Stock-Based Compensation - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Earlier authorized shares under stock based compensation	25,500,000
Remaining shares available for future grants under the Plan	54.382
Total stock-based compensation compensation arrangements under the Plan	$ 17	$ 12
Total income tax benefit stock-based compensation arrangements under the Plan	5	3
Period of option vested over grant date	Options generally vest over a three-year period from the grant date.
Performance based restricted stock awards vested, number of years	3 years
Description of performance goal	Performance against the ROC goal is determined by comparing the performance of the Company's actual ROC performance average for each of the three years of the performance period against the ROC goal set by the Company's Compensation Committee.
TSR Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based restricted stock awards granted in percent	50.00%
ROC Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance based restricted stock awards granted in percent	50.00%
Stock options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option granted	2,819,806
Stock option granted fair value	$ 24.10
Stock option granted, exercise price	$ 69.33
Restricted stock and restricted stock units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted	540,194
Restricted stock granted fair value	$ 69.33
Performance-base restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation compensation arrangements under the Plan	$ 8
Performance-base restricted stock [Member] \| Senior Management Employees [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted	0
Performance-base restricted stock [Member] \| Senior Management Employees [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock granted	398,160
Restricted stock awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Period of option vested over grant date	Restricted stock and restricted stock units were granted February 15, 2013 and vest on the third anniversary of the date of grant, except for a special grant of 16,352 restricted stock units which vest on the second anniversary of the date of grant (subject to the satisfaction of a performance condition)

Earlier authorized shares under stock based compensation.

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Performance based restricted stock awards granted in percent.

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- Definition

Remaining shares available for future grants under the Plan.

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- Definition

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

+ References

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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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- Definition

General descriptive information regarding an arrangement under which employees and directors receive: (a) awards of equity shares, equity share options, or other equity instruments; or (b) the entity incurs liabilities to them: (1) in amounts based, at least in part, on the price of the entity's shares or other equity instruments; or (2) that require or may require settlement by issuance of the entity's shares. Such an arrangement is usually provided to employees and directors to compensate them, provide performance incentives to them, and to attract or retain their services. May also include pertinent information particular to a plan that is not elsewhere specified in the taxonomy.

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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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- Definition

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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- Definition

Net number of share options (or share units) granted during the period.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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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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