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Restructuring and Impairment Costs - Changes in Reserve (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	$ 51	$ 60	$ 115
Restructuring reserve ending balance	182	51	60
Current restructuring reserve - other current liabilities	87
Noncurrent restructuring reserve - other noncurrent liabilities	95
Restructuring Reserve, Total	$ 182	51	60
Restructuring Charges, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring and impairment costs
2022 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges			25
Utilized - cash			(57)
Noncash adjustment - (under) overspend and other			(23)
2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges		39
Utilized - cash		(53)
Noncash adjustment - (under) overspend and other		5
2024 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges	$ 169
Utilized - cash	(43)
Noncash adjustment - (under) overspend and other	5
Employee Severance and Termination Benefits
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	56	69	112
Restructuring reserve ending balance	181	56	69
Restructuring Reserve, Total	181	56	69
Employee Severance and Termination Benefits \| 2022 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges			25
Utilized - cash			(57)
Noncash adjustment - (under) overspend and other			(11)
Employee Severance and Termination Benefits \| 2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges		39
Utilized - cash		(53)
Noncash adjustment - (under) overspend and other		1
Employee Severance and Termination Benefits \| 2024 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges	169
Utilized - cash	(43)
Noncash adjustment - (under) overspend and other	(1)
Currency Translation and Other
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	(5)	(9)	3
Restructuring reserve ending balance	1	(5)	(9)
Restructuring Reserve, Total	1	(5)	(9)
Currency Translation and Other \| 2022 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges			0
Utilized - cash			0
Noncash adjustment - (under) overspend and other			$ (12)
Currency Translation and Other \| 2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges		0
Utilized - cash		0
Noncash adjustment - (under) overspend and other		$ 4
Currency Translation and Other \| 2024 Restructuring Plan
Restructuring Reserve [Roll Forward]
Plan charges	0
Utilized - cash	0
Noncash adjustment - (under) overspend and other	$ 6