Receivables, net - Summary of Analysis of Allowance for Doubtful Trade Accounts Receivables (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at Beginning of Period	$ 21.9	$ 14.1	$ 4.3
Charged to Costs and Expenses	15.5	7.8	9.8
Deductions	0	0	0
Other Adjustments	0	0	0
Balance at End of Period	$ 37.4	$ 21.9	$ 14.1