Supplemental Financial Information - Reconciliation of Basic and Diluted Shares (Detail) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation Of Basic Weighted Average Shares To Diluted Weighted Average Shares [Line Items]
Basic shares	559,459	585,704	638,998
Dilutive effect of stock options, employee stock purchase rights and restricted stock unit awards	21,089	15,189	7,326
Diluted shares	580,548	600,893	646,324

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-Name Emerging Issues Task Force (EITF)

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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