Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares excluded from computation of earnings per share				8.6
Earnings Per Share Reconciliation [Abstract]
Net income	$ 249.8	$ 221.4	$ 602.6	$ 511.8
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Denominator for basic earnings per share - weighted average common shares	371.8	366.8	370.4	365.9
Employee stock awards (shares)	4.1	3.5	4.0	3.4
Denominator for diluted earnings per share - adjusted weighted average common shares	375.9	370.3	374.4	369.3
Basic net income per common share (in dollars per share)	$ 0.67	$ 0.60	$ 1.63	$ 1.40
Net income per common share assuming dilution (in dollars per share)	$ 0.66	$ 0.60	$ 1.61	$ 1.39

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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