Earnings Per Share (Details) In Millions	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Common share data used for computing the basic and diluted earnings per share
Number of common shares outstanding at end of period	461.2	475.7	461.2	475.7
Effect of using weighted average common shares outstanding	7.1	1.6	11.5	6.0
Weighted average basic common shares outstanding	468.3	477.3	472.7	481.7
Dilutive effect of equity-based compensation awards and other contingently issuable shares	1.4	3.7	1.8	3.2
Weighted average diluted common shares outstanding	469.7	481.0	474.5	484.9
Potentially issuable shares	17.3	14.7	17.3	14.7
Number of anti-dilutive potentially issuable shares excluded from diluted common shares outstanding	9.9	0.2	6.4	0.2

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) in the future that were not included in the computation of diluted EPS because to do so would increase EPS amounts or decrease loss per share amounts for the period presented.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 128

-Paragraph 13, 14

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 128

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 128

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Total number of shares of common stock held by shareholders. May be all or portion of the number of common shares authorized. These shares represent the ownership interest of the common shareholders. Excludes common shares repurchased by the entity and held as Treasury shares. Shares outstanding equals shares issued minus shares held in treasury. Does not include common shares that have been repurchased.

+ References

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-Name Regulation S-X (SX)

-Number 210

-Section 02

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- Definition

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

+ References

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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The average number of shares issued and outstanding that are used in calculating diluted EPS, determined based on the timing of issuance of shares in the period.

+ References

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-Name Statement of Financial Accounting Standard (FAS)

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

+ References

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