Schedule Of Actual Weighted Average Shares Used In Calculating Earnings Per Share (Detail) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Schedule of Weighted Average Number of Diluted Shares Outstanding [Line Items]
Weighted average shares basic	93.5	89.2	91.4	89.1
stock options/share awards	0.3	0.5	0.3	0.6
equity units	1.3	4.3	2.7	4.3
Weighted average shares diluted	95.1	94.0	94.4	94.0

Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of equity unit purchase agreements using the treasury stock method.

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

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

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-Name Emerging Issues Task Force (EITF)

-Number 07-4

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

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

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