Basis of Presentation and Accounting Policies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Reconciled Basic and Diluted EPS
Net income	$ 248.7	$ 199.7	$ 180.3	$ 198.1	$ 215.3	$ 203.7	$ 175.9	$ 161.4	$ 826.8	$ 756.3	$ 737.0
Less: Allocation to participating securities									(1.1)	(1.1)	(1.4)
Net income available to common shareowners									$ 825.7	$ 755.2	$ 735.6
Basic weighted average outstanding shares									138.0	139.2	141.5
Effect of dilutive securities
Stock options									1.5	1.5	1.6
Performance shares									0.2	0.2	0.3
Diluted weighted average outstanding shares									139.7	140.9	143.4
Basic earnings per share:
Basic	$ 1.81	$ 1.44	$ 1.30	$ 1.43	$ 1.55	$ 1.46	$ 1.25	$ 1.16	$ 5.98	$ 5.43	$ 5.20
Diluted earnings per share:
Diluted	$ 1.79	$ 1.43	$ 1.28	$ 1.41	$ 1.53	$ 1.45	$ 1.24	$ 1.14	$ 5.91	$ 5.36	$ 5.13