Derivative Instruments and Hedging Activities - Schedule of Derivative Assets, Liabilities and the Effects of Offsetting (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Derivatives, Fair Value
Derivative financial assets	$ 45.4	$ 26.3	[1]
Derivative asset offset amount, net	(18.4)	(2.1)	[1]
Total derivative assets - net	27.0	24.2	[1]
Derivative financial liabilities	75.2	57.5	[1]
Derivative liability offset amount, net	18.4	2.1	[1]
Total derivative liabilities - net	(56.8)	(55.4)	[1]
Designated as Hedging Instruments
Derivatives, Fair Value
Derivative financial assets	17.8	18.9	[1]
Derivative financial liabilities	(26.4)	(43.9)	[1]
Designated as Hedging Instruments | Commodity Contracts
Derivatives, Fair Value
Derivative financial assets	2.8	18.0	[1]
Derivative financial liabilities	(5.3)	(4.5)	[1]
Designated as Hedging Instruments | Foreign Currency Contracts
Derivatives, Fair Value
Derivative financial assets	12.8	0.9	[1]
Derivative financial liabilities	(0.1)	(7.2)	[1]
Designated as Hedging Instruments | Cross Currency Contracts
Derivatives, Fair Value
Derivative financial assets	2.1	0	[1]
Derivative financial liabilities	0	(1.2)	[1]
Designated as Hedging Instruments | Interest Rate Contracts
Derivatives, Fair Value
Derivative financial assets	0.1	0	[1]
Derivative financial liabilities	(21.0)	(31.0)	[1]
Not Designated as Hedging Instruments | Commodity Contracts
Derivatives, Fair Value
Derivative financial assets	25.9	7.4	[1]
Derivative financial liabilities	46.6	6.9	[1]
Accounted for Under ASC 980 | Commodity Contracts
Derivatives, Fair Value
Derivative financial assets	1.7	0	[1]
Derivative financial liabilities	$ (2.2)	$ (6.7)	[1]

[1] Certain immaterial amounts have been revised to correct the classification of derivatives.