Disclosures About Derivative Instruments and Hedging Activities - Effects of Derivative Instruments on the Condensed Consolidated Statements of Income and Changes in AOCI and Noncontrolling Interest (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	$ (22.2)	$ 11.4	$ (9.3)	$ 13.7
Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI and noncontrolling interests	5.9	10.2	53.9	3.4
Gain (loss) reclassified from AOCI and noncontrolling interest into income	34.7	(29.4)	50.5	(50.3)
Commodity Contracts | Derivatives Not Designated as Hedging Instruments | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	(22.2)	11.5	(9.4)	13.8
Commodity Contracts | Derivatives Not Designated as Hedging Instruments | Operating Expenses / Other Income
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	0	0.1	0.1	0.1
Commodity Contracts | Cash Flow Hedges | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI and noncontrolling interests	7.8	(0.4)	61.2	(4.5)
Gain (loss) reclassified from AOCI and noncontrolling interest into income	39.9	(25.3)	62.2	(43.2)
Foreign Currency Contracts | Derivatives Not Designated as Hedging Instruments | Other Income
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	0	(0.2)	0	(0.2)
Foreign Currency Contracts | Cash Flow Hedges | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI and noncontrolling interests	(0.2)	2.6	(2.7)	(1.1)
Gain (loss) reclassified from AOCI and noncontrolling interest into income	(1.4)	(0.6)	(3.5)	(0.1)
Cross Currency Interest Rate Contract | Cash Flow Hedges | Interest Expense
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI and noncontrolling interests	0.1	0	(1.1)	0
Gain (loss) reclassified from AOCI and noncontrolling interest into income	0.2	0	(0.1)
Interest Rate Contracts | Cash Flow Hedges | Interest Expense / Other Income
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI and noncontrolling interests	(1.8)	8.0	(3.5)	9.0
Gain (loss) reclassified from AOCI and noncontrolling interest into income	$ (4.0)	$ (3.5)	$ (8.1)	$ (7.0)