Fair Value Measurement (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Millions	Jun. 30, 2011	Sep. 30, 2010	Jun. 30, 2010
Fair Value Inputs Level-1 [Member] | Commodity Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	$ 0.6	$ 1.1	$ 0.4
Derivative financial instruments, liabilities	(12.2)	(49.4)	(25.4)
Fair Value Inputs Level-1 [Member] | Foreign currency contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0	0	0
Derivative financial instruments, liabilities	0	0	0
Fair Value Inputs Level-1 [Member] | Interest Rate Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0
Derivative financial instruments, liabilities	0	0	0
Fair Value Inputs Level-2 [Member] | Commodity Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	10.1	10.7	3.2
Derivative financial instruments, liabilities	(11.6)	(20.3)	(18.1)
Fair Value Inputs Level-2 [Member] | Foreign currency contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0	0.8	16.9
Derivative financial instruments, liabilities	(6.1)	(2.9)	0
Fair Value Inputs Level-2 [Member] | Interest Rate Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	5.0
Derivative financial instruments, liabilities	(3.6)	(18.5)	(16.4)
Fair Value, Inputs, Level 3 [Member] | Commodity Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0	0	0
Derivative financial instruments, liabilities	0	0	0
Fair Value, Inputs, Level 3 [Member] | Foreign currency contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0	0	0
Derivative financial instruments, liabilities	0	0	0
Fair Value, Inputs, Level 3 [Member] | Interest Rate Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0
Derivative financial instruments, liabilities	0	0	0
Commodity Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	10.7	11.8	3.6
Derivative financial instruments, liabilities	(23.8)	(69.7)	(43.5)
Foreign currency contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	0	0.8	16.9
Derivative financial instruments, liabilities	(6.1)	(2.9)	0
Interest Rate Contracts [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative financial instruments, assets	5.0
Derivative financial instruments, liabilities	$ (3.6)	$ (18.5)	$ (16.4)