Derivative Instruments and Hedging Activities - Location and Fair Values of Derivative Instruments and Hedging Activities (Detail) $ in Millions	Jun. 30, 2016 USD ($) T lb	Sep. 30, 2015 USD ($) T lb	Jun. 30, 2015 USD ($) T lb
Derivative Instruments [Line Items]
Derivative assets	$ 193	$ 233	$ 258
Derivative liabilities	$ 1,260	$ 1,727	$ 1,708
Copper [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | lb	5,436,000	14,648,000	8,479,000
Lead [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	8,475	6,785	10,892
Aluminum [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	1,240	5,700	4,365
Tin [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	423	2,080	2,836
Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivative assets	$ 22	$ 42	$ 46
Derivative liabilities	1,251	1,701	1,691
Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative assets	17	31	26
Designated as Hedging Instrument | Other Current Assets | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative assets	2	0	0
Designated as Hedging Instrument | Other Current Assets | Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative assets	0	1	1
Designated as Hedging Instrument | Other Current Assets | Cross-Currency Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative assets	0	5	16
Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative assets	3	5	3
Designated as Hedging Instrument | Other Noncurrent Assets | Equity swap
Derivative Instruments [Line Items]
Derivative assets	0	0	0
Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	28	37	26
Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	1	7	11
Designated as Hedging Instrument | Other Current Liabilities | Cross-Currency Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative liabilities	8	1	0
Designated as Hedging Instrument | Current Portion of Long-Term Debt | Fixed Rate Debt Swapped to Floating
Derivative Instruments [Line Items]
Derivative liabilities	404	801	801
Designated as Hedging Instrument | Long-Term Debt | Fixed Rate Debt Swapped to Floating
Derivative Instruments [Line Items]
Derivative liabilities	450	855	853
Designated as Hedging Instrument | Long-Term Debt | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Derivative liabilities	360	0	0
Not Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivative assets	171	191	212
Derivative liabilities	9	26	17
Not Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative assets	4	27	16
Not Designated as Hedging Instrument | Other Current Assets | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative assets	0	0	0
Not Designated as Hedging Instrument | Other Current Assets | Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative assets	0	0	0
Not Designated as Hedging Instrument | Other Current Assets | Cross-Currency Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative assets	0	0	0
Not Designated as Hedging Instrument | Other Noncurrent Assets | Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative assets	0	0	0
Not Designated as Hedging Instrument | Other Noncurrent Assets | Equity swap
Derivative Instruments [Line Items]
Derivative assets	167	164	196
Not Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	9	26	17
Not Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	0	0	0
Not Designated as Hedging Instrument | Other Current Liabilities | Cross-Currency Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative liabilities	0	0	0
Not Designated as Hedging Instrument | Current Portion of Long-Term Debt | Fixed Rate Debt Swapped to Floating
Derivative Instruments [Line Items]
Derivative liabilities	0	0	0
Not Designated as Hedging Instrument | Long-Term Debt | Fixed Rate Debt Swapped to Floating
Derivative Instruments [Line Items]
Derivative liabilities	0	0	0
Not Designated as Hedging Instrument | Long-Term Debt | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Derivative liabilities	$ 0	$ 0	$ 0