Employee Benefit Plans - Additional Information (Details) $ in Millions		12 Months Ended
		Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2022 USD ($) Employee
Defined Benefit Plan Disclosure [Line Items]
Pre-65 health care cost increase trend rate		7.20%
Future Pre-65 health care cost trend rate		4.00%
Number of employees transferred upon divestiture | Employee				40
Actuarial gain				$ 1
Defined benefits plan overfunded		$ 18
Defined Benefit Plan, Plan Assets Allocation [Abstract]
Historical investment strategy asset mix, fixed income (in hundredths)		47.60%
Historical investment strategy asset mix, risk assets (in hundredths)		38.80%
Historical investment strategy asset mix, other securities assets (in hundredths)		13.60%
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan, Plan Assets Allocation [Abstract]
Actual contributions to benefit plans in period		$ 7	$ 3
Estimated future contributions in current next fiscal year		6
Foreign Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Plan Assets Allocation [Abstract]
Actual contributions to benefit plans in period		8	5
Estimated future contributions in current next fiscal year		5
Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expects to recognize of prior service credit in accumulated other comprehensive income as next fiscal year		1
Prior service credit recognized in accumulated other comprehensive income		1	1
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Actuarial gain	[1]	(11)	0	$ 16
Prior service credit recognized in accumulated other comprehensive income		2	2
Weighted-Average Plan Assumptions [Abstract]
Defined benefit plan, accumulated benefit obligation		$ 284	$ 250
Expected long-term rate of return on plan assets		4.99%	4.25%	2.89%
Other Pension Plan, Postretirement or Supplemental Plans [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Company contributions to other employee benefit savings plans		$ 21	$ 23	$ 23
Postemployment benefits liability, noncurrent		$ 4	$ 4

[1] These components are classified within the other net periodic benefit loss (income) caption on the Statements of Consolidated Comprehensive Income (Loss).