Earnings Per Share (Details) shares in Millions	12 Months Ended
	Sep. 30, 2015 $ / shares shares	Sep. 30, 2014 shares	Sep. 30, 2013 shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)	1.1	0.6
Debt Instrument, Convertible, Stock Price Trigger, Range Two | TEU Senior Amortizing Notes Maturing July 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt Instrument, Convertible, Conversion Ratio	1.40746
Debt Instrument, Convertible, Stock Price Trigger | $ / shares	$ 17.75
Stock Compensation Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)			0.6
Equity Unit Purchase Agreements
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share (shares)			7.9