Restructuring and Impairment Costs - Changes in Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	$ 182	$ 51	$ 60
Plan charges	58	169	39
Utilized - cash	(104)	(43)	(53)
Noncash adjustment - (under) overspend and other	(2)	5	5
Restructuring reserve ending balance	134	182	51
Current restructuring reserve - other current liabilities	69
Noncurrent restructuring reserve - other noncurrent liabilities	65
Restructuring Reserve, Net	$ 134	$ 182	$ 51
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring and impairment costs	Restructuring and impairment costs	Restructuring and impairment costs
Employee Severance and Termination Benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	$ 181	$ 56	$ 69
Plan charges	58	169	39
Utilized - cash	(104)	(43)	(53)
Noncash adjustment - (under) overspend and other	(7)	(1)	1
Restructuring reserve ending balance	128	181	56
Restructuring Reserve, Net	128	181	56
Currency Translation and Other
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	1	(5)	(9)
Plan charges	0	0	0
Utilized - cash	0	0	0
Noncash adjustment - (under) overspend and other	5	6	4
Restructuring reserve ending balance	6	1	(5)
Restructuring Reserve, Net	$ 6	$ 1	$ (5)