EARNINGS PER COMMON SHARE (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Basic EPS:
Net Income	$ 94.4	$ 52.2	$ 141.5	$ 87.8
Less: Income allocated to participating securities	0.3	0.2	0.5	0.3
Net Income Available to Common Shareholders	94.1	52.0	141.0	87.5
Weighted Average Shares Outstanding, Basic (in Shares)	43.1	32.6	43.1	32.6
Basic Earnings Per Share of Common Stock (in dollars per share)	$ 2.18	$ 1.59	$ 3.27	$ 2.68
Diluted EPS:
Net Income	94.4	52.2	141.5	87.8
Less: Income allocated to participating securities	0.3	0.2	0.5	0.3
Net Income Available to Common Shareholders	$ 94.1	$ 52.0	$ 141.0	$ 87.5
Weighted Average Shares Outstanding, Basic (in Shares)	43.1	32.6	43.1	32.6
Dilutive Effect of Stock Options, Restricted Stock and Restricted Stock Units (in shares)	0.1	0	0.1	0.1
Weighted Average Diluted Shares (in shares)	43.2	32.6	43.2	32.7
Diluted Earnings Per Share of Common Stock (in dollars per share)	$ 2.18	$ 1.59	$ 3.26	$ 2.68
Restricted stock and stock units subject to performance and/or market conditions
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding shares excluded from calculation of diluted EPS (in shares)	0.4	0.3