Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Percent of total assets domestic plans	69.00%
Cost of the savings incentive plan	$ 178	$ 153	$ 111
Fixed Income Funds
Defined Benefit Plan Disclosure [Line Items]
Company's Target allocation percentage for asset mix	45.00%
Diversified
Defined Benefit Plan Disclosure [Line Items]
Company's Target allocation percentage for asset mix	21.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Company's Target allocation percentage for asset mix	34.00%
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 2,242	3,222	3,045
Pension plan projected benefit obligations	2,634	3,889	$ 3,953
Employer contribution	198	66
Foreign Plans | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	705	1,033
Pension plan projected benefit obligations	$ 772	1,320
Percent of total plan assets foreign plans	31.00%
Foreign Plans | Pension Plans | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	$ 190	297
United States | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	1,537	2,189
Employer contribution	134
United States | Pension Plans | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Pension plan assets at fair value	469	686
United States | Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension plan projected benefit obligations	$ 101	$ 138