Derivative Instruments and Hedging Activities - Location and Fair Values of Derivative Instruments and Hedging Activities (Detail) € in Millions, shares in Millions, $ in Millions, ¥ in Billions	3 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2018 USD ($) T Swap shares	Dec. 31, 2016	Jun. 30, 2018 USD ($) T Swap	Sep. 30, 2017 USD ($) T Swap shares	Jun. 30, 2018 EUR (€) T Swap	Jun. 30, 2018 JPY (¥) T Swap	Sep. 30, 2017 EUR (€) T Swap	Sep. 30, 2017 JPY (¥) T Swap	Sep. 30, 2016 USD ($) Swap
Derivative Instruments [Line Items]
Hedge Percentage For Foreign Exchange Transactional Exposures Minimum			70.00%
Hedge Percentage For Foreign Exchange Transactional Exposures Maximum			90.00%
Number of Interest Rate Derivatives Held | Swap	0		0	0	0	0	0	0
Number of interest rate derivatives terminated		4
Derivative, amount of hedged ordinary shares | shares	1.8			1.4
Derivative assets	$ 81		$ 81	$ 91
Derivative liabilities	$ 2,948		$ 2,948	$ 2,105
Copper [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	2,948		2,948	1,962	2,948	2,948	1,962	1,962
Polypropylene [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	8,540		8,540	19,563	8,540	8,540	19,563	19,563
Lead [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	31,009		31,009	24,705	31,009	31,009	24,705	24,705
Aluminum [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	3,885		3,885	2,169	3,885	3,885	2,169	2,169
Tin [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	2,276		2,276	1,715	2,276	2,276	1,715	1,715
Equity swap
Derivative Instruments [Line Items]
Derivative, Amount of Hedged Item	$ 73		$ 73	$ 58
Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Notional amount | ¥						¥ 35		¥ 35
Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivative assets	10		10	36
Derivative liabilities	2,926		2,926	2,080
Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative assets	8		8	27
Designated as Hedging Instrument | Other Current Assets | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative assets	2		2	9
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	7		7	21
Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	3		3	1
Designated as Hedging Instrument | Long-term Debt | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Derivative liabilities	2,916		2,916	2,058
Not Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivative assets	71		71	55
Derivative liabilities	22		22	25
Not Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative assets	11		11	0
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 Noncurrent Assets | Equity swap
Derivative Instruments [Line Items]
Derivative assets	60		60	55
Not Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	22		22	25
Not Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
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
One Point Four Percent Due Two Thousand Eighteen | Interest Rate Swaps
Derivative Instruments [Line Items]
Number of Interest Rate Derivatives Held | Swap									3
Notional amount									$ 300
Debt Instrument, Interest Rate, Stated Percentage									1.40%
2.6% due 2017 | Interest Rate Swaps
Derivative Instruments [Line Items]
Number of Interest Rate Derivatives Held | Swap									4
Notional amount									$ 400
Debt Instrument, Interest Rate, Stated Percentage									2.60%
7.125% due 2017 | Interest Rate Swaps
Derivative Instruments [Line Items]
Number of Interest Rate Derivatives Held | Swap									1
Notional amount									$ 150
Debt Instrument, Interest Rate, Stated Percentage									7.125%
One billion euro net investment hedge [Member] | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Notional amount | €					€ 1,000		€ 1,000
423 million euro net investment hedge [Member] | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Notional amount | €					423		423
58 million euro net investment hedge [Member] | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Notional amount | €					€ 58		€ 58