Basis of Presentation and Accounting Policies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Reconciled Basic and Diluted EPS
Net income	$ 161.4	$ 183.3
Less: Allocation to participating securities	(0.2)	(0.4)
Net income available to common shareowners	$ 161.2	$ 182.9
Basic weighted average outstanding shares	139.3	141.8
Effect of dilutive securities
Stock options	1.6	1.7
Performance shares	0.3	0.4
Diluted weighted average outstanding shares	141.2	143.9
Earnings Per Share, Basic [Abstract]
Basic	$ 1.16	$ 1.29
Earnings Per Share, Diluted [Abstract]
Diluted	$ 1.14	$ 1.27