Condensed Consolidated Statement of Changes in Stockholders' Equity (Parenthetical) (USD $) In Millions, except Share data	9 Months Ended
Sep. 30, 2011
Condensed Consolidated Statement of Changes in Stockholders' Equity
Issuance of common stock for stock options, shares	111,792
Issuance of common stock for share awards, shares	641,733
Issuance of common stock for employee stock unit awards, shares	271,623
Issuance of common stock for stock options, share awards and employee stock unit awards, tax benefit decrease (in dollars)	$ 2.6
Issuance of common stock for the employee stock purchase plan, shares	108,622
Shares withheld for net settlements of share-based awards, shares	307,953
Purchase of common stock for treasury, shares	1,964,500

Increase (decrease) in number of shares held in treasury during the period as a result of the settlement of share-based awards.

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Issuance of common stock for employee stock unit awards.

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Tax benefit associated with any equity-based compensation plan other than an employee stock ownership plan (ESOP). The tax benefit results from the deduction by the entity on its tax return for an award of stock that exceeds the cumulative compensation cost for common stock or preferred stock recognized for financial reporting. Includes any resulting tax benefit that exceeds the previously recognized deferred tax asset (excess tax benefits).

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.

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

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Number of shares that have been repurchased during the period and are being held in treasury.

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