Commitments and Contingencies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Cash performance unit awards
Commitments and Contingencies
Performance period						5 years
Amount of cash flow performance goals						$ 850.0
Amount of cash flow achieved				319.2
Amount of cash flow expenses accrued				4.0
Maximum payout				1.4
Expense recognized under the amended performance unit awards	0.3
Percentage of performance units vested		50.00%	50.00%
Average stock price period				60 days	60 days
Expense related solely to increase (decrease) in average stock price	9.6
SARs
Commitments and Contingencies
Average stock price period	60 days
Grants approved by committee to employees for cash settled stock appreciation rights (in shares)	1.0				0.4
Grant-date stock price (in dollars per share)	$ 1.85				3.81
Percentage of stock price on grant date	135.00%
SARs - 2011 Awards
Commitments and Contingencies
Amount accrued for awards	1.3
SARs - 2012 Awards
Commitments and Contingencies
Amount accrued for awards	$ 4.5
Minimum | SARs - 2012 Awards
Commitments and Contingencies
Threshold stock price at which SARS will vest (in dollars per share)	$ 2.50