Stock-Based Compensation (Stock Based Compensation Activity) (Detail) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Exercise Price, Balance at January 1, 2012	7.90
Granted at fair market value
Weighted Average Exercise Price, Vested/exercised	0.79
Weighted Average Exercise Price, Canceled	27.06
Weighted Average Exercise Price, Balance at March 31, 2012	2.79
Number of Options, Balance at January 1, 2012	3,432
Number of Options, Vested/exercised	(603)
Number of Options, Canceled	(772)
Number of Options, Balance	2,057
Options outstanding, intrinsic value	26
In-the-money' stock options (in number of options)	2,000
Stock options exercisable	2,000
RSU [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Average Grant Price, Balance	12.74
Weighted Average Grant Price, Granted at fair market value	14.44
Weighted Average Grant Price, Vested/exercised	12.61
Weighted Average Grant Price, Canceled	13.06
Weighted Average Grant Price, Balance	13.65
Number of RSUs, Balance	2,998
Number of RSUs, Granted at fair market value	1,809
Number of RSUs, Vested/exercised	(1,250)
Number of RSUs, Canceled	(19)
Number of RSUs, Balance	3,538
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of performance based stock vested	615
Number of performance based stock vested, intrinsic value	8
Options outstanding, intrinsic value	54
Aggregate unrecognized compensation expense related to awards	30
Time-based restricted stock units outstanding	1,471
Number of performance-based and market-based stock units outstanding	2,067
Restricted Stock Units (RSUs) [Member] \| Time-based vesting schedule [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of RSUs, Granted at fair market value	835	648
Share-based compensation,RSUs eligible to vest	1

Number of performance based and market based stock units outstanding

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Number of performance based stock vested during the period.

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Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Intrinsic Value Amount

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- Definition

The total number of options outstanding at the period-end that have an intrinsic value.

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Time based restricted stock units outstanding

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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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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 as a result of the occurrence of a terminating event.

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The number of grants made 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 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).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

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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-SubTopic 10

-Section 50

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-Paragraph A240

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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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 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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- Definition

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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- Definition

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

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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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

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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- Definition

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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Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

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- Definition

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

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