Basis of Presentation and Accounting Policies (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reconciled Basic and Diluted EPS
Net income	$ 185.5	$ 214.2
Less: Allocation to participating securities	(0.2)	(0.3)
Net income available to common shareowners	$ 185.3	$ 213.9
Basic weighted average outstanding shares	131.8	135.6
Effect of dilutive securities
Stock options	0.8	1.2
Performance shares	0.0	0.1
Diluted weighted average outstanding shares	132.6	136.9
Earnings Per Share, Basic [Abstract]
Basic	$ 1.41	$ 1.58
Earnings Per Share, Diluted [Abstract]
Diluted	$ 1.40	$ 1.56