Restructuring and Impairment Costs - Schedule of Restructuring Reserve (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Restructuring Reserve [Roll Forward]
Current restructuring reserve - other current liabilities	$ 85	$ 50	$ 85	$ 50
Noncurrent restructuring reserve - other noncurrent liabilities	90	0	90	0
2024 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	169		51
Plan charges	14		152
Utilized - cash	(10)		(27)
Noncash and other adjustments	2		(1)
Restructuring reserve ending balance	175		175
2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance		53		60
Plan charges		2		26
Utilized - cash		(8)		(45)
Noncash and other adjustments		3		9
Restructuring reserve ending balance		50		50
Employee Severance and Termination Benefits | 2024 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	175		56
Plan charges	14		152
Utilized - cash	(10)		(27)
Noncash and other adjustments	2		0
Restructuring reserve ending balance	181		181
Employee Severance and Termination Benefits | 2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance		57		69
Plan charges		2		26
Utilized - cash		(8)		(45)
Noncash and other adjustments		3		4
Restructuring reserve ending balance		54		54
Currency Translation | 2024 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance	(6)		(5)
Plan charges	0		0
Utilized - cash	0		0
Noncash and other adjustments	0		(1)
Restructuring reserve ending balance	$ (6)		$ (6)
Currency Translation | 2023 Restructuring Plan
Restructuring Reserve [Roll Forward]
Restructuring reserve beginning balance		(4)		(9)
Plan charges		0		0
Utilized - cash		0		0
Noncash and other adjustments		0		5
Restructuring reserve ending balance		$ (4)		$ (4)