Stock Option Information (Detail) (Employee Stock Option, USD $)	9 Months Ended
Sep. 30, 2011
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance	9,690,000
Granted	891,000
Exercised	(24,000)
Forfeited or expired	(1,155,000)
Ending balance	9,402,000
Beginning balance	$ 36.59
Granted	$ 33.98
Exercised	$ 26.87
Forfeited or expired	$ 33.85
Ending balance	$ 36.71

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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