Derivative Instruments and Hedging Activities - Location and Fair Values of Derivative Instruments and Hedging Activities (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012
Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	$ 20	$ 34	$ 28
Derivatives Liabilities under ASC 815	769	874	880
Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	8	14	12
Designated as Hedging Instrument | Other Current Assets | Commodity Derivatives
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815		11	1
Designated as Hedging Instrument | Other Current Assets | Interest Rate Swaps
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	3	2
Designated as Hedging Instrument | Other Current Assets | Cross-Currency Interest Rate Swaps
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	7	1	8
Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Swaps
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815		6	7
Designated as Hedging Instrument | Other Noncurrent Assets | Cross-Currency Interest Rate Swaps
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	2
Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivatives Liabilities under ASC 815	8	17	18
Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivatives Liabilities under ASC 815	7		5
Designated as Hedging Instrument | Current Portion of Long-Term Debt | Fixed Rate Debt Swapped to Floating
Derivative Instruments [Line Items]
Derivatives Liabilities under ASC 815	753	401	100
Designated as Hedging Instrument | Long-Term Debt | Fixed Rate Debt Swapped to Floating
Derivative Instruments [Line Items]
Derivatives Liabilities under ASC 815		456	757
Designated as Hedging Instrument | Other Noncurrent Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivatives Liabilities under ASC 815	1
Not Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	161	131	126
Derivatives Liabilities under ASC 815	0	9	8
Not Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	3	8	8
Not Designated as Hedging Instrument | Other Noncurrent Assets | Equity swap
Derivative Instruments [Line Items]
Derivatives Assets under ASC 815	158	123	118
Not Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivatives Liabilities under ASC 815		$ 9	$ 8