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	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss)
Gain (Loss) recognized in income	$ (44.7)	$ (289.2)
Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI	11.0	11.6
Gain (loss) reclassified from AOCI and Noncontrolling Interest into income	8.5	(3.6)
Commodity Contracts | Derivatives Not Designated as Hedging Instruments | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (Loss) recognized in income	(46.2)	(292.5)
Commodity Contracts | Derivatives Not Designated as Hedging Instruments | Revenues
Derivative Instruments, Gain (Loss)
Gain (Loss) recognized in income	1.6	3.8
Commodity Contracts | Derivatives Not Designated as Hedging Instruments | Operating Expenses / Other Operating Income, Net
Derivative Instruments, Gain (Loss)
Gain (Loss) recognized in income	(0.1)	(0.5)
Commodity Contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI	0.0	0.0
Commodity Contracts | Cash Flow Hedges | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (loss) reclassified from AOCI and Noncontrolling Interest into income	0.0	(2.4)
Foreign Currency Contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI	5.4	8.7
Foreign Currency Contracts | Cash Flow Hedges | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (loss) reclassified from AOCI and Noncontrolling Interest into income	9.1	2.7
Cross Currency Contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI	0.0	2.1
Cross Currency Contracts | Cash Flow Hedges | Interest Expense / Other Operating Income, Net
Derivative Instruments, Gain (Loss)
Gain (loss) reclassified from AOCI and Noncontrolling Interest into income	0.0	0.0
Interest Rate Contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in AOCI	5.6	0.8
Interest Rate Contracts | Cash Flow Hedges | Interest Expense
Derivative Instruments, Gain (Loss)
Gain (loss) reclassified from AOCI and Noncontrolling Interest into income	$ (0.6)	$ (3.9)