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		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivatives Not Designated as Hedging Instruments
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	$ 44.9	$ (23.1)	$ (5.6)	$ (329.2)
Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in AOCI	11.2	(7.3)	(26.0)	35.0
Gain (Loss) Reclassified from AOCI and Noncontrolling Interests into Income	(1.0)	(2.4)	14.5	(3.0)
Commodity contracts | Derivatives Not Designated as Hedging Instruments | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	44.8	(23.5)	(7.4)	(328.3)
Commodity contracts | Derivatives Not Designated as Hedging Instruments | Revenues
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	0.1	0.3	1.9	(0.5)
Commodity contracts | Derivatives Not Designated as Hedging Instruments | Operating Expenses / Other Operating Income, Net
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in Income	0.0	0.1	(0.1)	(0.4)
Commodity contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in AOCI	0.0	0.0	0.0	0.0
Commodity contracts | Cash Flow Hedges | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (Loss) Reclassified from AOCI and Noncontrolling Interests into Income	0.0	0.1	0.0	(2.2)
Foreign currency contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in AOCI	11.5	(6.4)	6.2	26.0
Foreign currency contracts | Cash Flow Hedges | Cost of Sales
Derivative Instruments, Gain (Loss)
Gain (Loss) Reclassified from AOCI and Noncontrolling Interests into Income	0.2	0.4	17.4	9.6
Cross-currency contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in AOCI	0.3	(1.5)	0.0	6.0
Cross-currency contracts | Cash Flow Hedges | Interest Expense / Other Operating Income, Net
Derivative Instruments, Gain (Loss)
Gain (Loss) Reclassified from AOCI and Noncontrolling Interests into Income	0.1	8.6	0.3	8.5
Interest rate contracts | Cash Flow Hedges
Derivative Instruments, Gain (Loss)
Gain (Loss) Recognized in AOCI	(0.6)	0.6	(32.2)	3.0
Interest rate contracts | Cash Flow Hedges | Interest Expense
Derivative Instruments, Gain (Loss)
Gain (Loss) Reclassified from AOCI and Noncontrolling Interests into Income	$ (1.3)	$ (11.5)	$ (3.2)	$ (18.9)