000)
Forfeited or expired	(3,954,000)
Outstanding at December 31, 2011	6,267,000	13,881,000
Exercisable at December 31, 2011	4,256,000	12	17
Options expected to vest	2,011,000
Weighted average exercise price of options outstanding at December 31, 2010	$ 17
Granted	$ 18
Exercised	$ 15
Forfeited or expired	$ 22
Weighted average exercise price of options outstanding at December 31, 2011	$ 15	$ 17
Weighted average exercise price of options exercisable at December 31, 2011	$ 15	$ 17	$ 18
Weighted average exercise price of options expected to vest	$ 17
Weighted average remaining life of options outstanding at December 31, 2011, years	4.6
Weighted average remaining life of options exercisable at December 31, 2011, years	2.7
Weighted average remaining life of options expected to vest, years	8.6
Aggregate intrinsic value of options outstanding at December 31, 2011	$ 41
Aggregate intrinsic value of options exercisable at December 31, 2011	31
Aggregate intrinsic value of options expected to vest	$ 10

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The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of vested portions of options outstanding and currently exercisable under the option plan as of the balance sheet date.

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

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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 weighted average period between the balance sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

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As of the balance sheet date, the total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of fully vested and expected to vest options outstanding.

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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 weighted-average period between the balance sheet date and expiration date for fully vested and expected to vest options outstanding, which may be expressed in a decimal value for number of years.

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The weighted average remaining life of the exercisable stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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

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