Earnings Per Share (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Numerator:
Net income	$ 787.8	$ 28.7	$ 856.2	$ 36.0
Interest expense and amortization of issuance costs associated with convertible senior notes	9.5	0	27.1	0
Numerator for diluted earnings per share after assumed conversions	$ 797.3	$ 28.7	$ 883.3	$ 36.0
Denominator:
Denominator for basic earnings per share - weighted average common shares	318.8	318.7	317.6	319.0
Effect of dilutive securities:
Employee stock awards	2.9	0.3	1.8	0.3
Convertible senior notes	38.3	0	38.3
Denominator for diluted earnings per share - adjusted weighted average common shares	360.0	319.0	357.7	319.3
Earnings (Loss) Per Share [Abstract]
Number of shares excluded from computation of earnings per share	4.0	9.6

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

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The after-tax amount of interest recognized in the period associated with any convertible debt.

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Net Income or Loss Available to Common Stockholders plus adjustments resulting from the assumption that dilutive convertible securities were converted, options or warrants were exercised, or that other shares were issued upon the satisfaction of certain conditions.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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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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