Derivative Instruments and Hedging Activities - Location and Fair Values of Derivative Instruments and Hedging Activities (Detail) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2021 USD ($) T shares	Sep. 30, 2021 USD ($) T shares	Apr. 30, 2021 USD ($)
Derivative Instruments [Line Items]
Hedge Percentage For Foreign Exchange Transactional Exposures Minimum	70.00%
Hedge Percentage For Foreign Exchange Transactional Exposures Maximum	90.00%
Derivative assets	$ 75	$ 57
Derivative liabilities	$ 2,871	$ 2,936
Interest Rate Swaps
Derivative Instruments [Line Items]
Derivative, Notional Amount			$ 500
Copper [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	3,314	2,656
Aluminum [Member]
Derivative Instruments [Line Items]
Derivative, Nonmonetary Notional Amount | T	7,193	5,159
Equity swap
Derivative Instruments [Line Items]
Derivative, amount of hedged ordinary shares | shares	0.3	0.3
Derivative, Amount of Hedged Item	$ 23	$ 23
Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivative assets	30	17
Derivative liabilities	2,858	2,930
Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative assets	27	15
Designated as Hedging Instrument | Other Current Assets | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative assets	3	2
Designated as Hedging Instrument | Other Noncurrent Assets | Equity swap
Derivative Instruments [Line Items]
Derivative assets	0	0
Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	12	11
Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	1	1
Designated as Hedging Instrument | Long-term Debt | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Derivative liabilities	2,845	2,918
Not Designated as Hedging Instrument
Derivative Instruments [Line Items]
Derivative assets	45	40
Derivative liabilities	13	6
Not Designated as Hedging Instrument | Other Current Assets | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative assets	17	17
Not Designated as Hedging Instrument | Other Current Assets | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative assets	0	0
Not Designated as Hedging Instrument | Other Noncurrent Assets | Equity swap
Derivative Instruments [Line Items]
Derivative assets	28	23
Not Designated as Hedging Instrument | Other Current Liabilities | Foreign Currency Exchange Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	13	6
Not Designated as Hedging Instrument | Other Current Liabilities | Commodity Derivatives
Derivative Instruments [Line Items]
Derivative liabilities	0	0
Not Designated as Hedging Instrument | Long-term Debt | Foreign Currency Denominated Debt [Member]
Derivative Instruments [Line Items]
Derivative liabilities	$ 0	0
Two Point Zero Percent Due Two Thousand Thirty One | Johnson Controls International plc (JCI) and Tyco Fire & Security Finance S.C.A. (TFSCA)
Derivative Instruments [Line Items]
Debt Instrument, Face Amount		$ 500